A.C.E. 1/ACE CD 1.iso/files/docs/devpac2d.lha/DevpacV2Part1.doc

Text File | 1994-11-27 | 112.5 KB | 2,765 lines

                          DEVPAC 2 PART 1

Originaly typed in for DEVPAC ST by THE ANIMAL HOUSE. Converted to
DEVPAC AMIGA by PARASITE of LSD. Over 12 continueous hours of typing
to convert these so I hope you appreciate them!


CHAPTER 1: INTRODUCTION

ALWAYS MAKE A BACK-UP
        Before using Devpac AMIGA you should make a back-up copy of
the original disk and put the original away in a safe place. It is not
copy-protected to allow easy back-up and to avoid inconvenience. This
disk may be backed up using the Workbench or any back-up utility.

        NOTE: The original DEVPAC master disk had a technical support
serial registration number, but you wont get this!.

REGISTRATION CARD
        Enclosed with the manual is a registration card (but not for
you, and you also get a free 68000 Pocket Guide (£2.95 from any
good bookshop.)

THE README FILE
        As with all Hisoft products Devpac AMIGA is continually being
improved and the latest details cannot be included in this manual
may be found in the README.S file on the disk. If you are not already
in th CLI you should wait for any disk activity to stop. Press CTRL
and both AMIGA keys (A software reset), insert your DEVPAC disk. Once
in the CLI this file should be read by entering the command:

type readme (RETURN)

This display can be paused by holding down the menu button on the
mouse.

INTRODUCTION TO THE CLI
        Like most other programming developement tools, DeVPAC AMIGA
is designed to be run from the CLI (Command Line Interface). If you
examine the disk from the Workbench icon interface you won't see many
icons on the disk because of this.
        The CLI is deliberatly hidden from the average user, but as a
programmer you will need to use it, although most of your developement
time will be spent in th DEVPAC programs rather than the CLI.
        DEVPAC disk one is a modified Workbench disk and to start with
you should boot your machine as normal, with a kickstart disk if
required, but when asked for workbench, insert DEVPAC disk one. If you
have already booted from another disk, you should wait for all disk
activity to stop, insert DEVPAC and preform a software reset.
        The CLI is similar in concept to other non-iconic computers,
such as those running MS-DOS or CP/m. It works by you entering
commands such as:

dir (RETURN)

to get a directory of the disk. There is a full description on how to
use the CLI and tutorial in the AMIGA user manuel.

        NOTE: If you have a non-UK keyboard, you may need to modify
your s/startup-sequence file on your DEVPAC back-up disk, although
this may have been done for you! See the readme for more details.

BACKUP DETAILS
        Before making your security backups please ensure your master
disks are write protected. It is recommended the backups made are
regually virus checked with a reliable virus killer, or life could
become very nasty!.

ONE-DRIVE SYSTEMS
        Once you have booted the DEVPAC disk one enter the command

diskcopy df0: to df0: (RETURN)

Then follow the prompts given. The disk to copy from is our write-
protected master disk one the disk to copy to should be a write-
enabled blank disk. Then repeat the procedure with disk two.

TWO-DRIVE SYSTEMS
        Enter the command:

diskcopy df0: to df1: (RETURN)

inset a write-enabled blank disk in the internal drive, and the write-
protected DEVPAC disk one in the external drive and follow the prompts
given. Repeat the procedure with disk two.

MAKING A WORK DISK
        Although you now have a back-up, the disk as supplied dosen't
have room on it for large programs, and it is best to make one or more
work disks when you want to start serious programming. Exactly how you
do this depends on your hardware confuguration.

ONE-DRIVE SYSTEMS
        For single drive users it is best to get rid of as much as you
can fron the DEVPAC disk. Prime candidates are all .info files
together with the printer drivers and keymap files not required.
Deleting Preferances will save space, but this may be useful.
        If you follow these reccomendations the commands required (on
another backup) would be:

cd df0: (RETURN)
delete #?.info (RETURN)
cd devs/printers (RETURN)
dir (RETURN)

This will produce a list of printer drivers. Use the delete command to
erase those you do not need.

cd devs/keymaps (RETURN)
dir (RETURN)

This will produce a list of keymap files. Continue as above.

If space still bets tight you could start deleting the examples
directory, seldom used include files and some commands in the c
directory.

TWO-DRIVE SYSTEMS
        Two drive owners are reccomended to keep the workbench disk
free of all source code, and put such files together with the include
files on the disk in th external drive. The commands to do this (using
another back-up) would be:
        (NOTE: The first command formats a blank disk in the  external
drive losing all data. If you are using a pre-formatted disk you don't
need to do this)

format drive df1: name "source" (RETURN)

Insert a blank disk in the external drive, then press (RETURN) to
format it.

cd df0: (RETURN)
makedir df1:include (RETURN)
makedir df1:examples (RETURN)
copy include to df1:include all (RETURN)
copy examples to df1:examples all (RETURN)
delete include all (RETURN)
delete examples all (RETURN)

        The commands create directories on the external drive for the
example programs and the include files, then delete them from the disk
in the internal drive (which must, of course, be a back-up).

        You will now probably want to copy the program files from
DEVPAC disk two to your workbench disk. To do this insert your back-up
disk two of DEVPAC master disk in df1: and type:

copy df1:c to df0:c all (RETURN)
cd df1: (RETURN)

        This final command changes the default directory to the
external drive so you can edit source files there more easily. It is
often worthwile to build such a command into your startup-sequence.

HARD DISK USERS
        Hard disk users should firstly boot from the hard disk, and
not the DEVPAC workbench disk. Having done this, the DEVPAC disk one
should be placed in the internal drive and the following commands
executed, to copy the programs onto the hard disk:

copy df0:c/genam2 to c: (RETURN)
copy df0:c/monam2 to c: (RETURN)
copy df0:c/genim2 to c: (RETURN)

        Next the two subdirectories should be copied, and this depends
on your requiremants - for example, you may wish to make a seperate
DEVPAC directory on your herd disk. Whatever you choose you will need
to copy the whole of directories "include" and "examples". If you
choose to have a seperate DEVPAC sub-directory the commands would be
(assuming dh0: is the name of your hard disk):

makedir dh0:devpac (RETURN)
copy df0:include to dh0:devpac all (RETURN)
copy df0:examples to dh0:devpac all (RETURN)

        Note that if you put the example directory within another
directory you will have to change the INCDIR directives at the
beginning of them for correct assembly.

        You will also want to copy the following file from your DEVPAC
disk two backup.

copy df0:c/blink to dh0:c

        It probably isn't worth copying the other files until you need
them.

THE DEVELOPMENT CYCLE
        The purpose of DEVPAC is to allow you to enter assembly
language programs, assemble  them to machine-code and debug them if
(or should that be 'when') they don't work. Depending on your
application, you may also be using a linker to join together seperate
modules, possibly with the output from a high level language compiler.
Of course the faster the development cycle, the faster you can get
your programs up and running and DEVPAC was designed to be as fast and
powerful as possible. The link stage is optional, as is the Compile
stage.

DEVPAC DISK CONTENTS
        DEVPAC is supplied on two 3.5" disks, the first a standard
Workbench 1.2 disk, configured to enter the CLI on boot, and the other
contains additional files.

DISK 1
Programs in c directory:
GENAM2 - Screen editor and control program
GENIM2 - Assembler
MONAM2 - Debugger

Other files:
LIBS/LIBFILE.MONAM - Binary file used by debugger
LIBS/ARP.LIBRARY   - Additional library
README             - Latest details about DEVPAC

Additional subdirectories:
INCLUDE  - Contains files for accessing the operating system.
EXAMPLES - The source code to various example programs.

DISK 2
Programs in the c directory:
BLINK     - PD linker
CONVERTFD - FD file conversion utility
CONVERTI  - Include file conversion utility

+ some Workbench files for which there is insufficient room on disk
one.

Text files:
BLINK.DOC - Instructions for linker

Additional subdirectories:
INCLUDE.CBM   - The original Commodore include files with comments
INCLUDE.STRIP - The original Commodore include files without comments
FD.FILES      - The original Commodore fd files. Includes which
                registers are used when calling libraries.
LIBRARY       - Contains amiga.lib, debug.lib
ARP           - Contains parts of Charlie Heaths AmigaDOS replacement
                project (ARP)

HOW TO USE THE MANUAL
     This manual makes no attempt to teach 68000 assembly language
programming or to detail the instruction set.  For the former, the
bibliography  lists  suitable  books,  while for  the  latter  the
supplied  Pocket  Guide is very useful.  The  Appendices  give  an
overview of the technical aspects of the AMIGA but they are not
intended as a complete technical description of the machine.
     This manual is set out in five chapters, this introduction, a
chapter on the screen editor,  a chapter on the macro assembler, a
chapter on the debugger, then a chapter on the linker. In addition
there  are  eight  Appendices  which  detail  various   additional
information.  We suggest you use the manual in a way that  depends
on what type of user you are:

DEVPAC VERSION 1 USERS
Turn  to  Appendix  F and read the  section  describing  the  new
features,  then  read the Reference section of Chapter 4  if  you
intend  using MonAM, as it has changed considerably. You will then
probably want to dip into the manual to read about the new features
that interest you.

BEGINNERS
     If you are a newcomer to assembly language then we  recommend
that you read one of the books in the Bibliography alongside  this
manual.
     At  the end of this chapter there is a simple tutorial  which
you should follow to familiarise yourself with the use of the main
parts of the program suite.
     Chapter  2  details  the editor and is  well  worth  reading,
though much of Chapter 3,  detailing the assembler,  is liable  to
mean  nothing  until you become  more  experienced.  The  Overview
section  of  Chapter 4,  the debugger,  is  strongly  recommended,
though Appendices can be left  for  a  while.
Looking  at the supplied source code may be helpful.

EXPERIENCED USER
     If you are experienced in the use of 68000 assembly  language
but have not used DEVPAC before then here is a very quick way of
assembling a source file:
     Load GENAM2, Press Amiga-L and select your file which will
load into the editor. Press Amiga-A and select the options which you
require  - if generating executable code then click on the  Memory
button  for  additional  speed.  Pressing RETURN  will  start  the
assembler, which may be paused by pressing any key, RETURN resumes.
Any assembly errors will be remembered and on return to the editor
you  will  be placed on the first one.  Subsequent errors  may  be
found by pressing Amiga-J.
     To run your successfully-assembled program (if assembled  to
memory ) press Amiga-X. If assembled to disk, leave the editor and
run it from CLI.
     As  a  quick  introduction  to  the  debugger  the  following
tutorial is recommended.  If you have any problems please read the
relevant section of the manual before contacting us for  technical
support.

