Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-01/gospeed.zip/SPEED.ASM

Assembly Source File | 1990-05-28 | 11KB | 327 lines

    page    58,132
    TITLE    Go -- Control (and measure) speed for Heath/Zenith PC

;    (c) Copyright 1987 David E. Tweten

;    All rights reserved.  Permission for distribution is granted
;    provided that no direct commercial advantage is gained, and
;    provided that this copyright notice appears on all copies.

;    --------------------------------------------------------------------
;
;    Go serves three purposes relating to Dante Bencivengo's "TurboPlus
;    V2.0" modification to 4.77 MHz Heath/Zenith PCs.  It permits FORMAT
;    and VERIFY ON to work.  It also permits the user to speed or slow
;    the processor.  Finally, it measures the processor's speed setting
;    (primarily for batch file use).  "TurboPlus", the predecessor
;    version of "TurboPlus V2.0", was described in the June, 1986 issue
;    of REMark, the journal of the Heath/Zenith Users' Group.
;
;    Due to a quirk in the diskette BIOS, errors will occur when a track
;    format or verify operation is requested at any high speed, or when
;    any diskette operation is attempted at 8 MHz.  The terminate-and-
;    stay-resident portion of this code will prevent the errors from
;    occuring by slowing the processor for the duration of the
;    operation, unless it is already operating at the slow (4.77 MHz)
;    speed.
;
;    The optional switch for Go can specify the speed to use when not
;    formatting or verifying a floppy disk.  It can be "f", which will
;    set the clock speed to fast, or it can be "s", which will set the
;    clock speed to slow.  In any but its initial (TSR installing) call,
;    if no switch is given, Go does not change the speed setting.  On
;    the initial call, if no argument is given, Go assumes "f".  Go uses
;    whatever switch character is current.
;
;    The termination code for Go is set according to the processor speed
;    at call, and by whether or not it has previously been called.  The
;    meaning of its termination code is as follows:
;
;         0 - Go has been called before so the TSR portion is already
;             resident.  Before the call the clock was set to run at
;             4.77 MHz.
;
;         1 - Go has been called before so the TSR portion is already
;             resident.  Before the call the clock was set to run at
;             its fast speed.
;
;         2 - Go has not been called before.  This call installed the TSR
;             code and set the clock speed to the specified value (either
;             Fast or Slow).  If no speed was specified on the call, the
;             default of Fast was used.
;
;         3 - Go has been called in error.  It did nothing.
;
;    NOTE that the actual processor speed is the slower of the speed
;    specified and detected by Go, and the speed specified by the
;    hardware switch included in the "TurboPlus V2.0".  The actual speed
;    is indicated by the LED included with the "TurboPlus V2.0" package.
;
;    Written by:  David E. Tweten   <[e-mail]>
;
;                                   12141 Atrium Drive
;                                   Saratoga, CA  95070
;
;                                   [phone]
;
;    Inspiration: FV.COM, a program of unstated authorship, included on
;                 the "TurboPlus" software disk.
;
;    Modification History:
;
;       1.0      5-10-87  Initial version.
;
;    --------------------------------------------------------------------

IGROUP    group    _TEXT

BLK_HDR_SEGMENT segment at 00000H
blk_flag db    ?            ; 'M' for normal, 'Z' for final block
blk_owner dw    ?            ; segment of owner's PSP
blk_psize dw    ?            ; block size in paragraphs
BLK_HDR_SEGMENT ends

STDOUT    equ    1            ; File handle for Standard Output
STDERR    equ    2            ; File handle for Standard Error
CR    equ    0DH            ; ASCII code for Carriage Return
LF    equ    0AH            ; ASCII code for Line Feed
HT    equ    09H            ; ASCII code for Horizontal Tab
LEDS    equ    0C0H            ; Port address of "CPU LEDs"
SLOW    equ    1FH            ; Turn off all LEDs but "RDY"
FAST    equ    3FH            ; Turn off all LEDs
VERIFY    equ    4            ; Diskette sector verify service number
FORMAT    equ    5            ; Format diskette track service number

