Oakland CPM Archive/oakcpm.iso/cpm/dskbuf/ramdrv5.mqc/RAMDRV5.MAC

Text File | 1985-02-10 | 14.6 KB | 572 lines

    TITLE    RAMDRIV5.MAC
;
;***********************************************************************
;
;    RAMDRIV - A program that permits extended memory to function as
;    a fast disk drive.  This program does not require modification
;    of the existing BIOS.
;
;    Copyright 1982, by
;    Herbert B. Shore
;    Department of Physics
;    San Diego State University
;    San Diego, CA 92182
;    [phone]
;
;    Released to the public domain for non-commercial use.
;
;    RAMDRIV has been extensively modified by Paul J. Gans.  Changes
;    are copyright (c) by Paul J. Gans, Department of Chemistry, New
;    York University, New York, NY  10003 [phone]
;
;    New or modified features include:
;
;    For RAMDRIV5:
;
;    1.  Code has been converted to Z80 code throughout.
;    2.  The target assembler is now Microsoft's M80.
;    3.  The code is now self-loading.  The original RAMLD program is
;        no longer required.
;    4.  It is no longer required to have contiguous memory banks of
;        the same size.  Available memory is controlled by the
;        BLEN table described below.
;    5.  Track size is now a variable multiple of 1K and can be
;        changed through an equate.
;    6.  The original ALV parameter has been dropped in favor of
;        TRAKLEN, the number of kilobytes per track.
;    7.  The DRAM parameter has been dropped.  Extended (bank)
;        addresses are now contained in the BLEN table.
;    8.  The program now uses both the directory buffer and the host
;        buffer in the local BIOS instead of its own buffer.
;        This requires that the user know the addresses of both
;        of these buffers in his or her BIOS.  To accomodate
;        those who choose not to use the BIOS buffers, two DS
;        definitions are required a few lines after the label
;        WBOOT1.  The proper spot is commented in the code
;        below.
;
;
;    INSTALLATION of RAMDRIV5:
;
;    RAMDRIV assumes that the user's system has "extra" memory
;    available beyond the normal 64K maximum directly addressable
;    in Z80 systems.  This memory may be either "bank select" or
;    S-100 extended addressing.
;
;    RAMDRIV is installed by setting a number of equates and by
;    properly configuring the BLEN table located near the end of
;    the code.  After the proper values have been set by equates and
;    the BLEN table has been set up, the code should be assembled
;    using M80.  The commands for so doing are:
;
;    >M80 =RAMDRIV5/L    <== /L optionally produces a .PRN file
;    >L80 /P:100,RAMDRIV5,RAMDRIV5/N/E
;
;    The equates for DIRBUF and RAMBUF must be set to reflect the
;    location of these buffers in the user's BIOS.  If this is not
;    feasible, see the comments at the label WBOOT1.
;
;    Equates that must be set are defined and explained below.
;
;    In normal use the user must also configure the BLEN table for
;    his or her system and recompile.  There is one BLEN table entry
;    for each bank of memory to be used by RAMDRIV.  It is assumed
;    that each of these banks starts at address 0000 and proceeds
;    upward to some value without any holes.  It is also assumed that
;    at least the upper 1K of system memory is global, thus no bank
;    can exceed 63K.
;
;    A BLEN table entry consists of two bytes for each bank of memory
;    to be used by RAMDRIV.  The first byte is the number of kilo-
;    bytes available for RAMDRIV in that bank.  This value is placed
;    into the BLEN table as the value divided by TRAKLEN.  The actual
;    number of kilobytes of that bank used by RAMDRIV is the integral
;    part of the division.  For instance a 30K bank of memory would
;    be indicated to the system as 30/TRAKLEN.
;
;    The second byte in the BLEN table entry    is the extended (or
;    bank) address byte for that bank of memory.  There is one such
;    entry pair for each bank.  The table is terminated by a single
;    zero byte.