A VERY QUICK TUTORIAL
     This  is a quick tutorial intended to let you see  how  quick
and easy it is to edit, assemble and debug programs with DEVPAC.
     In  this tutorial we are going to assemble and run  a  simple
program,  which  contains two errors,  and debug it.  The  program
itself  is  intended to print a message.
     To  run this tutorial you must be in the CLI. If you are not you
should wait for any disk activity to stip, eject all disks, press
(CTRL) and both Amiga keys, and insert the backup of DEVPAC disk one.
It is convenient if we make the current directory the one where our
source program is, with the command:

cd examples (RETURN)

Next load the editor/assembler, by typing:

genam2 (RETURN)

        After a short delay the screen will show an empty window: to
load  the  file you should move the mouse over the PROJECT menu and
hold the right mouse button, and release it on LOAD. A file selector
will then appear and the file we want is called DEMO.S. You should
click on the name to load followed by OK.
     When  the file has loaded the window will show the top  lines
of the file.  If you want to have a quick look at the program  you
may press (SHIFT)-(DOWNCURSOR) or (CTRL)-C to move to the next page.
     With  most  shorter  programs  it is best  to  have  a  trial
assembly  that doesn't produce a listing or binary file  to  check
the syntax of the source and show up any typing errors and so  on.
Move the mouse to the  Program menu and click on Assemble.
     A dialogue box will appear, which should be left alone except
the button near the bottom,  labelled NONE,  should be clicked on.
Click on the Assemble button or press RETURN and the assembly will
begin.
     The   assembler  will  report  an  error,   instruction   not
recognised, and pressing any key will return you to the editor. The
cursor will be placed on the incorrect line and the error  message
displayed in the status line.
     The program line should be changed from MOV.L to MOVE.L so do
this,  then  click on Assemble form the Program menu  again.  This
time  click on the Memory button,  this means the program will  be
assembled  into memory,  instead of onto disk.  This is very  much
faster  and  allows you to try things out  immediately,  which  is
exactly what we want.  Clicking on the Assemble button will  again
assemble  it,  and after you press a key to return to  the  editor
it's ready to run.
     The  assembly  worked this time, but don't run it yet - you will
probably get a software error task held message from the system and
have to reboot the machine.
     The  tool for finding bugs and checking programs is a debugger,
so click on  Debug from the Program menu.  The debugger is described
more fully later, but for now we just want to run the program from the
debugger to 'catch' any problems and find out what causes them, so
press (CTRL)-R.
     After a brief delay the message Address Error will appear at the
bottom  of the display, with the disassembly window showing the
current instruction:

start        MOVE.L    dosname,a1

     This will cause an address error because location dosname is at
an odd address which cannot be accessed with the MOVE.L instruction.
There should be a hash sign before the dosname to put the address of
dosname into the register a1. To return to the editor press (CTRL)-Q,
to ensure that the program will be killed and press Y to terminate the
program and the debugger. We can fix this bug in the source code.
     Press (AMIGA)-T, to go to the top of the file, then click on Find
from the Search menu.  We are going to find the errant instruction
so enter:

             MOVE.L

     Then press Return to start the search. The first occurrence is
the one we are looking for:

start        MOVE.L    dosname,a1

     Ahah! - this is the one, so add a hash to change it to

start        MOVE.L    #dosname,a1

     then assemble it again.  If you click on RUN from the Program
menu you should see the message,  and pressing any key will return
you to the editor.
     Although  the  program  now works we  shall  use  MONAM2,  the
debugger,  to trace through the program,  step by step. To do this
click on Debug from the Program menu, and the debugger will appear
with the message Breakpoint, showing your program.
     There are various windows, the top one displaying the machine
registers, the second a disassembly of the program, the third some
other memory.
     If you look at window 2, the disassembly window, you will see
the current instruction, which in our case is:

start        MOVE.L    #dosname,a1

     As  the  debug was specified in the source code  any  symbols
will appear in the debugger.
     Let's check the area around dosname. Press (AMIGA)-3 and you
should see the window 3's title inverted. Next press (AMIGA)-A and a
dialogue box will appear, asking WINDOW START ADDRESS? - to this
enter:

string

     (it  must  be  in lower-case) and  press  (RETURN).  This  will
re-display  window 3 at the address,  showing the message in  both
hex and ASCII.
     To  execute  this MOVE instruction press  Ctrl-Z.  This  will
execute the instruction then the screen will be updated to reflect
the  new  values of the program counter and register  A1.  If  you
press Ctrl-Z again the MOVEQ instruction will be executed and d0 will
be modified. The next two instructions are the expansion of the
CALLEXECOpenLibrary macro call. Use (CTRL)-z to single step the move
to a6 instruction.

        Next we have:

        jsr     _LVOOpenLiberary(a6)

        This is the call to the exec liberary. All calls to the AMIGAs
operating system have the same form. We don't want to single step this
- we know that amigaDOS works. To treat this system call as one
instruction use (CTRL)-T
        Now single step the next (TST.L d0). D0 should be non-zero; so
the Z flag won't be present in MONAM's register display area.
        Now you can continue to press (CTRL)-z until you get to:

        jsr _LVOOutput(a6)

        This is the call to the DOS.liberary to find our output
handle. Use (CTRL)-T to skip over this. Use (CTRL)-Z to continue
single stepping until we get to:

        jsr     _LVOWrite(a6)

        This is the call that will actually write our string on the
screen - lets make sure that the registers are set up correctly. d1
should have the output handle that came back from the output call in
d0. d2 should have the address of the message. If you look from d2 in
the register display you will see the ASCII bytes of the string. Now
use (CTRL)-T to skip over the Write call. To check that it worked
press the V key, then press any other key to return to monam (being
careful not ot activate any other windows meantime).
        Now all that is left is our de-initialisation. You can use the
(CTRL)-Z and (CTRL)-T commands to step through it as before.
        The last instruction in the program is an RTS. Single stepping
this will terminate Monam, for now, and return to the editor.

CHAPTER 2: SCREEN EDITOR

INTRODUCTION
     To  enter  and assemble your programs you need an  editor  of
some sort and an assembler. GenAM is our editor which loads and runs
the assembler. Genim as required giving the appearance of a full
screen editor and a fast, full specification assembler as one program.
It  also allows  you  to run your assembled programs directly  from
memory without  having  to quit the program or do a disk  access  and
to access a debugger at the press of a key.  The fact that all  these
features  are  combined in one program means that correcting
errors and making changes is as fast as possible without the  need
for slow disk accesses and other programs.
     This chapter details the use of the editor and how to
assemble program  - it does not detail the assembler or the
debugger themselves, they are covered in the following chapters.
     To  run GenAM, enter the command GENAM2 from the CLI. When it has
loaded it will open an empty window, ready for you to enter and
assemble your programs.

THE EDITOR
     A  text  editor is a program which allows you  to  enter  and
alter lines of text, store them on disk, and load them back again.
There  are two types of text editors:  line editors,  which  treat
each  line separately and can be very tricky to  use,  and  screen
editors,  which display your text a screen at a time.  The  latter
tend to be much easier to use.
     The GENAM is a screen editor which allows you to enter and edit
text and save and load from disk, as you would expect. It also lets
you print all or some of your text, search and replace text patterns.
It is intuition based, which means it uses all the user friendly
features of amiga programs that you have become familiar
with on your computer such as windows, menus and mice. However, if
you're a die-hard,  used to the hostile world of computers  before
the  advent of WIMP's,  you'll be pleased to know that you can  do
practically everything you'll want to do from the keyboard without
having to touch a mouse.
     The editor is 'RAM-based',  which means that the file you are
editing stays in memory for the whole time,  so you don't have  to
wait while your disk grinds away loading different sections of the
file  as you edit.  As the amiga can have so much memory, the  size
limitations often found in older computer editors don't exist with
GenAM;  if you have enough memory you can edit files of over  300k
(though make sure your disk is large enough to cope with saving it
if  you do !).
        As all editing operations, including things like searching,
are RAM based they act blindingly quickly. When you have typed in your
program it is not much use if you are unable to save it to disk,  so
the editor has a comprehensive range of save and load options,
allowing you to save all or part of the text and to load other files
into the middle of the current one, for example.
     To  get  things to happen in the editor,  there  are  various
methods available to you.  Features may be accessed in one or more
of the following ways;

     Using a single key, such as a Function or cursor key:

     Clicking on a menu item, such as SAVE:

     Using  a  menu  shortcut,   by  pressing  the right amiga key
     (subsequently  referred  to  as  (amiga))  in  conjunction   with
     another such as (AMIGA)-F for Find:

     Using  the control key (subsequently referred to as Ctrl)  in
     conjunction  with  another,  such as Ctrl-A for  cursor  word
     left:

     Clicking on the screen, such as in the window itself.

     The  menu short cuts have been chosen to be easy and  obvious
to  remember, the cursor key functions are based on those in the
amigaBASIC editor check, while the Ctrl commands are based on those
used  in Wordstar, and many other compatible editors since.
     If  at  any time you get stuck,  pressing the HELP  key  will
bring  up  a comprehensive display of the keys for  functions  not
visible in menus.

A FEW WORDS ABOUT REQUESTERS
        The editor makes extensive use of requesters,  so it  is
worth recapping how to use them,  particularly for entering  text.
The  editor's requesters contains string gadgets and buttons.
        String gadgets enables to enter and edit text, and are
depicted by a box containing the text, and with a block indicating the
cursor position. Characters may be typed in and corrected using the
(BACKSPACE), (DEL), and cursor keys. You can clear the whole edit
field by pressing (AMIGA)-X. Ypu can move the cursor to the beginning
by pressing (SHIFT) and left cursor key, or to the end by (SHIFT) and
right cursor key. If there is more than one editable text field in a
dialog box, you can move between them by clicking near them with the
mouse.
        Buttons  may  be  clicked on with the  mouse  and  cause  the
requester to go away.  Usually there is a default button, shown
by having a double border. Pressing (RETURN) on  the keyboard is
equivalent to clicking on the default button, so long as a string
gadget is active.
        Some requesters allow only a limited range of  characters
to  be  typed into them - for example the Goto Line requester.

THE FILE REQUESTER
        The file requester is used to select file names for the disk
input and output facilities of the editor. In it's simplest form all
you need is to click on the file on the cancel button. At the top of
Requester is the drawer specification, this determines which disk and
sub-directory is displayed and can include wildcards, for example the
specification:

df1:examples/#?.s

will display all files ending in .s. If you edit this specification,
pressing the (RETURN) key will cause the directory to be read and
displayed in the main part of the requester. Files may be selected by
clicking on them and pressing (RETURN) or clicking on OK. The file
list shows sub-directories with the (dir) prefix and the scroll bar
may be used to navigate the file list. Files mey be selected or the
requester cancelled while the directory is still being read! When
initially invoked, only the first fiew files will be displayed. To
update the file listm, click on the slider on the right of the
filename list.
        NOTE: Teh file requester uses the ARP libarary by Charlie
Heath. If this library is not found then a simple string gadget will
be used in it's place, in the same way as GenAm version 1. More
details of the ARP library can be found in the ARP sub-directory on
disk two.

ENTERING TEXT AND MOVING THE CURSOR
     Having loaded GenAM, you will be presented with an empty
window  with a status line at the top and an orange block, which is
the cursor, in the top left-hand corner.
     The  status  line  contains  information  about  the   cursor
position in the form of Line Column offsets as well as the  number
of  bytes of memory which are free to store your  text.  Initially
this  is  displayed as 59980,  as the default text size  is  60000
bytes.  You  may change this default if you  wish,  together  with
various other options,  by selecting Preferences, described later.
The  missing  20  bytes  are  used  by  the  editor  for  internal
information.  The  rest of the status line area is used for  error
messages, which will usually be accompanied with a 'display flash'
to alert you. Any message that get  printed wil  be removed
subsequently when you press a key.
     To enter text,  you type on the keyboard.  As you press a key
it  will  be shown on the screen and the cursor will  be  advanced
along the line.  If you are a good typist you may be able to  type
faster  than  the editor can re-display the  line;  if  so,  don't
worry,  as the program will not lose the keystrokes and will catch
up  when you pause.
        At the end of each line you press the (RETURN) key (or the
Enter key on the numeric pad) to start the next  line. You can correct
your mistakes by pressing the Backspace key, which deletes the
character to the left of the cursor, or the Delete key, which removes
the character the cursor is over.
     The  main  advantage  of a computer editor as  opposed  to  a
normal typewriter,  is its ability to edit things you typed a long
time  ago.  The  editor's large range of  options  allow  complete
freedom to move around your text at will.

CURSOR KEYS
     To move the cursor around the text to correct errors or enter
new characters, you use the cursor keys, (the arrows). If you move
the  cursor  past the right-hand end of the line  this  won't  add
anything to your text,  but it you type some text at the point the
editor  will  automatically add the text to the real  end  of  the
line.  If  you type in long lines the window display  will  scroll
sideways if necessary.
     If  you cursor up at the top of the window the  display  will
either  scroll  down if there is a previous  line,  or  print  the
message  Top of file in the status line.  Similarly if you  cursor
down  off the bottom of the window the display will either  scroll
up if there is a following line, or print the message End of file.
     For those of you used to Wordstar,  the keys Ctrl-S,  Ctrl-D,
Ctrl-E and Ctrl-X work in the same way as the cursor keys.
     To move immediately to the start of the current  line,  press
Ctrl  (left arrow),  to move to the end of the current line  press
Ctrl (right arrow).
     To  move  the cursor a word to the left,  press  Shift  (left
arrow) and to the right press Shift (right arrow). You cannot move
a  cursor past the end of a line with this.  A word is defined  as
anything surrounded by a space,  a tab or a start or end of  line.
The keys Ctrl-A and Ctrl-F also move the cursor left and sight  on
a word basis.
     To move the cursor a page up, you can click on the upper grey
part  of  the vertical scroll bar,  or press Ctrl-R or  Shift  (up
arrow). To move the cursor a page down, you can click on the lower
grey  part  of  the scroll bar,  or press Ctrl-C  or  Shift  (down
arrow).
     If you want to move the cursor to a specific position on  the
screen you move the mouse pointer to the required place and  click
(There is no Wordstar equivalent for this feature!)