    SUBTTL    Resident Interrupt Filter
    page
_TEXT    segment    para public 'CODE'
    assume    cs:_TEXT,ds:NOTHING,es:NOTHING,ss:NOTHING

    org    02CH
env_seg    dw    ?            ; Seg addr for our copy of environment

    org    05CH
beg_ovr:                 ; Beginning of overwritten PSP area

    org    080H
istrlen    db    ?            ; Invocation string and length
istring    equ    $

    org    100h
START:    jmp    go            ; Jump around the resident portion.

    org    10CH            ; Offset in paragraph same as beg_ovr
beg_pr:                    ; Beginning of part to move into PSP

res_offs equ    (beg_pr-beg_ovr) SHR 4    ; Paragraphs to move resident

rom_dsk dd    ?            ; ROM INT 13 service routine address
speed    db    FAST            ; "Normal" speed, set by command switch

int_13    proc    far
    pushf                ; IF and TF were cleared by the INT 13.
    cmp    dl,80h            ; If it's a Winchester operation,
    jae    short call_rom        ;  just go do it.
;
; The following code block is for TurboPlus V2.0 installations running at
; speeds below 8.0 MHz.  At 8.0 MHz, all floppy disk operations must be
; performed at low speed.  Below 8.0 MHz, only "verify sector" and "format
; track" need to be run at low speed.
;
    ifndef    MHZ8
    cmp    ah,VERIFY        ; If it's not a verify operation,
    je    short go_slow
    cmp    ah,FORMAT        ;  and it's not a format operation,
    jne    short call_rom        ;  just do it.
go_slow:
    endif
;
; The previous code block is for TurboPlus V2.0 installations running at
; speeds below 8.0 MHz.
;
    popf                ; Recover flags at entry, and leave
    pushf                ;  them at stack top for simulated INT.
    push    ax
    mov    al,SLOW
    out    LEDS,al            ; Slow to 4.77 MHz.
    pop    ax
    call    rom_dsk            ; Simulate INT 13 with return here.
    push    ax
    mov    al,speed
    out    LEDS,al            ; Resume speed(ing).
    pushf                ; Put flags where we can get them.
    push    bp
    mov    bp,sp
    mov    ax,[bp+10]        ; Extract IF and TF from user's flags,
    and    ax,300H
    or    ax,[bp+2]        ;  merge them with returned flags,
    mov    [bp+10],ax        ;  and put them back for the IRET.
    pop    bp            ; Restore the registers,
    add    sp,+2            ;  ignoring the flags.
    pop    ax
    iret                ; Return to caller with proper flags.

call_rom:
    popf                ; Recover flags at entry.
    jmp    rom_dsk            ; Simulate interrupt entry into ROM.
int_13    endp

res_bl    equ    $-beg_pr        ; Length of resident
cod_bl    equ    $-int_13        ; Length of resident code

    SUBTTL    Non-resident Code
     page
    assume    ds:_TEXT,es:_TEXT,ss:_TEXT
;
; Non-resident data
;
copyright db    "(c) Copyright 1987 David E. Tweten.  All rights reserved."
version    db    "Go version 1.0 installed, for use "
    ifdef    MHZ8
    db    "at"
    else
    db    "below"
    endif
    db    " 8.0 MHz.", CR, LF
VERSION_L equ    $-version
mes_env    db    "Warning: can't return environment copy memory.", CR, LF
MES_ENV_L equ    $-mes_env
mes_err    db    "Error: switch value unrecognized.", CR, LF
MES_ERR_L equ    $-mes_err
mes_use    db    "Usage: go [ "
swchar    db    "*"
    db    "fs ]", CR, LF
MES_USE_L equ    $-mes_use