;
;    Thus a system with 20K at a bank addressed as 0DEH and 8K at a
;    bank addressed as 70H could have a BLEN table as:
;
;        BLEN:    DB    20/TRAKLN,0DEH
;            DB    08/TRAKLN,70H
;            DB    0
;
;    while the same system in which the user wanted to reserve 4K on
;    the board at 0DEH for some other purpose could have a BLEN table
;    as:
;
;        BLEN:    DB    16/TRAKLN,0DEH
;            DB    08/TRAKLN,70H
;            DB    0
;
;
;************************************************************************
;
;  The code and tables in this file will reside in high memory, above the
;  existing BIOS.  The system is self-loading.  Typing RAMDRIV3 from the
;  console is sufficient to initiate RAMDRIV3.
;
    .Z80
;
FALSE    EQU    0
TRUE    EQU    NOT FALSE
;
;  The following equates are system dependent.
;
;  DIRBUF:  This is the address of the CP/M directory buffer in the
;    user's BIOS.  CP/M 2.x systems are required to have such a buffer
;    available.  The address will vary in different implementations.
;
;  RAMBUF:  This is the address of the CP/M host buffer in the user's
;    BIOS.  In a normal CP/M 2.x system this buffer will be at least 1K
;    long.  The address will vary in different implementations.
;
;  PANEL:  If you have an (IMSAI-type) front panel, set PANEL=TRUE.  The
;    lights will display the extended address, simulating the LED on the
;    door of the disk drive.  Flipping switch D0 up will "write protect"
;    the RAM drive.
;
;  RAMDRIV:  Set to a memory location above BIOS.  Less than 1K of
;    GLOBAL memory is required at this location; i.e. the same block
;    of memory must be accessible independent of the setting of the ex-
;    tended address bus or any bank byte.
;
;  PRAM:  The extended address of regular program RAM.  Usually this is
;    00H, but need not be.
;
;  XPORT:  The output port that sets the extended address bus or bank
;    byte.
;
;  DNAME:  The alphabetic designation of the RAM drive.
;
;  LIGHTS:  The output port for front panel lights.  This is signif-
;    icant only if PANEL is TRUE.
;
;  SWITCH:  The input port for front panel switches.  This is signif-
;    icant only if PANEL is TRUE.
;
;  TRAKLN:  The number of kilobytes per track.  This must be a minimum
;    of 1K and a maximum no greater than the smallest bank of memory to
;    be made available to RAMDRIV.  A good value to use is the greatest
;    common divisor of each of the memory banks to be used by RAMDRIV.
;
;  DIRECT:  The number of directory entries permitted on the RAM drive.
;    The number specified must be a multiple of 32.  I used 32 to leave
;    the maximum space for program files.
;
    .Z80
;
DIRBUF    EQU    0F77FH        ; CP/M BIOS directory buffer address
RAMBUF    EQU    0F7FFH        ; CP/M BIOS host buffer
PANEL    EQU    FALSE        ;IMSAI FRONT PANEL
RAMDRIV    EQU    0FC00H        ;START OF PROGRAM.
PRAM    EQU    00H        ;EXTENDED ADDR. OF MAIN RAM
XPORT    EQU    0FDH        ;PORT TO SET EXT. ADDR.
DNAME    EQU    'C'        ;DRIVE NAME OF RAMDRIV.
    IF    PANEL
LIGHTS    EQU    0FFH        ;FRONT PANEL LIGHTS.
SWITCH    EQU    0FFH        ;FRONT PANEL SWITCHES.
    ENDIF
TRAKLN    EQU     4        ; kilobytes per track
DIRECT    EQU    32        ;NO. OF DIRECTORY ENTRIES.
;
;  These equates will normally not need to be changed.
;
BDOS    EQU    5
DELCHR    EQU    0E5H        ;DELETED DIRECTORY ENTRY.
DNUMB    EQU    DNAME - 'A'    ;RAMDRIV DRIVE NUMBER
CR    EQU    0DH
LF    EQU    0AH
;
;
;  The code below replaces the original loader code, since that
;  mechanism will not work on a program compiled under M80.  The
;  M80 .PHASE commands have been used rather than the original
;  ORG's.
