C/C++ Interactive Reference Guide

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Text File | 1990-05-16 | 9.8 KB | 472 lines

AS8, a Z8 Crossassembler ======================== by: H.-G. Willers Gartenstrasse 11 D-8047 Karlsfeld WEST GERMANY This document dated 11-jan-90 Intro ===== This document briefly describes the features of my crossassembler for the Z8 microprocessor, called AS8. This assembler is based on some code found in a crossassembler for the Z80 microprocessor as published on the DECUS tape 11-SP-18. The code was polished up (e.g. adding a hashtable for the symbols instead of linear search) and many bugs were fixed. The resulting code acts as a skeleton for my assemblers like this one: AS8. The source code was compiled, using: o Mark Williams Let's C (Vers. 3.0.2) o Microsoft QuickC (Vers. 1.01) o System 5.3 UNIX C for 68020 o Interactive UNIX 386 3.2 2.1 To compile and link under Mark Williams C the file 'time.c' contains some hacks to simulate the missing library functions. The code is provided on an 'as is' basis. No responsibility for any malfunction of the assembler per se or any assembled program can be taken. You use it at your own risk. Please send comments and improvements to the author at the above address. Commandline Syntax ================== AS8 is invoked by the following commandline: as8 [-nl] sourcefile.ext The options mean: -l generates a listing named sourcefile.l -n do not generate an object file In the process of producing a name for the object file or the listing file the extension of the sourcefile is stripped. Any possible restrictions of filename use in a given operating system may apply. Source Syntax ============= The syntax of a source line for AS8 is as follows: label: opc src, dst / comment The 'label' is optional; if used, it must be followed by a colon. 'Opc' is the memonic representation for the instruction to be used. The source and destination operands are written as source first, then destination. Comments are introduced by the character '/'. Multiple statements per line are separated by ';', for example: nop ; nop ; nop Symbols ======= A symbol in as8 is a entity with a label set by a label or a direct assignment. The number of characters per symbol is 33 as distributed. It can be changed by adjusting the defined constant 'NCPS' to the desired value. Symbols can consist of the characters of the ASCII character set, but must begin with either a-z, A-Z, or the characters '.' or '_' (see the routine 'isidc(c)' ). Local Labels ============ There are 9 local labels: 1 - 9. references in the forward direction are indicated by a 'f', appended to the label number, references backwards are indicated by a trailing 'b'. For example: 1: nop sob w16,1b / label 1 backwards ... call 2f / label 2 forward ... 2: ret Each local label is reassigned to its new value when reused. Number Representation ===================== The default radix is decimal. The allowed digits range from 0 - 9. Base 16 numbers (hex) are denoted by a leading '0x'. For example: 0x20 is the same as 32. Base 8 numbers (octal) are denoted by a leading '0'. For example: 012 is the value of the ascii character CR. Base 2 numbers are preceeded by a '0B'. For example: 0B01010101 is the same as 0x55. Literals ======== Literal constants are enterd by the character ' , followed by the desired ASCII character. Expressions =========== Expressions are made up from numbers (or symbols) and arithmetic operators. Expression evaluation is done from left to right. This order can be changed by parenthesis with '[ .. ]'. The binary arithmetic operators are + , -, *, and %. The operator '%' in AS8 means / ( because comments are introduced by '/' ). The bitwise logical operators are & bitwise AND | bitwise inclusive OR ^ bitwise exclusive OR > right shift < left shift The following unary operators are supported: - two's complement ! one's complement Pseudo Operators ================ .byte symbol Generates one byte consisting of the value of 'symbol'. Example: .byte 0x20 / one byte (ascii space) .word symbol Generates one word consisting of the value of 'symbol'. The word is generated with the byte ordering of the Z8: nameley the upper 8 bits first (big endian byte ordering). Example: .word 0x1000 / generates the bytes 0x10 and 0 .ascii string Generates the named string as a sequence of ascii characters. The first character of the string is taken as a terminator. The string ends, when the terminator is found