TAB KEY
        The Tab key inserts a special character (ASCII code 9) into
your text, which on the screen looks like a number of spaces, but is
rather  different.  Pressing Tab aligns the cursor onto  the  next
'multiple of 8' column,  so if you press it at the start of a line
(column 1) the cursor moves to the next multiple of 8 +  1,  which
is column 9.  Tabs are very useful indeed for making items line up
vertically  and its main use in GenAM is for  making  instructions
line up.  When you delete a tab the line closes up as if a  number
of  spaces had been removed.  The advantage of tabs is  that  they
only  take  up 1 byte of memory,  bat can show on screen  as  many
more, allowing you to tabulate your program neatly. You can change
the  tab size before or after loading GenAM using the  Preferences
command described shortly.

BACKSPACE KEY
     The  Backspace key removes the character to the left  of  the
cursor.  If you backspace at the very beginning of a line it  will
remove  the 'invisible' carriage return and join the line  to  the
end of the previous line.  Backspacing when the cursor is past the
end of the line will delete the last character on the line, unless
the line is empty in which case it will re-position the cursor  on
the left of the screen.

DEL KEY
     The Delete key removes the character under the cursor and has
no effect if the cursor is past the end of the current line.

GOTO A PARTICULAR LINE
     To move the cursor to a particular line in the text, click on
Goto line..  from the Options menu, or press (AMIGA)-G. A requester
will appear allowing you to enter the required line number.  Press
(RETURN) or click on OK button to go to the line or click on  Cancel
to abort the operation.  After clicking on OK the cursor will move
to the specific line,  re-displaying if necessary,  or give  error
End of file if the line does't' exist.

GOTO TO TOP OF FILE
        To  move to the top of the text, click on Goto Top from the
Options  menu,  or  press (AMIGA)-T. The screen will be  re-drawn if
requested.
        NOTE: (AMIGA)-upcurser goes to the previous page not to the
top of file - this has been changed from DEVPAC 1 because some users
found this sequence too easy to hit by mistake.

GOTO END OF FILE
     To  move  the cursor to the start of the very  last  line  of
text, click on Goto Bottom, or press (AMIGA)-B
        NOTE: (AMIGA)-downcursor goes to the next page not to the
bottom of file - this has been changed from DEVPAC 1 because some
users found this sequence too easy to hit by mistake.

QUITTING GENAM
          To leave GenAM, and remove it from memory, click on Quit
from the Project menu, or press (AMIGA)-Q. If changes have been made
to the text which have not  been saved to disk,  an alert box will
appear asking for confirmation. Clicking on Cancel will return you to
the editor, while clicking on OK will discard the changes and return
you to the CLI.

DELETING TEXT

DELETE LINE.
     The  current  line can be deleted from the text  by  pressing
Ctrl-Y.

DELETE TO END OF LINE.
        The text from the cursor position to the end of the current
line can be deleted by pressing Ctrl-Q. (This is equivalent to the
Wordstar sequence Ctrl-Q Y).

UNDELETE LINE
     When a line is deleted using either of the above commands  it
is  preserved in an internal buffer,  and can be re-inserted  into
the text by pressing Ctrl-U,  or the Undo key. This can be done as
many times as required,  particularly useful for repeating similar
lines or swapping over individual lines.

DELETE ALL TEXT
     To clear out the current text, click on Clear from the Project
menu, or press (AMIGA)-C. If you have made any changes to the text
that have not been saved onto the disk, a confirmation is required
and  the  requisite alert box will appear.  Clicking  on  OK  will
delete the text, or Cancel will abort the operation.

DISK OPERATIONS
        It is no use being able to type in text if you are unable to
save it anywhere perminently, or load it back subsequently, so the
editor has a comprehensive set of features to read from and write to
disk.

SAVING TEXT
     To save the text you are currently editing,  click on Save As
from the Project Menu, or press (AMIGA)-S. The File requester
will appear,  allowing you to select a suitable disk and filename.
Clicking  OK or pressing Return will then save the file  onto  the
disk.  If an error occurs a requester will appear showing a sutable
error message, or an AmigaDOS error number, the exact meaning of which
can be found in Appendix A.
     If you click on Cancel the text will not be  saved.  Normally
if  a  file  exists  with the same name it  will  be  deleted  and
replaced  with the new version,  but if Backups are selected  from
the  Preferences  options then any existing file will  be  renamed
with  extension .BAK (deleting any existing .BAK file) before  the
new version is saved.

SAVE
        If you have already done a save as (or a load), GenAm will
remember the name of the file and display it in the title bar of the
window. If you want to save it without having to bother with the file
requester. You can click on save on the Project menu, or press Shift-
(AMIGA)-S, and it will use the old name and save it as above. If you
try to sve without having previously specified a filename you will be
presented with a file requester, as in save as.

LOADING TEXT
     To  load a new file, click on Load from the Project menu, or
press (AMIGA)-L. If you have made any changes that have not been
saved, a confirmation will be required. The file requester will
appear, allowing you to specify the disk and filename. Assuming you do
not cancel, the editor will attempt to load the file. If  it will fit,
the file is loaded into memory and the window is re-drawn. If it will
not fit an alert box will appear warning you, and you should use
preferances to make the edit buffer size larger, then try to load it
again.

INSERTING TEXT
     If  you  want to read a file from disk and insert it  at  the
current  position in your text click on Insert File from the  File
menu or press (AMIGA)-I. The file requester will appear and assuming
that you do not cancel, the file will be read from the disk and
inserted, memory permitting.

CHANGE DIRECTORY
      This command lets you change the current directory that you are
using. Simply uses the file requester to change the directory you
wish.

SEARCHING AND REPLACING TEXT
     To  find a particular section of text click on Find from  the
Search menu,  or press (AMIGA)-F. A dialogue box will appear, allowing
you to enter the Find and Replace strings. If you click on Cancel,
no action will be taken;  if you click Next (or press Return)  the
search will start forwards,  while clicking on Previous will start
the  search backwards.
        If you do not wish to replace, leave the Replace string empty.
If the search was successful, the screen will be re-drawn at that
point with the cursor positioned at the start of the string. If the
search string could not be found, the message Not Found will appear in
the status area and the cursor will remain unmoved. By default the
search is always case-independant, so for example if you enter the
search string as test you could find the words TEST,  Test or test.
If you click on the Upper & Lower case Different button the search
will be case dependant.
     To find the next occurrence of the string click on Find  Next
from  the Search menu,  or press (AMIGA)-N.  The search starts at the
position just before the cursor.
     To search for the previous occurrence of the string click  on
Find Previous from the Search menu, or press (AMIGA)-P.
     Having  found an occurrence of the required text,  it can  be
replaced  with the Replace string by clicking on Replace from  the
Search menu,  or pressing (AMIGA)-R.  Having replaced it,  the  editor
will then search for the next occurrence.
     If  you wish to replace every occurrence of the  find  string
with the replace string from the cursor position onwards, click on
Replace  All from the Search menu.  During the global replace  the
ESC  key  can be used to abort and the status area will  show  how
many  replacements were made.  There is deliberately  no  keyboard
equivalent for this to prevent it being chosen accidentally.
        To search and replace tab characters just press (TAB) when
typing in the dialog box. Other control characters may be searched for
by typing them in directly ((CTRL)-G for example). However do not use
this for CR((CTRL)-M) and LF((CTRL)-J) characters.

BLOCK COMMANDS
     A  Block is a marked section of text which may be  copied  to
another section, deleted, printed or saved onto disk. The function
keys are used to control blocks.
     Block markers remain during all editing commands, moving where
necessary. and are only reset by the commands New, Delete Block, and
Load.

MARKING A BLOCK
     The  start of a block is marked by moving the cursor  to  the
required place and pressing key F1.  The end of a block is  marked
by moving the cursor and pressing key F2. The start and end of the
block do not have to be marked in a specific order - if it is more
convenient you may mark the end of the block first.
     A marked block is highlighted by showing the text in reverse.
While  you  are  editing  a  line that  is  within  a  block  this
highlighting  will not be shown but will be re-displayed when  you
leave that line or choose a command.

SAVING A BLOCK
     Once a block has been marked, it can be saved by pressing key
F3.  If no block is marked,  the message What blocks! will appear.
If  the start of the block is textually after its end the  message
Invalid  block!  will  appear.  Both  errors  abort  the  command.
Assuming  a  valid block has been marked,  the file requester
will appear,  allowing you to select a suitable disk  and
filename.  If  you save the block with a name that already  exists
the  old  version will be overwritten - no backups are  made  with
this command.

COPYING A BLOCK
     A marked block may be copied,  memory permitting,  to another
part of the text by moving the cursor to where you want the  block
copied and pressing key F4. If you try to copy a block into a part
of itself, the message Invalid block will appear and the copy will
be aborted.

DELETING A BLOCK
     A  marked  block  may be deleted from the  text  by  pressing
Shift-F5.  The  shift key is deliberately required to  prevent  it
being  used accidentally.  A deleted block is  remembered,  memory
permitting, in the block buffer, for later use.
        There are two key sequences with this command for
compatibility with both DEVPAC version 2 and DEVPAC version 1.

COPY BLOCK TO BLOCK BUFFER
     The  current marked block may be copied to the block  buffer,
memory permitting,  by pressing Shift-F4.  This can be very useful
for  moving blocks of text between different files by loading  the
first,  marking  the block,  copying it to the block  buffer  then
loading the other file and pasting the block buffer into it.

PASTING A BLOCK
     A  block  in the block buffer may be pasted  at  the  current
cursor position by pressing F5.
    The  block  buffer will be lost if the edit  buffer  size  is
changed or an assembly occurs.

PRINTING A BLOCK
     A  marked  block may be sent to the printer  by  printing  on
Print Block from the File menu, or by pressing (AMIGA)-W. A requester
will appear asking for the name of the printer, which defaults to
PRT:, and clickingon ok will print the block. Of course the name can
be any valid AmigaDOS device, so you could "print" the block to disk
if required. It is differant to Save Block in that tabs are expanded
to spaces.
     If you try to print when there is no block marked,  the whole
file will be printed.

MISCELLANEOUS COMMANDS

HELP SCREEN
        The key equivalents for the commands not found in menus can
be seen by pressing the HELP key, or (AMIGA)-H. A dialogue box will
appear showing the function key uses, the version of GenAm that is
running and the total free memory in the system.

PREFERENCES
     Selecting Preferences..  from the Options menu will produce a
dialogue box allowing you to change several editor settings.

TABS
     By default,  the tab setting is 8, but this may be changed to
any value from 2 to 16.

TEXT BUFFER SIZE
     By default the text buffer size is 60000 bytes,  but this can
be changed from 4000 to 999000 bytes.  This determines the largest
file size that can be loaded and edited,  Care should be taken  to
leave  sufficient room in memory for assembly or running  MonAm.
Changing  the editor work-space size will cause any text  you  are
currently editing to be lost,  so a confirmation is required if it
has not been saved.

BACKUPS
     By  default the editor doesn't make backups of programs  when
you  save them,  but this can be turned on by clicking on the  Yes
radio button.

AUTO INDENTING
     It can be particularly useful when editing programs to indent
subsequent  lines from the left,  so the editor supports an  auto-
indent mode.  When active, an indent is added to the start of each
new line created when you press RETURN. The contents of the indent
of  the new line is taken from the white space (i.e.  tabs  and/or
spaces) at the start of the previous line.

END OF LINE
     By default (i.e. when Stop is selected) when you press cursor
left at the beginning of a line or cursor right at the end of line the
cursor does not move. Changing this item to wrap causes the cursor to
move to the previous line if you press cursor left at the beginning
and to the next line if you press curser left at the beginning and the
next line if you presscursor right at the end. The best way to find
out which you prefer is to try using both settings.

LOAD MONAM
     By  default  a  copy of MonAM is  loaded  during  the  editor
initialisation,  allowing it to be accessed at the press of a key.
Should  this not be required it can be disabled with this  option.
This will save around 24k of memory.  The new value of this option
will  only  have  an effect if you save the  preferences  and  re-
execute the editor.