;
    LD    DE,SIGNON    ; print signon message from loader
    LD    C,9
    CALL    BDOS
;
    LD    HL,(0001)    ; check to see if BIOS modified
    INC    HL        ; point to jump vector
    LD    E,(HL)
    INC    HL
    LD    D,(HL)
    EX    DE,HL
    LD    DE,RAMDRIV
    AND    A        ; clear carry
    SBC    HL,DE        ; WBOOT minus RAMDRIV
    JP    C,CONTIN    ; if carry we are OK
    LD    DE,NOWAY
    LD    C,9
    CALL    BDOS
    JP    0
;
SIGNON:    DB    'RAMDRIV5'
    DB    CR,LF,'$'
NOWAY:    DB    'Cannot load RAMDRIV',CR,LF
    DB    'Cold boot system and try again'
    DB    CR,LF,'$'
;
CONTIN:    LD    HL,SETUP
    LD    DE,RAMDRIV
    LD    BC,1023
    LDIR
    JP    RAMDRIV
;
    .PHASE    RAMDRIV
;
;  ORIGINAL JUMP TABLE FROM BIOS
;
WBOOT1:    DS    48
WCK:                ;END OF BIOS TABLE.
;
CSV:    DS    DIRECT/4    ; this should probably be zero since no
;                    checking is done
ALV:    DS    72        ; this is allocation vector space which
;                    must have 1 bit available per block.
;                    this value corresponds to 576 1K
;                    blocks.
;
;  If the user does not wish to (or cannot) use the directory and host
;  buffers in the system BIOS, the buffers can alternatively be defined
;  here.  In this case the following lines should be uncommented and the
;  corresponding equates above commented.
;
;DIRBUF: DS    128        ; directory buffer
;RAMBUF: DS    128        ; bank communication buffer
;
ENDTBL:                ;END OF DATA TABLES.
;
    .DEPHASE
;
;  The following code is executed once to set up the RAMDRIV system.  In
;  order to conserve space it will be overwritten by data buffers during
;  actual access to RAMDRIV.
;
;
SETUP:
;
    .PHASE    RAMDRIV
;
;  Determine the amount of available RAMDRIV memory
;
    XOR    A
    LD    C,A
    LD    HL,BLEN        ; RAMDRIV memory table
    LD    DE,0002        ; table entry increment
BCHEK0:    LD    A,(HL)        ; get bank kilobytesa
    OR    A        ; zero means end of table
    JR    Z,BCHEK1
    ADD    A,C        ; accumulate count
    LD    C,A        ; and save it
    ADD    HL,DE        ; point to next BLEN entry
    JR    BCHEK0
;
BCHEK1:    CP    C        ; is there any ram available at all?
    JR    NZ,RAMOK    ; jump if there is
    LD    DE,NORAM    ; no ram, tell the user
    LD    C,9
    CALL    BDOS
    RET            ; avoid warm boots!
;
NORAM:    DB    'Cannot activate RAMDRIV.  No available RAM.'
    DB    CR,LF,'$'
;
RAMOK:    XOR    A        ; clear counter
    LD    B,TRAKLN    ; the count must be multiplied
;                    by TRAKLN to yeild kilobytes
RAMOK1:    ADD    A,C        ; multiply by repeated adding
    DJNZ    RAMOK1
;
    DEC    A        ; RAMDRIV kilobytes minus 1
    LD    (DSM),A        ; maximum block number to DPB
;
;  MODIFY BIOS JUMP TABLES
;
    IF    $ LT WCK    ;MAKE SURE THAT WBOOT1 TABLE
    JP    BJUMP        ;WILL NOT OVERWRITE
    ENDIF            ;BJUMP ROUTINE.
    IF    $ LT WCK
    DEFS    WCK - $
    ENDIF
;
BJUMP:    LD    HL,(1)        ;GET ADDRESS OF WARM BOOT
    LD    DE,WBOOT1    ;TRANSFER TABLE FROM BIOS UP HERE
    LD    BC,48        ;48 BYTES
    LDIR
    LD    HL,WBOOT2    ;TRANSFER OUR TABLE TO BIOS
    LD    DE,(0001)
    LD    BC,48
    LDIR
;
;  PRINT MESSAGE AND ASK QUESTION
;
    LD    DE,QUEST
    LD    C,9        ;PRINT STRING
    CALL    BDOS
    LD    C,1        ;GET CHARACTER
    CALL    BDOS
    RES    5,A        ;CONVERT TO UPPER CASE.