again. Example: .ascii "Hi there!" / ascii string .asciz string Generates the named string as a sequence of ascii characters. The string is followed by a null-character. The first character of the string is taken as a terminator. The string ends, when the terminator is found again. Example: .asciz "Hi there!" / ascii string with trailing zero .blkb count [, value] Space for 'count' bytes is left free. If the optional 'value' is not given, null bytes are taken for filling; bytes with the 'value' are taken otherwise. Examples: .blkb 100, 0x20 / 100 (decimal) bytes of content 0x20 / are filled up .blkb 0x1000 / 4096 bytes of content 0 .page The listing is advanced by one page. .title string The title line for the listing is set. The string starts with a terminator, which also end the string. Example: .title "simple demo" .hlist Sets the radix for number output in the listing to hex. .olist Sets the radix for number output in the listing to octal. .list Starts listing generation. This is the default state. .nlist Stops listing generation. .end symbol The entrypoint of the loaded program is set to 'symbol'. The start record of the produced intel-hex-tape is set to this value. Example: .end _main / program starts at _main Location Counter ================ The location counter is set by the assignment of '.' to the desired value. Example: . = 0x1000 / sets the location counter / to 0x1000 Addressing Modes ================ (See file z8tst.z8 for clarification) Register: r0 - r255 Working Register: w0 - w15 Register Indirect: e.g. ... (r0) Working Register Ind.: e.g. ... (w6) Indexed: e.g. mov r100(w0),w1 Immediate: e.g. add $1,w0 Direct, relative indicated by a label Instruction Description ======================= AS8 ZILOG switch in 'xasm' base opcode --- ----- ---------------- ccf ccf S_OP0 0xef di di S_OP0 0x8f ei ei S_OP0 0x9f reti iret S_OP0 0xbf nop nop S_OP0 0xff rcf rcf S_OP0 0xcf ret ret S_OP0 0xaf scf scf S_OP0 0xdf srp srp S_OP2 0x31 clr clr S_OP3 0xb0 com com S_OP3 0x60 da da S_OP3 0x40 dec dec S_OP3 0 pop pop S_OP3 0x50 push push S_OP3 0x70 rl rl S_OP3 0x90 rlc rlc S_OP3 0x10 rr rr S_OP3 0xe0 rrc rrc S_OP3 0xc0 sra sra S_OP3 0xd0 swap swap S_OP3 0xf0 call call S_OP4 jmp jp DA S_OP5 0x8d jcs jp c,DA S_OP5 0x7d jcc jp nc,DA S_OP5 0xfd jeq jp z,DA S_OP5 0x6d jne jp nz,DA S_OP5 0xed jpl jp pl,DA S_OP5 0xdd jmi jp mi,DA S_OP5 0x5d jov jp ov,DA S_OP5 0x4d jnov jp nov,DA S_OP5 0xcd jge jp ge,DA S_OP5 0x9d jlt jp lt,DA S_OP5 0x1d jgt jp gt,DA S_OP5 0xad jle jp le,DA S_OP5 0x2d juge jp uge,DA S_OP5 0xfd jult jp ult,DA S_OP5 0x7d jugt jp ugt,DA S_OP5 0xbd jule jp ule,DA S_OP5 0x3d br jr DA S_OP6 0x8b bcs jr c,DA S_OP6 0x7b bcc jr nc,DA S_OP6 0xfb beq jr z,DA S_OP6 0x6b bne jr nz,DA S_OP6 0xeb bpl jr pl,DA S_OP6 0xdb bmi jr mi,DA S_OP6 0x5b bov jr ov,DA S_OP6 0x4b bnov jr nov,DA S_OP6 0xcb bge jr ge,DA S_OP6 0x9b blt jr lt,DA S_OP6 0x1b bgt jr gt,DA S_OP6 0xab ble jr le,DA S_OP6 0x2b buge jr uge,DA S_OP6 0xfb bult jr ult,DA S_OP6 0x7b bugt jr ugt,DA S_OP6 0xbb bule jr ule,DA S_OP6 0x3b sob djnz wr,RA S_OP7 0x0a add add S_OP8 adc adc S_OP8 0x10 sub sub S_OP8 0x20 sbc sbc S_OP8 0x30 or or S_OP8 0x40 and and S_OP8 0x50 tcm tcm S_OP8 0x60 tm tm S_OP8 0x70 cmp cmp S_OP8 0xa0 xor xor S_OP8 0xb0 mov ld dst,src S_OP9 incw incw S_OP10 0xa0 decw decw S_OP10 0x80 inc inc S_OP11 0x20 dec dec S_OP12 movp ldc 'move from/to program memory' movd lde 'move from/to data memory' movpi ldci 'move from/to prog. mem autoincr. movdi ldei 'move from/to data mem autoincr.' Error Messages ============== Errors in the source code are flagged in the listing and in the terminal output by a one letter indicator. This is a list of the error indicators: a assembly error o branches out of range o 'srp' with wrong value o illegal addressing modes e argument not even (e.g. working reg. pair) m symbol multiply defined o undefined opcode name p phase error: labels do not have the same values in pass1 and pass2 of assembly q questionable syntax: o digit without ':' o .ascii or .asciz directive with no args o '[' and ']' not paired r types of arithmetic expression do not match t value of a byte to be output is out of range u symbol undefined z object buffer overflow Disclaimer ========== The original source code (Z80 crossassembler as found on DECUS 11-SP-18) is to the best of my knowledge in the public domain. My software for AS8 (opcode handling, misc. changes) is hereby released into the public domain. All registered trade marks belong to their owners.