AUTOSIZE WINDOW
     By default, Genam will not use the entire screen display, but if
this is selected then it will make it's initial window as large as
possible.

SAVING PREFERENCES
     If  you click on the Cancel button any changes you make  will
be ignored.  If you click on the OK button the  changes  specific
will remain in force until you quit the editor.  If you would like
the  configuration made permanent then click on the  Save  button,
which will create the file GENST2.INF on your disk.  Next time you
run GenST the configuration will be read from that file in the current
directory. In  addition to saving the editor configuration  the
current setting from the Assembly Options dialogue box are also saved.
If the .INF file is not found in the current directory when the editor
is loaded, the c: directory is also searched. This allows a global
settings as well as specific local ones.

ASSEMBLING & RUNNING PROGRAMS
     All assembly and run options can be found on the Program menu

ASSEMBLY
     To  assemble the program you are currently editing  click  on
Assemble from the Program menu, or press (AMIGA)-A. The meaning of the
various  options,  together  with the assembly process  itself  is
detailed in the next chapter.  The only option covered here is the
Output option.
     GenAM  can  assemble  to  disk,   to  memory,  or  nowhere  -
assembling to nowhere is ideal for syntax checking while  assembly
to  memory is much faster than to disk and good for trying  things
out quickly.
     If you assemble to disk and you haven't saved your program source
code yet the file will be based on the name NONAME.
     After  you  click on Assembly or press  RETURN  the  assembly
process will start,  describe more fully in the next  chapter.  At
the  end  of the assembly the program will wait for a  key  press,
allowing you to read any messages produced,  before returning  you
to the editor.  If there were any errors the editor will go to the
first  erroneous line and display the error message in the  status
bar.  Subsequent  errors  (and warnings) may  be  investigated  by
pressing (AMIGA)-J.

RUNNING PROGRAMS
     If you click on Run or press (AMIGA)-X (eXecute) you can then run
a  program  previously assembled into memory.  When  your  program
finishes it will return you to the editor.  If the assembly didn't
complete  normally for any reason then it is not possible  to  run
the program.
     If  your  program crashes badly you may never return  to  the
editor, so if in doubt save your source code before using this, or
the following command.
     If  only non-fatal errors occurred  during  assembly  (e.g.
undefined  symbols)  you  will  still be  permitted  to  run  your
program, at your own risk.

DEBUG
     If you wish to debug a program previously assembled to memory
click  on Debug form the Program menu, or press (AMIGA)-D. This will
invoke  MonAM to  debug your  program,  including  any  debugging
information specified.  Pressing Ctrl-C from MonAM will  terminate
the debugger.
     If  the  Load  MonAM option is disabled this  option  is  not
available and the menu is disabled.

MONAM
     Clicking on MonAM from the Program menu, or pressing (AMIGA)-M,
will invoke MonAM in a similar way to if it was invoked by typing it's
name in CLI, but instantly, as it  is  already  in  memory.  You will
return  to  the  editor  on termination of the debugger.
     If  the  Load  MonAM option is disabled this  option  is  not
available and the menu is disabled.

JUMP TO ERROR
     During  an  assembly any warnings or errors  that  occur  are
remembered,  and can be recalled from the editor. Clicking on Jump
to  Error from the Program menu,  or pressing (AMIGA)-J will move  the
cursor  to the next line in your program which has an  error,  and
display  the  message in the status line of the  window.  You  can
step to the next one by pressing (AMIGA)-J again,  and so on,  letting
you  correct errors quickly and easily.  If there are  no  further
errors when you select this option the message No more errors will
appear,  or if there are no errors at all the message What errors!
will appear.

THE EDITOR WINDOW
        The window used by the editor works like the most other Amiga
windows, so you can move it around by using the drag gadget on the top
of it, you can change it's size by dragging on the size gadget and
control it's position relative to the other windows by using the front
and back gadgets. Clicking on the close gadget is equivelant to
choosing Quit fron the project menu. Like all intuition windows, it
has to be active for you to be able get at it's menu items. If you
have a larger than normal screen size (eg. a european PAL system which
has 256 vertical lines) you can re-size the window to be the full size
of your screen.
        When GenAm is busy doing a disk access or assembly the cursor
changes to an hourglass and all menu items are made grey.
        NOTE: When using GenAm (And MonAm) on PAL machines with
external RAM, you may sometimes get two mouse pointers; one will be
the normal intuition pointer, the other will be the custom pointer
allocated with the program you are using. Do not be alarmed - this
seems to be a harmless bug in intuition.

SYSTEM REQUESTERS
        When a system requester appears from the editor (eg. File not
found), pressing any key is equivelant to clicking on cancel.

CHAPTER 3: MACRO ASSEMBLER

INTRODUCTION
     GenAM is a powerful,  fast,  full  specification  assembler,
available  instantly  from within the editor or as a  stand  alone
program.  It  converts the text typed or loaded into  the  editor,
optionally  together  with the files read from the  disk,  into  a
binary file suitable for immediate execution or linking, or into a
memory image for immediate execution from the editor.

INVOKING THE ASSEMBLER

FROM THE EDITOR
     The  assembler  is  invoked from the editor  by  clicking  on
Assemble from the Program menu,  or by pressing (AMIGA)-A.  A dialogue
box will appear which looks like this (almost);

|------------------------------------------------|
| Program type   Executable    Linkable          |
| Symbols case   Dependant     Independant       |
| Debug info     None    Normal   Exports        |
| List           None  Screen  Printer  Disk     |
| Assembly       Fast          Slower            |
| Output to      None          Memory            |
|       ______________________________________   |
| Disk |______________________________________|  |
|                Assembly options                |
| Cancel                        Assemble         |
| _______________________________________________|

     PROGRAM  TYPE This lets you select between executable or
linkable format  output.  The differences between these  are  detailed
later.

     SYMBOLS  CASE  This lets you select whether labels  are  case
dependant or not. If case Dependant is selected then Test and test
would  be different labels,  if the case Independant  is  selected
then they would be the same.

     DEBUG  INFO  If  you wish to debug your  program  using  your
original  symbols you can select Normal or Extended  debug  modes.

     LIST  selecting Printer will divert the assembly listing to the
PRT: device, or selecting Disk will send the listing to a
file based on the source filename, but with the extension .LST.

     ASSEMBLER  Normally this option should be left as fast selected,
but if the assembler runs out of memory select slower. Selecting
Slower forces the assembler to use little memory as possible thus
slowing down things like reading include files.

     OUTPUT TO This lets you select where the output file is to be
created. None means it is 'thrown away', ideal for syntax checking
a program;  Memory means it is assemble into a buffer allowing  it
to be run or debugged instantly form the editor without having  to
create  a  disk  file:  Disk means a file  will  be  created.  The
selection  of the name of this file can be left to the  assembler,
using rules described shortly.
     The  first  two options may be specified in the  source  file
using the OPT directive.
     Having selected your required options you should click on the
Assemble  button (or press Return) to start the assembly.  At  the
end of assembly you should press any key to return to the  editor.
If any errors occurred the cursor will be positioned on the  first
offending line.

STAND ALONE ASSEMBLER

COMMAND LINE FORMAT
     The assembler, Genim2, may by invoked directly from the CLI.
The command line should be the form:

GenIm2   mainfile    <-options>  [-options]

     The  mainfile  should  be  the name  of  the  file  requiring
assembly and if no extension is specified defaults to ,S.  Options
should  follow  this  donated by a -  sign  then  an  alphabetical
character.   Allowed   options  are  shown  below  together   with
equivalent OPT directives :

     B    no binary file should be created

     C    case insensitive labels (OPT C-)

     D    debug (OPT D+)

     I    specify include directory (follow immediatly with path)

     L    linkable code (OPT L+)

     M    use slow(low memory) assembly mode. See above. Not the
          same as OPT m+

     O    specify output filename (follows immediately after O)

     P    specify  listing  filename  (should  follow  immediately
          after P) defaults to source filename with extension .LST

     Q    pause for key press after assembly

     T    specifies the tab setting for listing. For example -T10
          uses a tab setting of 10.

     X    used when generating linkable code to export only the
          exported (XDEFed) symbols (OPT X+)

     NOTE: The options used by GenIm2 are rather differant to those
used in DEVPAC version 1 but the same as DEVPAC version 2.

        The default is to create an executable binary file with  the
name based on the source file and output file type,  no  listing,
with no case sensitive labels. For example,

genim2    test  -b

assembles test.s with no binary output file

genim2    test  -oram:test -p -iminc/

assembles test.s into a binary file ram:test.prg and a listing  file
to test.lst, with an include directory of myinc.

genim2    test  -ldppprt:

assembles  test.s into linkable code with debug and a  listing
to  the printer as set using the Amiga Preferances tool.

OUTPUT FILENAME
     GenAM  has  certain rules regarding the  calculation  of  the
output filename, using a combination of that specified at assembly
time  (either in the Disk: string gadget in the requester) or
using the -O option on the command line) and the Output directive:
     If an output filename is explicitly given at assembly time then:
     name = explicit filename

else:
     if the Output directive has not been used then
          name = source filename without an extension or .O
     else if the Output directive specifies an extension then
          name = source filename + extension in Output
     else
          name = name in Output

ASSEMBLY PROCESS
     GenAM is a two-pass assembler; during the first pass it scans
all  the text in memory and from disk if required,  building up  a
symbol  table.  If  syntax  errors are found  on  the  first  pass
assembly these will be reported and assembly will stop at the  end
of  the  first  pass,   otherwise,  during  the  second  pass  the
instructions are converted into bytes,  a listing may be  produced
if required and a binary file can be created on the  disk.  During
the  second  pass any further errors and warnings will  be  shown,
together with a full listing and symbol table if required.
     During assembly, any screen output can be paused by holding down
the right mouse button or, when using the stand alone assembler, by
pressing  any key (pressing (RETURN) will  resume it).  Assembly  may
be  aborted  by pressing Ctrl-C, although doing so will make any
binary file being created  invalid  as  it  will be incomplete  and
should  not  be executed.

ASSEMBLY TO MEMORY
        To reduce development time GenAM can assemble  programs  to
memory, allowing immediate execution or debugging from the editor.
        A  program running from memory is just like any other  normal
AmigaDOS  program and should terminate using an RTS instruction with
the stack as the program was entered.
       Programs should be careful if they self-modify as a re-executed
program will be in its original state. The state is left as when the
program was previously executed.
       The current assembly options can be made the default on re-
loading the editor if Save Preferences is used.

BINARY FILE TYPES
     There are two types of binary files which may be produced  by
GenAM, for different types of applications. They are distinguished
by the extension on the filename:
     If there is no extension then this is a directly executable file,
or if the extension is .o or .obj then this is an AmigaDOS linkable
file.
     Actually there are two sorts of executable files; those that are
designed to be run from the CLI and those that are designed to be run
from workbench. The differance is in the code that is part of the
program; the assembler cannot tell the differance. This is described
later.
     .o files cannot be run immediatly, but have to be read into a
linker, usually with other sections, and are known as linkable object
modules.

TYPES OF CODE
    Unlike  most 8-bit operating systems,  but like  most  16-bit
systems,  an executable program under AmigaDOS will not be loaded at
a  particular  address  but,  instead,  be loaded  at  an  address
depending on the exact free memory configuration at that time.
     To get around the problem of absolute addressing the ST  file
format includes relocation information allowing GEMDOS to relocate
the  program  after it has loaded it but before  running  it.  For
example the following program segment:

               move.l #string, a0
               .
               .
               .
     string    dc.b   'Press any key',0

places the absolute address of string into a register, even though
at  assembly  time the real address of string cannot  possibly  be
known.  Generally  the programmer may treat addresses as  absolute
even though the real addresses will not be known to him, while the
assembler  (or  linker) will look after the  necessary  relocation
information.
    NOTE: For certain programs, normally games or cross machine
development an absolute address may be required,  for this  reason
the ORG directive is supported.

The syntax of the assembler will now be described.

ASSEMBLER STATEMENT FORMAT
     Each  line  that is to be processed by the  assembler  should
have the following format;

     Label     Mnemonic       Operand(s)          Comment
     Start     move.l         d0,(a0)+            store the result

     Exceptions  to  this  are  comment  lines,  which  are  lines
starting with an asterisk or semi-colon,  and blank  lines,  which
are  ignored.  Each field has to be separated from the  others  by
white space - any number or mixture of space and tab characters.