    CP    'Y'
    JP    NZ,QUIT
;
;  CLEAR DIRECTORY OF RAMDRIV
;
    LD    BC,0000        ; directory on track 0 sector 0
    CALL    MAP
    OUT    (XPORT),A
    IF    PANEL
    CPL
    OUT    (LIGHTS),A    ;TO IMSAI FRONT PANEL
    ENDIF
    EX    DE,HL        ; HL = base location of directory
    LD    DE,32        ;EVERY 32 BYTES
    LD    B,DIRECT    ;NO. OF ENTRIES.
    LD    A,DELCHR
CLEAR:    LD    (HL),A
    ADD    HL,DE
    DJNZ    CLEAR
    LD    A,PRAM        ;RESET EXT. ADDR.
    OUT    (XPORT),A
    IF    PANEL
    CPL
    OUT    (LIGHTS),A
    ENDIF
;
QUIT:    LD    DE,CRLF
    LD    C,9
    CALL    BDOS
    JP    0        ;BACK TO CP/M.
;
QUEST:    DB    CR,LF
    DB    'RAMDRIV active on drive ',DNAME
    DB    CR,LF
    DB    'Should directory of drive ',DNAME
    DB    ' be cleared (Y/N)? $'
CRLF:    DB    CR,LF,'$'
;
;  NEW TABLE COPIED INTO BIOS
;
WBOOT2:    JP    WBOOT
    JP    WBOOT1+3
    JP    WBOOT1+6
    JP    WBOOT1+9
    JP    WBOOT1+12
    JP    WBOOT1+15
    JP    WBOOT1+18
    JP    HOME        ;21
    JP    SELDSK        ;24
    JP    SETTRK        ;27
    JP    SETSEC        ;30
    JP    SETDMA        ;33
    JP    READ        ;36
    JP    WRITE        ;39
    JP    WBOOT1+42
    JP    SECTRN        ;45
;
;  IMPLEMENT BIOS FUNCTIONS
;
    IF    $ LT ENDTBL    ;MAKE SURE THAT BIOS
    DEFS    ENDTBL - $    ; FUNCTIONS BEGIN
    ENDIF            ; AFTER TABLES.
;
WBOOT:    LD    HL,80H        ;SET INITIAL DMA ADDR.
    LD    (DMAADR),HL
    JP    WBOOT1        ;BACK TO BIOS
;
;
HOME:    LD    A,(DISK)    ;CHECK DISK NUMBER.
    CP    DNUMB        ;IS IT THE RAMDRIV?
    JP    NZ,WBOOT1+21    ;IF NOT, LET BIOS HANDLE IT.
    LD    A,0        ;SET "TRACK" TO 0
    LD    (XTRAK),A
    RET
;
;
SELDSK:    LD    A,C        ;CHECK REQUESTED DISK,
    LD    (DISK),A
    CP    DNUMB
    JP    NZ,WBOOT1+24
    LD    HL,DPH        ;RETURN DISK PAR. HEADER.
    RET
;
;  DISK PARAMETER HEADER FOR RAMDRIV
;
DPH:
    DW    0        ;NO SECTOR TRANSLATION
    DW    0,0,0        ;SCRATCH
    DW    DIRBUF        ;LOC. OF SCRATCHPAD AREA.
    DW    DPB        ;DISK PARAMETER BLOCK
    DW    CSV        ;DIR. CHECK AREA
    DW    ALV        ;ALLOC. VECTOR.
;
;  DISK PARAMETER BLOCK
;
DPB:
    DW    (1024*TRAKLN)/128    ;SECTORS PER TRACK
    DB    3        ;BSH
    DB    7        ;BLM
    DB    0        ;EXM
DSM:    DW    62        ;MAX BLOCK NO.
    DW    DIRECT-1    ;HIGHEST DIRECT. NO.
;
AL0    EQU    LOW (0FFH SHL (8-DIRECT/32))
AL1    EQU    0
;
    DB    AL0,AL1        ;DIRECTORY BLOCKS.
;
CKS    EQU    0        ;CHECK DIRECT. ENTRIES.
;
    DW    CKS
    DW    0        ;NO SKIPPED TRACKS.
;
;
SETTRK:    LD    A,(DISK)
    CP    DNUMB
    JP    NZ,WBOOT1+27
    LD    A,C        ;TRACK NO.