LABEL FIELD
     The label should normally start at line 1,  but if a label is
required  to start at another position then it should be  followed
immediately   by  a  colon  (:).   Labels  are  allowed   on   all
instructions, but are prohibited on some assembler directives, and
absolutely  required  on  others.  A  label  may  start  with  the
characters A-Z,  a-z,  or underline (_),  and may continue with  a
similar  set together with the addition of the digits 0-9 and  the
period (.).
     Labels  starting with a period are  local  labels,  described
later. Sequances of digits terminated by a $ are also labels. Macro
names and register equate symbols may not have periods in them,
though macro names may start with a period. By default the first 127
characters of labels are significant, though this can be reduced if
required.  Labels should not be the same as register names, or the
reserved words SR, CCR or USP.
     By default labels are case-sensitive though this may be changed.

     Some example legal labels are ;

test, Test, TEST, _test, _test.end, test5, _5test

     Some illegal labels are;

     5test, _&e, test>,

     There  are  certain reserved symbols  in  GenST,  denoted  by
starting with two underline characters.  These are __LK,  __RS and
__G2.

MNEMONIC FIELDS
     The  mnemonic  field  comes after the  label  field  and  can
consist  of 68000 assembler instructions,  assembly directives  or
macro  calls.  Some  instructions  and  directives  allow  a  size
specifier,  separated from the mnemonic by a period. Allowed sizes
are .B for byte,  .W for word, .L for long and .S for short. Which
size specifiers are allowed in each case depends on the particular
instruction or directive.  GenAM is case-sensitive to mnemonic and
directive names, so Move is the same as move and the same as mOvE,
for example.

OPERAND FIELD
     For those instructions or directives which require  operands,
this field contains one or more parameters,  separated by  commas.
GenST is case-sensitive regarding register names so they may be in
either or mixed case.

COMMENT FIELD
     Any  white space not within quotes found after  the  expected
operand(s)  is  treated  as a delimiter before the  start  of  the
comment, which will be ignored by the assembler.

EXAMPLES OF VALID LINES

               move.l  d0,(a0)+         comment is here

     loop      TST.W       d0

     lonely.label

        rts

* this is a complete line of comment

; and so is this

     indented: link A6,#-10 make room

a_string: dc.b 'spaces allowed in quotes' a string

EXPRESSIONS
     GenAm allows complex expressions and supports full  operator
precedence, parenthesis and logical operators.
     Expressions are in two types -absolute and relative - and the
distinction is important. Absolute expressions are constant values
which are known at assembly time. Relative expressions are program
addresses  which  are  not known at assembly-time  as the AmigaDOS
loader  can  put  the  program where  it  likes  in  memory.  Some
instructions and directives place restrictions on which types  are
allowed  and  some  operators cannot be used  with  certain  type-
combinations.

OPERATORS
     The operators available, in decreasing order of precedence, are:
     monadic minus (-) and plus (+)
     bitwise not (~)
     shift left (<<) and shift right (>>)
     bitwise And (&), Or (!), and Xor (^)
     multiply (*) and divide (/)
     addition (+) and subtraction (-)
     equality (=), less than (<), greater than (>)

     The comparison operators are signed and return 0 if false  or
-1  ($FFFFFFFF) if true.  The shift operators take the  left  hand
operand and shift it the number of bits in the right hand  operand
and vacated bits are filled with zeros.

     This precedence can be overridden by the parentheses ( and ).
With operators of equal precedence, expressions are evaluated from
left-to-right.  Spaces  in  expressions (other than  those  within
quotes  as ASCII constants) are not allowed as they are  taken  as
the separator to the comment.

     All expression evaluation is done using 32-bit signed-integer
arithmetic, with no checking of overflow.

NUMBERS
     Absolute numbers may be in various forms;

          decimal constants, e.g. 1029
          hexadecimal constants, e.g. $12f
          octal constants, e.g. @730
          binary constants, e.g. %1100010
          character constants, e.g. 'X'

     $ is used to denote hex numbers,  % for binary,  @ for  octal
and single ' or double quotes " for character constants.

CHARACTER CONSTANTS
     Whichever  quote is used to mark the start of a  string  must
also  be used to denote its end and quotes themselves may be  used
in  strings delimited with the same quote character by  having  it
occur  twice.  Character  constants can be upto  4  characters  in
length and evaluate to right-justified longs with null-padding  if
required.  For example, her are some character constants and their
ASCII and hex values:

     "Q"       Q              $00000051
     "hi"      hi             $00006869
     "Test"    test           $54657374
     "it's"    it's           $6974277C
     'it''s'   it's           $6974277C

     Strings  used  in DC.B statements follow  slightly  different
justification rules, detailed with the directive later.

     Symbols  used  in  expressions will  be  either  relative  or
absolute,  depending on how they were defined.  Labels within  the
source  will  be  relative,  while those  defined  using  the  EQU
directive  will be the same type as the expression to  which  they
are equated.
     The  use of an asterisk (*) denotes the value of the  program
counter at the start of the instruction or directive and is always
a relative quantity.

ALLOWED TYPE COMBINATIONS
     The  table below summarises for each operator the results  of
the various type combinations of parameter an d which combinations
are  not allowed.  An R denotes a Relative result,  an  A  denotes
absolute  and a * denotes that the combination is not allowed  and
will produce an error message if attempted.

                    A op A   A op R   R op A   R op R
Shift operators       A        *        *         *
Bitwise operators     A        *        *         *
Multiply              A        *        *         *
Divide                A        *        *         *
Add                   A        R        R         *
Subtract              A        *        R         A
Comparisons           A        *        *         A

ADDRESSING MODES
     The available addressing modes are shown in the table  below.
Please   note  that  GenST  is  case-insensitive   when   scanning
addressing modes, so D0 and a3 are both valid registers.

FORM      MEANING                                 EXAMPLE
Dn        data register direct                    D3
An        address register direct                 A5
(An)      address register indirect               (A1)
(An)+     address reg indirect + post-increment.  (A5)+
-(An)     address reg indirect + pre-increment.   -(A0)
d(An)     address reg indirect with displacement  20(A7)
d(An,Rn.s)address register indirect with index    4(A6,D4.L)
d.W       absolute short address                  $0410.W
d.L       absolute long address                   $12000.L
d(PC)     program counter relative with offset    NEXT(PC)
d(PC,Rn.s)program counter relative with index     NEXT(PC,A2.W)
#d        immediate data                          #26

n         denotes register number from 0 to 7
d         denotes a number
R         denotes index register, either A or D
s         denotes size, either W or L, when omitted defaults to W

When  using address register indirect with index the  displacement
may be omitted, for example

move.l    (a3,d2.l),d0

will assemble to the same as

move.l    0(a3,d2.l),d0

SPECIAL ADDRESSING MODES

CCR       condition code register
SR        status register
USP       user stack pointer

In  addition to the above,  SP can be used in place of A7  in  any
addressing mode, e.g. 4(SP,D3.W)
     The data and address registers can also be denoted by use  of
the reserved symbols R0 through R15. R0 to R7 are equivalent to D0
to D7,  R8 to R15 are equivalent to A0 to A7. This is included for
compatibility with other assemblers.

LOCAL LABELS
     GenAm supports local labels,  that is labels which are  local
to  a  particular area of the source code.  These are  denoted  by
starting  with  a period and are attached to  the  last  non-local
label, for example;

lenl      move.l    4(sp),a0
.loop     tst.b     (a0)+
          bne.s     .loop
          rts
len2      move.l    4(sp),a0
.loop     tst.b     -(a0)
          bne.s     .loop
          rts

    There  are  two labels called .loop in this code segment but the
first is attached to lenl, the second to len2.
    If you wish to use global labels starting with a dot you may use
OPT U+ to allow this and make the underline character introduce local
labels.
    The local labels .W and .L are not allowed to avoid confusion with
the absolute addressing syntax.

AMIGA MACRO ASSEMBLER LOCAL LABELS
    You may also use strings of decimal digits terminated by the $
sign as local labels. This facility has been provided for
compatability with other assemblers; we reccomend the use of form
shown above as this makes programs much more readable.

SYMBOLS AND PERIODS
     Symbols which include the period character can cause problems
with GenAm due to absolute short addressing.
     The Motorola standard way of denoting absolute short addresses
causes  problems as periods are considered to be part of a  label,
best illustrated by an example:

          move.l    vector.w,d0

where vector is an absolute value, such as a system variable. This
would  generate an undefined label error,  as the label  would  be
scanned as vector.w.  To get around this,  the expression, in this
case a symbol, may be enclosed in brackets, e.g.

          move.l    (vector).w,d0

though the period mat still be used after numeric expressions, e.g.

          move.l    $4.w,d0

    NOTE: GenAm version 1 also supported the use of \  instead  of  a
period to denote short word addressing and this is still supported
in this version,  but this is not recommended due to the potential
for \W and \L to be mistaken for macro parameters.

INSTRUCTION SET

WORD ALIGNMENT
     All  instructions  with the exception of DC.B  and  DS.B  are
always  assembled on a word boundary.  Should you require  a  DC.B
explicitly on a word boundary,  the EVEN directive should be  used
before  it.  Although all instructions that require it  are  word-
aligned,  labels with nothing following them are not word  aligned
and can have odd values. This is best illustrated by an example;

          nop                 this is always word aligned
          dc.b      'odd'
start
          tst.l     (a0)+
          bne.s     start

The  above  code would not produce the required  result  as  start
would have an odd value.  To help in finding such an  instructions
the assembler will produce an error if it finds an odd destination
in a BSR or BRA operand. Note that such checks are not made on any
other  instructions,  so it is recommended that you  precede  such
labels  with  EVEN  directives if you require  them  to  be  word-
aligned.  A  common error is deliberately not to do this,  as  you
know  the preceding string is an even number of  bytes  long.  All
will be well until the day you change the string...

INSTRUCTION SET EXTENSIONS
     The  complete 68000 instruction set is supported and  certain
shorthands are automatically accepted,  detailed below. A complete
description of the instruction set including syntax and addressing
modes can be found in any 68000 reference guide or in the supplied
pocket guide.

CONDITION CODE
The altenate condition codes HS and LO are supported in Bcc, DBcc
and Scc instructions, equivalent to CC and CS, respectively.

BRANCH INSTRUCTIONS
     To force a short branch use Bcc.B or Bcc.S,  to force a  word
branch  use  Bcc.W or to leave the optimiser  use  Bcc.  Bcc.L  is
supported for compatibility with GenAm 1 with a warning as it  is,
strictly  speaking,   a  68020  instruction.   A  BRA.S  to   the
immediately following instruction is not allowed and is converted,
with  a warning,  to a NOP.  A BSR.S to the immediately  following
instruction is not allowed and will produce an error.

BTST INSTRUCTION
     BTST is unique among bit-test instructions in supporting  PC-
relative addressing modes.

CLR INSTRUCTION
     CLR An is not allowed,  use SUB.L An,An instead (though  note
that the flags are not affected).

CMP INSTRUCTION
     If  the source is immediate then CMPI is used,  else  if  the
destination is an address register then CMPA is used, else if both
addressing modes are post-incremented then CMPM is used.

DBcc INSTRUCTION
     DBRA is accepted as an equivalent to DBF.

ILLEGAL INSTRUCTION
     This generates the op-cope word $4AFC.

LINK INSTRUCTION
     If the displacement is positive or not even a warning is given.

MOVE FROM CCR INSTRUCTION
     This  is a 68010 and upwards instruction,  converted  with  a
warning to MOVE from SR.

MOVEQ INSTRUCTION
     If the data is in the range 128-255 inclusive a warning  will
be  given.  It  may be disabled by specifying a long size  on  the
instruction.

ASSEMBLER DIRECTIVES
     Certain  pseudo-mnemonics  are  recognised  by  GenIm.  These
assembler  directives,  as  they are called,  are  not  (normally)
decoded into opcodes, but instead direct the assembler time. These
actions have the effect of changing the object code  produced,  or
the  format of the listing.  Directives are scanned  exactly  like
executable  instructions and some may be preceded by a label  (for
some  it is obligatory) and may be followed by a comment.  If  you
put  a  label on a directive for which it  is  not  relevant,  the
result  will  be undefined but will usually result  in  the  label
being ignored.
     Each  directive will now be described in  turn.  Please  note
that  the case of a directive name is not important,  though  they
generally are shown in upper case. The use of angled brackets ( <> )
in descriptions denote optional  items,  ellipses  (  ...  )
denote repeated items.

ASSEMBLY CONTROL

END
     This directive signals that no more text is to be examined on
the current pass of the assembler. It is not obligatory.

INCLUDE filename
     This directive will cause source code to be taken from a file
on  disk  and assembled exactly as though it were present  in  the
text.  The  directive  must be followed by a  filename  in  normal
AmigaDOS format.
     If the filename has a space in it the name should be enclosed
in  single  or double quotes.  A drive  specifier,  directory  and
extension may be included as required, e.g.

     include b:constants/header.s

     Include  directives may be nested as deeply as memory  allows
and  if any error occurs when trying to open the file or read  it,
assembly will be aborted with a fatal error.
     If  no  drive or path name is specified,  that  of  the  main
source file will be used when trying to open the file.

     NOTE: The more memory the better, GenAm will read the whole of the
file in one go if it can and not bother to re-read the file during
pass 2.

INCDIR "directory"<,"directory" etc.>
     This directive specifies a list of directories that the include
directive should search in order to find each file. GenIm will append
each string onto the front of that given in the include directive. This
directive must appear before any include directives.

INCBIN    filename
     This  takes a given binary file and  includes  it,  verbatim,
into the output file.  Suggested uses include screen data,  sprite
date and ASCII files.
     The included data is forced to an even boundary and a single null
character is appended if the file is an odd number of bytes in length.

OPT       option <,option>...
     This  allows  control over various options within  GenAm  and
each one is denoted by a single character normally followed by a +
or - sign. Multiple options may be specified, separated by commas.
The allowed options are:

OPTION A - AUTOMATIC PC MODE ADDRESSING
     If OPT A+ is specified then GenAm will use PC mode addressing
where possible. For example:

          move.l    int_in,d0

will automatically be transformed into

          move.l    int_in(pc),d0

when assembled.

     Use of this option can significally reduce program size and
running time without a lot of extra typing. Please note however thit
it does not guarentee that the code generated will be position
independant.
     If you need to over-ride the automatic use of PC mode then use
the form (expression).l in a similar manner to that of short word
addressing as described above under labels and periods.
     So the example above could be forced to use absolutre addressing
by using the following:

move.l     (int_in).l,d0

    The default is A- when no such transformations are performed.

OPTION C - CASE SENSITIVITY AND SIGNIFICANCE.
     By default,  GenAm is sensitive to label case and labels  are
significant to 127 characters.  This can be overridden , using  C-
for case-sensitivity or C+ for case-insensitivity. The significan
ce  may be specified by specifying a decimal number between the  C
and  the sign,  for example C16+ denotes case  insensitive  labels
with  16 character significance.  This option may be used  at  any
time  in  a  program but normally only makes  sense  at  the  very
beginning of a source file.

OPTION D - DEBUGGING INFORMATION
     The  AmigaDOS  binary file format supports the inclusion of a
symbol hunk, which may be read by debuggers such  as
MONAm and  can be extremely useful when  debugging  programs.  By
default  this is switched off but it may be activated with D+  and
de-activated with D-. Normally all the relative symbols are included
in the file, but if OPT X+ is used in linkable mode then only the
exported (XDEF) symbols will be included.

OPTION L - LINKER MODE.
     The  default for GenAM is to produce executable code  but  L+
will  make it produce AmigaDOS linkable code, or L- will make it
revert to executable. This directive must be the very first line, in
the first text file.

OPTION M - MACRO EXPANSIONS.
     When an assembly listing is produced,  macro calls are  shown
in  the same form as in the source.  If you wish the  instructions
within  macros to be listed,  use M+,  while M- will  disable  the
option. You can use this directive as often as required. M- is the
default.

OPTION O - OPTIMISING.
     GenAM is capable of optimising certain statements to  faster
and  smaller versions.  By default all optimising is off but  each
type  can  be  abled and disabled as  required.  This  option  has
several forms:

OPT  O1+       will optimise backward branches to short if  within
               range, can be disabled with O1-.

OPT  O2+       will   optimise  address  register  indirect   with
               displacement addressing modes to addresss  register
               indirect,  if the displacemant evalues to zero, and
               can be disabled with O2-. For example,

          move.l   next(a0),d3

will be optimised to

          move.l   (a0),d3

If the value of next is zero.

OPT O+         will turn all optimising on.

OPT O-         will turn all optimising off.

OPT O1-, OPT O2-    will disable the relevant optimisation.

OPT OW-        will disable the warning messages generated by each
               optimisation, OW+ will enable them.

     If any optimising has been done during an assembly the number
of optimisations made and bytes saved will be shown at the end  of
assembly.

OPTION P - POSITION INDEPENDANT CHECKS.
     With  this  enabled with P+ GenAM will check  that  all  code
generated is position-independant,  generating errors on any lines
which require relocation.  It can be disabled with P- and defaults
to off.

OPTION S - SYMBOL TABLE
     When  a listing is turned on a symbol table will be  produced
at the end.  If you wish to change this S- will disable it,  while
S+ will re-enable it.  If you use this directive ore than once  the
last one will be taken into account.

OPTION T - TYPE CHECKING.
     GenST  can  often spot programming errors as  it  checks  the
types of certain expressions.  For some applications or styles  of
programming  this can be more of a hindrance than a  help.  So  T-
will  turn checks off.  T+ turning them back on.  For example  the
program segment

     main      bsr            initialise
               lea            main(a6),a0
               move.l         (main).w,a0

     will  normally  produce  an  error  as  main  is  a  relative
expression  where as the assembler expects an absolute  expression
in both cases.  However if this code is designed to run on another
68000  machine this may be perfectly valid,  so the type  checking
should be disabled.

OPTION U - UNDERLINES FOR LOCAL LABELS
     Option U+ changes the character that introduces local tables to
be underline (_) rather than dat (.). Usa this if you need to use
labels beginning with dot for non-local labels.

OPTION W - WARNINGS
     If  you wish to disable the warnings that GenST can  produce,
you can do so with W-.  To re-enable them use W+.  This  directive
can be used as often as required.

OPTION X - EXPORTDEBUG
     This is a special version of option D which only outputs the
exported (XDEFed) symbols when producing linkable code. See the D
option above.

OPTION SUMMARY
     The  defaults  are  shown  in  brackets  after  each  options
description;

A    automatic PC mode addressing
C    case-sensitivity and significance (C127+)
D    include debugging info, (D-)
L-   produce executable code (default)
L+   produce GST linkable code
M    expand macros enlisting (M+)
O    optimising control (O-)
P    position independant code checks (P-)
S    symbol table listing
T    type checking (T+)
W    warning control (W+)
X    export debug (X-)

For example -   opt  m+,s+,w-

will  turn macro expansion on,  enable the symbol table  list  and
turn warnings off.

<label> EVEN
     This  directive  will force the program counter to  be  even,
i.e.   word  aligned.   As  GenAM automatically  word-aligns  all
instructions (except DC.Bs and DS.Bs).  It should not be  required
very often but can be useful for ensuring buffers and strings  are
word-aligned when required

CNOP      offset,alignment
This  directive  will align the program counter  using  the  given
offset  and alignment.  An alignment of 2 means  word-aligned,  an
alignment of 4 means long-word-aligned and so on. The alignment is
relative to the start of the current section. For example,

          cnop   1,4

aligns  the  program  counter  a  byte  past  the  next  long-word
boundary.

     Some parts of the Amiga operating system require certain items to
be longword aligned and this can be achieved with:

          cnop   0,4

     The start of a program and of each section is always guaranteed
to be longword aligned.

<label>   DC.B      expression<,expression> ...
<label>   DC.W      expression<,expression> ...
<label>   DC.L      expression<,expression> ...

     These  directives define constants in memory.  They may  have
one or more operands,  separated by commas.  The constants will be
aligned  on  word boundaries for DC.W and DC.L no  more  than  128
bytes can be generated by a single DC directive.
     DC.B  treats  strings slightly different to those  in  normal
expressions.  While the rules described previously about quotation
marks still applies.  No padding of the bytes will occur,  and the
length of any string can be upto 128 bytes.
     Be very careful of spaces in any DC directives, as a space is
the delimiter before a comment. For example, the line

          dc.b      1,2,3 ,4

will only generate 3 bytes - the ,4 will be taken as a comment.

<label>   DS.B      expression
<label>   DS.W      expression
<label)   DS.L      expression

     These  directives  will  reserve  memory  locations  and  the
contents will be initialised to zeros. If there is a label then it
will be set to the start of the area defined,  which will be on  a
word  boundary  for  DS.W  and  DS.L  directives.   There  is   no
restriction  on the size though the larger the area the longer  it
will take to save to disk.

      For example, all of these lines will reserve 8 bytes of space,
in different ways :

          ds.b 8
          ds.w 4
          ds.l 2

<label>   DCB.B     number,value
<label>   DCB.W     number,value
<label>   DCB.L     number,value

     This directive allows constant blocks of data to be generated
of the size specified,  number specifies how many times the  value
should be repeated.

FAIL
     This directive will produce the error user error.  It can  be
used  for  such things as warning the programmer if  an  incorrect
number of parameters have been passed to a macro.

OUTPUT    filename
     This directive sets the normal output filename though can  be
overridden by specifying a filename at the start of  assembly.  If
filename starts with a period then it is used as an extension  and
the output name is built up as described previously.

__G2      (reserved symbol)
     This is a reserved symbol that can be used to detect  whether
GenST is being used to assemble a file using the IFD  conditional.
The  value of this symbol depends on the version of the  assembler
and is always absolute.

REPEAT LOOPS
     It  is  often  useful  to  be able  to  repeat  one  or  more
instructions  a  particular number of times and  the  repeat  loop
construct allows this.

<label>   REPT      expression
          ENDR

     Lines to be repeated should be enclosed within REPT and  ENDR
directives  and will be repeated the number of times specified  in
the expression. If the expression is zero or negative then no code
will be generated.  It is not possible to nest repeat  loops.  For
example

          REPT      512/4             copy a sector quickly
          move.l    (a0)+,(a1)+
          ENDR

     NOTE: Program  labels should not be define within repeat  loops
to prevent label defined twice errors.

LISTING CONTROL

LIST
     This  will  turn the assembly listing on during  pass  2,  to
whatever  device was selected at the start of the assembly (or  to
the  screen of None was initially chosen).  All  subsequent  lines
will be listed until an END directive is reached,  the end of  the
text is reached, or a Nolist directive is encountered.
     Greater  control  over  listing sections of  program  can  be
achieved using LIST+ or LIST- directives. A counter is maintained,
the state of which dictates whether listing is on or off.  A LIST+
directive  adds one to the counter and a LIST- subtracts  one.  If
the  counter  is zero or positive then listing is  on,  if  it  is
negative  then listing is off.  The default starting value  is  -1
(i.e.  listing  off)  unless  a  listing  is  specified  when  the
assembler was invoked,  when it is set to zero. This system allows
a  considerable  degree of control over listing  particularly  for
include  files.  The normal LIST directive sets the counter to  0,
NOLIST sets it to -1.

NOLIST
     This will turn off any listing during pass 2.

     When  a listing is requested onto a printer or to  disk,  the
output is formatted into pages,  with a header at the top of every
page.  The header itself consists of a line containing the program
title, date, time and page number, then a line showing the program
title,  then a line showing the sub-title,  then a blank line. The
date  format  will be printed in the  form  DD/MM/YY,  unless  the
assembler  is  running  on a US Atari ST,  then  it  is  MM/DD/YY.
Between  pages  a  form-feed character (ASCII  FF,  value  12)  is
issued.

PLEN      expression
     This  will  set the page length of the assembly  listing  and
defaults to 60. The expression must be between 12 and 255.

LLEN      expression
     This  will  set the line width of the  assembly  listing  and
defaults  to 132.  The value of the expression must be between  38
and 255.

TTL       string
     This  will set the title printed at the top of each  page  to
the  given string,  which may be enclosed in  single  quotes.  The
first TTL directive will set the title of the first printed  page.
If  no  title is specified the current include file name  will  be
used.