    LD    (XTRAK),A
    RET
;
;
SETSEC:    LD    A,(DISK)
    CP    DNUMB
    JP    NZ,WBOOT1+30
    LD    (SECTOR),BC
    RET
;
;
SETDMA:    LD    (DMAADR),BC    ;SAVE DMA ADDR. BOTH HERE
    JP    WBOOT1+33    ;AND IN BIOS.
;
;
READ:    LD    A,(DISK)
    CP    DNUMB
    JP    NZ,WBOOT1+36
    LD    BC,(SECTOR)    ; but we asssume sector fits in one byte
    LD    A,(XTRAK)    ;SET EXTENDED ADDRESS.
    LD    B,A
    CALL    MAP        ; to compute bank and offset
    OUT    (XPORT),A
    IF    PANEL
    CPL
    OUT    (LIGHTS),A
    ENDIF
    EX    DE,HL
    LD    DE,RAMBUF    ;TEMPORARY BUFFER.
    LD    BC,128        ;SECTOR=128 BYTES.
    LDIR
    LD    A,PRAM        ;RESET ADDR.
    OUT    (XPORT),A
    IF    PANEL
    CPL
    OUT    (LIGHTS),A
    ENDIF
    LD    HL,RAMBUF    ;MOVE FROM BUFFER
    LD    DE,(DMAADR)    ; back to main ram
    LD    BC,128
    LDIR
    XOR    A        ; show no errors
    RET
;
;
WRITE:    LD    A,(DISK)
    CP    DNUMB
    JP    NZ,WBOOT1+39
    IF    PANEL
    IN    A,(SWITCH)    ;CHECK D0 OF FRONT PANEL
    AND    1
    RET    NZ        ;RETURN IF WRITE PROTECT.
    ENDIF
    LD    HL,(DMAADR)    ;DMA --> BUFFER
    LD    DE,RAMBUF
    LD    BC,128
    LDIR
;
    LD    BC,(SECTOR)    ; but we assume sector < 256
    LD    A,(XTRAK)
    LD    B,A
    CALL    MAP
    OUT    (XPORT),A
    IF    PANEL
    CPL
    OUT    (LIGHTS),A
    ENDIF
    LD    HL,RAMBUF    ;BUFFER --> RAMDRIV.
    LD    BC,128
    LDIR
;
    LD    A,PRAM
    OUT    (XPORT),A
    IF    PANEL
    CPL
    OUT    (LIGHTS),A
    ENDIF
    XOR    A        ; show no error
    RET
;
;
SECTRN:    LD    A,(DISK)
    CP    DNUMB
    JP    NZ,WBOOT1+45
    LD    H,B
    LD    L,C
    RET
;
;
;  Subroutine to calculate RAM address and bank
;
;    called with  B = track number (starts from 0)
;             C = sector number (starts from 0)
;
;    returns with A = extended address byte
;            DE = offset into bank for start of sector
;
MAP:    XOR    A        ; clear A
    LD    A,B        ; track number to A
    LD    DE,2        ; increment for BLEN table
    LD    HL,BLEN
;
MAP1:    SUB    (HL)        ; subtract bank length in K's
    JR    C,MAP2        ; jump if track in this bank
    ADD    HL,DE        ; point to next BLEN entry
    JR    MAP1        ; repeat till done
;
MAP2:    ADD    A,(HL)        ; A = relative track number in bank
    RLCA            ; multiply by 4K
    RLCA
    RLCA
    RLCA
    LD    E,D        ; clear E
    LD    D,C        ; multiply sector number by 128
    RR    D
    RR    E
    ADD    A,D        ; add to track starting address
    LD    D,A        ; DE = sector start in bank
    INC    HL
    LD    A,(HL)        ; A = extended (bank) address
    RET
;
BLEN:    DB    32/TRAKLN,0FFH    ; first bank has 32K at FF
    DB    32/TRAKLN,0FEH    ; second bank has 32K at FE
    DB    04/TRAKLN,001H    ; third bank has 4K at 01
    DB    0        ; end of table
;
;  DATA STORAGE AREA
;
DISK:    DB    0
XTRAK:    DB    0
DMAADR:    DW    80H
SECTOR:    DW    0
;
    .DEPHASE
;
    END