SUBTTL    string
     Sets  the  subtitle printed at the top of each  page  to  the
given string,  which may be enclosed in single quotes.  The  first
such directive will set the sub-title of the first printed page.

SPC       expression
     This  will  output  the number of blank lines  given  in  the
expression in the assembly listing, if active.

PAGE
     Causes a new page in the listing to be started.

LISTCHAR  expression<,expression> ...
     This will send the characters specified to the listing device
(except  the  screen)  and is intended for doing  things  such  as
setting  condensed mode on printers.  For example,  on Epsons  and
compatibles the line

          listchar  15

will set the printer to 132-column mode.

FORMAT    parameter<,parameter> ...
     This allows exact control over the listed format of a line of
source  code.  Each parameter controls a field in the listing  and
must consist of a digit from 0 to 2 inclusive followed by a +  (to
enable the field) or a - (to disable it):

0    line number, in decimal
1    section name/number and program counter
2    hex data words, up to 10 words unless printer is less than 80
     characters wide, when up to three words are listed.

LABEL DIRECTIVES

label     EQU       expression

     This directive will set the value and type of the given label
to  the  results of the expression.  It may  not  include  forward
references,  or  external  labels.  If there is any error  in  the
expression,  the  assignment  will  not  be  made.  The  label  is
compulsory and must not be a local label.

label     =         expression

Alternate form of EQU statement

label     EQUR      register

     This  directive  allows  a data or  address  register  to  be
referred  to  by  a  user-name,  supplied as  the  label  to  this
directive.  This is known as a register equate.  A register equate
must be defined before it is used.

label     SET       expression

     This is similar to EQU,  but the assignment is only temporary
and  can  be  changed with a  subsequent  SET  directive.  Forward
references  cannot  be used in the expression.  It  is  especially
useful for counters within macros, for example, using a line

zcount    set       zcount+1

(assuming zcount is set to 0 at the start of the source).  At  the
start of pass 2 all SET labels are made undefined, so their values
will always be the same on both passes

label     REG       register-list

     This  allows  a symbol to be used to denote a  register  list
within MOVEM instructions,  reducing the likelihood of having  the
list at the start of a routine different from the list at the  end
of the routine. A label defined with REG can only be used in MOVEM
instructions.

<label>   RS.B      expression
<label>   RS.W      expression
<label>   RS.L      expression

     These  directives  let you set up lists of  constant  labels,
which is very useful for data structures and global variables  and
is best illustrated by a couple of examples
     Let's  assume you have a data structure which consists  of  a
long word,  a byte and another long word,  in that order.  To make
your code more readable and easier to update should the  structure
change, you could use lines such as:

          rsreset
d_next    rs.l      1
d_flag    rs.b      1
d_where   rs.l      1

and then you could access them with lines like

          move.l    d_next(a0),a1
          move.l    d_where(a0),a2
          tst.b     d_flag(a0)

As  another  example  let's assume you are  referencing  all  your
variables  off register A6 (as done in GenAM and MonAM) you  could
define them with lines such as

onstate   rs.b      1
start     rs.l      1
end       rs.l      1

you then could reference them with lines such as

          move.b    onstate(a6),d1
          move.l    start(a6),d0
          cmp.l     end(a6),d0

     Each such directive uses its own internal counter, which is reset
to 0 at the beginning of each pass. Every time the assembler comes
across  the directive it sets the label according to  the  current
value  (with word alignment if it is .W or .L) then increments  it
according to the size and magnitude of the directive. If the above
definitions  were  the first RS directives,  onstate would  be  0,
start would be 2 and end would be 6.

RSRESET
     This directive will reset the internal counter as used by the RS
directive.

RSSET     expression
     This allows the RS counter to be set to a particular value.

__RS      (reserved symbol)
     This is a reserved symbol having the current value of the RS
counter.

CONDITIONAL ASSEMBLY
     Conditional  assembly  allows  the  programmer  to  write   a
comprehensive  source  program  that can  cover  many  conditions.
Assembly  conditionals  may  be  specified  through  the  use   of
arguments,  in the case of macros,  and through the definition  of
symbols  in EQU or SET directives.  Variations in these  can  then
cause  assembly  of only those parts necessary for  the  specified
conditions.
     There   are  a  wide  range  of  directives  concerned   with
conditional assembly. At the start of the conditional blocks there
must  be  one of many IF directives and at the end of  each  block
there must be an ENDC directive.  Conditional blocks may be nested
up to 65535 levels.
     Labels  should not be placed on IF or ENDC directives as  the
directives will be ignored by the assembler.

          IFEQ      expression
          IFNE      expression
          IFGT      expression
          IFGE      expression
          IFLT      expression
          IFLE      expression

     These directives will evaluate the expression, compare it with
zero and then turn the conditional assembly on or off depending on
the  result.  The  conditions  correspond  exactly  to  the  68000
condition codes.  For example, if the label DEBUG had the value 1,
then with the following code,

          IFEQ DEBUG
logon     dc.b      'enter a command:'.0
          ENDC
          IFNE DEBUG
          opt       d+        labels please
logon     dc.b      'Yeah, gimme man:',0
          ENDC

the first conditional would turn assembly off as 1 is not EQ to 0,
while the second conditional would turn it on as 1 is NE to 0.

     NOTE: IFNE corresponds to IF in assemblers with only one
conditional directive.
     The  expressions  used in these conditional  statements  must
evaluate correctly.

IFD       label
IFND      label
     These  directives  allow  conditional  control  depending  on
whether a label is defined or not.  With IFD, assembly is switched
on if the label is defined, whereas with IFND assembly is switched
on  if the label is not defined.  These directives should be  used
with  care otherwise different object codes could be generated  on
pass  1 and pass 2 which will produce incorrect code and  generate
phasing errors. Both directives also work on reserved symbols.

IFC       'string1','string2'
     This  directive will compare two strings,  each of which  must
be surrounded  by single quotes.  If they are identical  assembly  is
switched  on,  else  it i switched off.  The  comparison  is  case
sensitive.

IFNC      'string1','string2'
     This directive is similar to the above, but only switches
assembly on  if  the strings are not identical.  This may at  first
appear somewhat useless, but when one or both of the parameters are
macro parameters it can b every useful, as shown in the next section.

ELSEIF
     This  directive toggles conditional assembly from on  to  off,
or vice versa.

ENDC
     This  directive  will terminate the current level  of
conditional assembly.  If  there  are more IF's then ENDC's an error
will be reported at the end of assembly.

IIF       expression   instruction
This  is  a  short form of the IFNE directive  allowing  a  single
instruction  or directive to be assembled conditionally.  No  ENDC
should be used with IIF directives.

MACRO OPERATIONS
     GenAM fully supports Motorola-style macros, which together with
conditional  assembly  allows you greatly  to  simplify  assembly-
language programming and the readability of your code.
     A macro is a way for a programmer to specify a whole sequence
of  instructions  or  directives  that  are  used  together   very
frequently. A macro is first defined, then its name can be used in
a macro call like a directive with up to 36 parameters.

label     MACRO
     This starts a macro definition and causes GenAM to copy all
following  lines  to  a macro buffer until an  ENDM  directive  is
encountered. Macro definitions may not be nested.

ENDM
     This terminates the storing of a macro definition, after a  MACRO
directive.

MEXIT
     This stops prematurely the current macro expansion and is best
illustrated by the INC example given later.

NARG      (reserved label)
     This is not a directive but a reserved symbol, Its value is  the
number  of parameters passed to the current macro,  or 0  if  used
when not within any macro.  If GenAM is in the case sensitive mode
then the name should be all upper-case.

MACRO PARIMETERS
     Once a macro has been defined with the Macro directive it can
be invoked by using its name as a directive,  followed by upto  36
parameters.  In the macro itself the parameters may be referred to
by  using a backslash character (\) followed by  an  alpha-numeric
(1-9,  A-Z  or  a-z)  which will be  replaced  with  the  relevant
parameter when expanded or with nothing if no parameter was given.
There  is  also the special macro parameter \0 which is  the  size
appended to the macro call and defaults to W if none is given.  If
a  macro  parameter  is  to include  spaces  or  commas  then  the
parameter should be enclosed in between < and > symbols;  in  this
case  a  >  symbol  may  be  included  within  the  parameters  by
specifying >>.
     A special form of macro expansion allows the conversion of  a
symbol to a decimal or hexadecimal sequence of digits,  using  the
syntax \<symbol> or \$<symbol>, the latter denoting hex expansion.
The symbol mast be defined and absolute at the time of expansion.
     The  parameter \@ can be useful for generating unique  labels
with each macro call and is replaced when the macro is expanded by
the  sequence  _nnn where nnn is a number which increases  by  one
with  every  macro call.  It may be expanded up to  5  digits  for
very large assemblies.
     A true \ may be included in a macro definition by specifying \\.

     A  macro  call  may  be  spread  over  more  than  one  line,
particularly  useful for macros with large numbers of  parameters.
This  can  be  done  by ending a macro  call  with  a  comma  then
starting  the next line with an & followed by tabs or spaces  then
the continuation of the parameters.
     In the assembly listing the default is to show just the macro
call and not the code produced by it. However, macro expansion
listings can  be  switched on and off using the OPT M  directive
described previously.
     Macro  calls may be nested as deeply as memory  permits,
allowing recursion if required.
     Macro  names are stored in a separate symbol table to normal
symbols so will not clash with similarly named routines,  and  may
start with a period.

MACRO EXAMPLES

EXAMPLE 1 - CALLING A LIBRARY
     As the first example, a common way of calling an Amiga library
routine is:

        save register a6
        load a6 from a library pointer
        do a jsr with offset
        restore a6

     A macro to follow the above specifications could be:

call_lib MACRO
         move.l   a6,-(sp)
         move.l   \2,a6       get lib pointer
         jsr      _LVO\l(a6)  call it
         move.l   (sp)+,a6    restore
         ENDM

     The directives are in capitals only to make them stand  out:  they
don't have to be.  If you wanted to call this macro to use the DOS
function Output the code would be:

call_lib Output,_DOSbase

     When this macro call is expanded, \1 is replaced with Output and
\2 is replaced with _DOSbase. \0, if it occurred in the macro, would
be W as no size  is given on the call.  So the above call would be
assembled as:

        move.l  a6,-(sp)
        move.l  _DOSbase,a6     get lib pointer
        jsr     _LVOOutput(a6)  call it
        move.l  (sp)+,a6        restore a6

EXAMPLE 2 - AN INC INSTRUCTION
     The 68000 does not have the INC instruction like other
processors but the same effect can be achieved using an ADDQ #1
instruction. A macro may be used to do this, like so:

inc       MACRO
          IFC       '','\1'
          fail      missing parameter!
          MEXIT
          ENDC
          addq.\0   #1,\1
          ENDM

An example call would be

          inc.1     a0

which would expand to

          addq.1    #1,a0

     The macro starts by comparing the first parameter with an empty
string and causing an error message to be issued using FAIL if  it
is equal.  The MEXIT directive is used to leave the macro  without
expanding the rest of it.  Assuming there is a non-null parameter,
the next line does the ADDQ instruction, using the \0 parameter to
get the correct size.

EXAMPLE 3 - A FACTORIAL MACRO
     Although  unlikely actually to be used as it stands, this macro
defines  a  label to be the factorial of a number.  It  shows  how
recursion  can work in macros.  Before showing the  macro,  it  is
useful to examine how the same thing would be done in a high level
language such as Pascal.

function  factor(n:integer):integer;
begin
          if n>0 then
                    factor:=n*factor(n-1)
          else
                    factor:=1
end;

     The macro definition for this uses the SET directive to do the
multiplication n*(n-1)*(n-2) etc. in this way

*    parameter 1= label,   parameter 2= 'n'
factor    MACRO
          IFND      \1
\1        set       1         set if not yet defined
          ENDC
          IFGT      \2
          factor    \1,\2-1   work out next level down
\1        set       \1*(\2)   n = n * factor(n-1)
          ENDC
          ENDM
*    a sample call
          factor test,3

     The net result of the previous code is to set test to 3! (3
factorial). The reason the second set  has (\2) instead of just \2
is  that  the  parameter  will  not  normally  be  just  a  simple
expression,  but a list of numbers separated by minus signs, so it
could assemble to:

test      set       test*5-1-1-1

(i.e. test*5-3) instead of the correct

test      set       test*(5-1-1-1)

(i.e. test *2)

EXAMPLE 4 - CONDITIONAL RETURN INSTRUCTION
     The 68000 lacks the conditional return instruction found on other
processors,  but macros can be defined to implement them using the
\@ parameter. For example, a return if EQ macro could look like:

rtseq     MACRO
          bne.s     \@
          rts
\@
          ENDM

      The \@ parameter has been used to generate a unique label every
time  the macro is called,  so will generate in this  case  labels
such as _002 and _017.

EXAMPLE 5 - NUMERIC SUBSTITUTION
     Suppose you have a constant containing the version number of
your program and wish it to appear as ASCII in a message:

showname  MACRO
          dc.b      \1,'\<version>',0
          ENDM
          .
          .
version   equ       42
          showname  <'Real Ale Search Program v'>

will expand to the line

          dc.b      'Real Ale Search Program v','42',0

Note  the  way  the string parameter is enclosed in  <  >s  as  it
contains spaces.

EXAMPLE 6 - COMPLEX MACRO CALL
     Suppose your program needs a complicated table structure which
can have a varying number of fields.  A macro can only be written  to
using those parameters that are specified,  for example:

table_entry         macro
          dc.b      .end\0-*            length byte
          dc.b      \1                  always
          IFNC      '\2',''
          dc,w      \2,\3               2nd and 3rd together
          ENDC
          dc.l      \4,\5,\6,\7
          IFNC      '\8',''
          dc.b      '\8'                text
          ENDC
          dc.b      \9
.end\@    dc.b      0
          ENDM

* a sample call
          table_entry                   &42,,,t1,t2,t3,t4,
&                                       <Enter Name:>,%0110

NOTE: THE NEXT 2 PAGES ARE MISSING FROM MY PHOTOCOPY (THANX REB!) SO
I'LL HAVE TO IMPROVISE.. I'LL MARK WHERE IT'S BACK FROM THE MANUAL.

     This is a non-trivial example of how macros can make a
programmer's  life so much easier when dealing with  complex  data
structures.  In  this  case the table consists of a  length  byte,
calculated in the macro using \@,  two optional words, four longs,
an optional string, a byte, then a zero byte. The code produced in
this example would be :

          dc.b      .end_001
          dc.b      $42
          dc.l      t1,t2,t3,t4
          dc,b      'Enter Name:'
          dc,b      %0110
.end_001  dc.b      0

OUTPUT FILE FORMATS
     GenAM is very flexible in terms of output file formats. These
are detailed in this section together with notes on the advantages
and  disadvantages  of each.  Certain  directives  take  different
actions, depending on what output file format is specified.

     The exact details of using each format will now be described.

EXECUTABLE FILES
     These  are  directly  executable,   for  example,  by  double
clicking  from the workbench, or from the CLI. The file may include
relocation information  and/or symbolic information.

ADVANTAGES
     true BSS sections, reduced development time.

DISADVANTAGES
     messy if more than one programmer.

GST LINKABLE FILES
     When  writing  larger programs,  or  when  writing  assembly
language  modules  for  use  from  the  high  level  language,   a
programmer needs to generate a linkable file.  The GST link format
is  supported  by  most of the high level  languages  produced  in
Britain as well as others,  for example HiSoft Basic,  Lattice  C,
Prospero  Fortran and Prospero Pascal.  GST format files  normally
have the extension .BIN.

ADVANTAGES
     Great  degree of freedom - imported labels  can  be
used  practically anywhere including within arbitrary  expressions,
libraries can be created from the assembler,  import methods means
the assembler can detect type conflicts.

DISADVANTAGES
     Library format means selective library linking  can
be  slow,  true AmigaDOS sections not supported as standard.

CHOOSING THE RIGHT FILE FORMAT
     If  you wish to link with a high level language  there  isn't
usually  much  choice  -  you have  to  use  whichever  format  is
supported by the language.
     If  you  are writing entirely in assembly language  then  the
normal  choice has to be executable - it is fast to  assemble,  no
linking  required,  and  allows assembly to memory  for  decreased
development time.
     If  you  are writing a larger program,  say bigger  than  32k
object,  or writing a program as a team,  then linkable code often
makes  most sense.  We recommend GST-linkable over DRI because  of
the much greater flexibility of the format.

OUTPUT FILE DIRECTIVES
     This section details those directives whose actions depend on
the  output  file format chosen.  The file format  itself  can  be
chosen by one of the following methods; command line options using
GENST2.TTP;  clicking on the radio buttons in the Assembly Options
dialogue box from the editor,  or with the OPT L directive at  the
beginning of the source file.

Icons are used to denote those sections specific to a file format,
viz

*EXEC*    Executable-code, also assembled to memory code.

*GST*     GST-linkable code

*DRI*     DRI-linkable code.

BACK TO THE MANUAL, HOPE I GOT IT RIGHT, shit! THE NEXT BIT IS VERY
DIFFERANT SO THE ABOVE IS PROBABLY WRONG!           PARASITE 4.26am

SECTIONS

SECTION string<,type>
     This  defines a switch to the named section and optionally
defines it's type. A program may consist of several sections which
will be concentrated together with other sections of the same name in
the final executable file. This will use the supplied string and type
as the section name and type of this section (of hunk) respectivly.
Each can be up to 32 characters long and should not include tabs or
spaces or be enclosed in quotes. The casing of the name is
significant. You may have many SECTION directives in your program.
     The type can be one of the following (in upper or lower case):

CODE    code section, public memory
CODE_F  code section, Fast memory
CODE_C  code section, chip memory
DATA    data section, public memory
DATA_F  data section, fast memory
DATA_C  data section, chip memory
BSS     BSS section, public memory
BSS_F   BSS section, fast memory
BSS_C   BSS section, chip memory

     CODE sections are used for executable instructions, DATA sections
for initialised data (constants), and BSS for un-initialised data. BSS
sections  have the advantage that they take no disk space - only the
length of the BSS section is stored. If you define a section to be BSS
you can only use the directive to produce code - any other code
generating instructions will cause a binary file i/o error.
     NOTE: Do not use types requesting chip or fast memory, with
versions prior to version 2.3 of the Alink linker - these versions
will crash!

CODE/DATA/BSS
     These directives are supported for compatability with the Amiga
macro assembler. They are the same as specifying the directive as the
section name and type.

IDNT string
     This will use the supplied name as the hunk unit name for this
section, It can be up to 32 characters long and should not include
tabs or spaces or be enclosed in quotes.

IMPORTS AND EXPORTS
     With both linkable types of program it is crucial to be  able
to import and export symbols,  both relative symbols (i.e. program
references) and absolute symbols (i.e.  constants). The AmigaDOS
linker format does not distinguish between these types; however by
specifying the type when importing, the assembler can type check,
often  finding programming errors that would otherwise be missed.

XDEF      export<,export>...
     This  defines  labels  for  export  to  other  programs   (or
modules).  If any of the labels specified are not defined an error
will occur. It is not possible to export local labels.

EXEC
     This directive is ignored

XREF      import<,import>...
XREF.L    import<,import>...
     This  defines  labels to be imported from other  programs  or
modules.  If any of the labels specified are defined an error will
occur.  The  normal  XREF  statement should be used  to  import  a
relative label (i.e.  program reference),  while XREF.L should  be
used to import absolute labels (i.e. constants). If you do not type
your imports you should turn type-checking off using OPT T-
     Importing a label more than once will not produce an error.

EXEC
     This directive is ignored

USING IMPORTS IN EXPRESSIONS

EXEC
     There are no imports! However referances to labels in other
sections are subject to the limitations described below.

LINK
     Imports  may be used in expressions but only one  import
per  expression is allowed.  The results of an expression with  an
import  in must be of the form import+number  or  import-number.
Imports can be combined with arbitrarily complex  expressions,  so
long as the complex expression lexically precedes it, for example

          move.l    3+(1<<count+5)+import

EXPRESSION     GST            DRI       EXAMPLE
byte           Y              N         move.b #test,do
word           Y              Y         move.w test(a3),d0
long           Y              Y         move.l test,d0

COMMENT   comment string

This directive is ignored at present

ORG       expression
     This will make the assembler generate position dependant code
and  set  the program counter to the given  value.  Normal AmigaDOS
program,s do not need an ORG statement even if position dependant.
It  is included to allow code to be generated for the ROM port  or
for other 68000 machines.  More than one ORG statement is  allowed
in a source file but no padding of the file is done.

EXEC
     It  should  be used with great care as the  binary  file
generated will probably not execute correctly when double clicked.
as  no  relocation information is written  out.  The  binary  file
produced  has  the standard AmigaDOS header at  the  front,  but  no
relocation information.

LINK
     This directive is not allowed.

OFFSET    <expression>
     This  switches  code  generation  to  a  special  section  to
generate absolute labels. The optional expression sets the program
counter for the start of this section. No bytes are written to the
disk and the only code generating directive allowed is DS.  Labels
defined in this section will be absolute.  For example,  to define
some of the system variables of the ST. (This is in the AMIGA
manual!);

          offset    $400
etv_timer           ds.l      1         will be $400
etv_critic          ds.l      1         404
etv_term            ds.l      1         408
ext_extra           ds.l      5         40C
memvalid            ds.l      1         420
memcntlr            ds.w      1         424

__LK      (reserved symbol)
     This  is a reserved symbol that can be used to  detect  which
output  mode  is specified.  The value of this symbol  is  alwayus
absolute and one of the following:

3 linkable
4 executable

      Values 0-2 are reserved for the production of ST code; other
values and the high word are reserved for future expansion.

RETURN CODES
     When using the stand alone assembler from within batch files or
make files, it's return code can be used to determine  the success of
the assembly. Values returned are:

100+ initialisation failure
 20  fatal error
  5  warnings
  0  OK

DIRECTIVE SUMMARY

ASSEMBLY CONTROL
END       terminate source code
INCLUDE   read source file from disk
INCBIN    read binary file from disk
OPT       option control
EVEN      ensure PC even
CNOP      align PC arbitrarily
DC        define constant
DS        define space
DCB       define constant block
FAIL      force assembly error

REPEAT LOOPS
REPT      start repeat block
ENDR      end repeat block

LISTING CONTROL
LIST      enable list
NOLIST    disable list
PLEN      set page length
LLEN      set line length
TTL       set title
SUBTTL    set sub-title
PAGE      start new page
LISTCHAR  send control character
FORMAT    define listing format

LABEL DIRECTIVES
EQU       define label value
EQUR      define register equate
SET       define label value temporarily
REG       define register list
RS        reserve space
RSRESET   reset RS counter
RSSET     set RS counter

CONDITIONAL ASSEMBLY
IFEQ      assemble if zero
IFNE      assemble in non-zero
IFGT      assemble if greater than
IFGE      assemble if greater than or equal to
IFLT      assemble if less than
IFLE      assemble if less than or equal to
IFD       assemble if label defined
IFND      assemble if label not defined
IFC       assemble if strings same
IFNC      assemble if strings different
ELSEIF    switch assembly state
IIFC      immediate IF

MACROS
MACRO     define macro
ENDM      end macro definition

OUTPUT FILE DIRECTIVES
MODULE    start new module
SECTION   switch section
XDEF      define label for export
XREF      define label for import
COMMENT   send linker comment
ORG       set absolute code generation
OFFSET    define offset table

RESERVED SYMBOLS
NARG      number of macro parameters
__G2      internal version number
__RS      RS counter
__LK      output file type

BLINK LINKER
     This version of BLINK is a public domain limker designed as a
replacement for the standard AmigaDOS linker, Alink. The program has
many powerful features, but in the simplest case the command line is

blink (from) <infile.o> [<infile2.o>...] [ TO <outfile>]

which specifies one or more input files and an output file. Normally
all sections will be placed in seperate hunks, but they can be forced
into one hunk by specifying SMALLCODE or SMALLDATA on the command
line. For example;

blink test.o

will link test.o into the file test

blink FROM start.o middle.o end.o TO total

will link the specified three files into total

blink FROM start.o middle.o end.o TO total SMALLCODE

as above but coalescing for BLink are contained in a  file on disk 2,
which can be read on screen or printed out in the usual manor.

NOW LOAD PART 2...