    even

sibling    dw    ?            ; Effective PSP segment addr of twin

go:
    cld
    mov    ax,3700H        ; Get switch character
    int    21H            ;  (UNDOCUMENTED MS-DOS FUNCTION).
    mov    swchar,dl
    mov    ah,52H            ; Get seg. addr. of first memory block
    int    21H            ;  (UNDOCUMENTED MS-DOS FUNCTION).
    mov    dx,es:[bx-2]
    mov    sibling,ds        ; Initialize PSP seg. addr. to our own.
blkscn:
    assume    es:BLK_HDR_SEGMENT    ; See if we're already installed.
    mov    es,dx
    cmp    blk_flag,'Z'        ; If we've checked the last block,
    je    short first        ;  end this nonsense.
    inc    dx            ; Compute segment address of next
    add    dx,blk_psize        ;  block.
    mov    ax,blk_owner        ; Get block owner's PSP segment addr.
    sub    ax,res_offs        ; Modify it to account for our resident
    mov    es,ax            ;  code shift.
    mov    si,offset int_13    ; Get offset for the resident code.
    mov    di,si
    mov    cx,cod_bl        ; Get resident code byte count.
    repe    cmpsb            ; OK, we've seen the enemy; is he us?
    jne    blkscn            ; If he ain't, keep looking.
    mov    sibling,es        ; Save segment address of our twin.
    mov    ah,es:speed        ; Set our default to our twin's.
first:
    assume    es:_TEXT
    mov    dx,ds
    mov    es,dx
    mov    si,offset istring    ; Initialize argument string pointer
    mov    cl,istrlen        ;  and count.
    xor    ch,ch
whitesp:
    jcxz    short default        ; Skip over leading white space in
    lodsb                ;  argument string.
    dec    cx
    cmp    al,' '
    je    whitesp
    cmp    al,HT
    je    whitesp
    cmp    al,swchar        ; If first non-blank is not the switch
    jne    short badarg        ;  character, return error.
    mov    al,[si]            ; Get the switch value.
    or    al,20H            ; Force it to lowercase.
    mov    ah,FAST            ; If the switch is "/f", it's fast.
    cmp    al,'f'
    je    short found
    mov    ah,SLOW            ; If the switch is "/s", it's slow.
    cmp    al,'s'
    je    short found
badarg:
    mov    ah,40H            ; If none of the above, it's an error;
    mov    dx,offset mes_err    ;  complain bitterly.
    mov    cx,MES_ERR_L
    mov    bx,STDERR
    int    21H
error:
    mov    ah,40H            ; Display usage message.
    mov    dx,offset mes_use
    mov    cx,MES_USE_L
    mov    bx,STDERR
    int    21H
    mov    al,3            ; Set return error status.
exit:
    mov    ah,4ch            ; Exit with status.
    int    21H

found:
    mov    al,ah            ; Change to the new speed.
    out    LEDS,al
    mov    es,sibling        ; Note the new default speed.
    xchg    es:speed,ah
    mov    dx,ds
    mov    es,dx
default:
    cmp    dx,sibling
    je    short grabint
    mov    al,0
    cmp    ah,SLOW
    je    exit
    mov    al,1
    jmp    exit

grabint:
    mov    ax,3513H        ; Get address of diskette (13H)
    int    21H            ;  interrupt response routine.
    mov    (word ptr rom_dsk)[word * 0],bx ; Move ES:BX to rom_dsk.
    mov    (word ptr rom_dsk)[word * 1],es
    mov    ax,cs            ; Relocate our resident portion.
    mov    es,ax
    mov    si,offset beg_pr
    mov    di,offset beg_ovr
    mov    cx,res_bl
    rep    movsb
    mov    ax,cs            ; Now set new value in the interrupt
    sub    ax,res_offs        ;  vector for 13H
    mov    ds,ax
    mov    dx,offset int_13
    mov    ax,2513H        ;  as int_13.
    int    21H
    mov    ax,cs            ; Restore data segment register.
    mov    ds,ax
    mov    ah,40H
    mov    dx,offset version
    mov    cx,VERSION_L
    mov    bx,STDOUT
    int    21H            ; Display the version number.
    mov    es,env_seg        ; Return space for copy of environment.
    mov    ah,49H
    int    21H
    jnc    short tsr        ; If we can't give back the environment
    mov    ah,40H            ;  copy, complain (but not bitterly).
    mov    dx,offset mes_env
    mov    cx,MES_ENV_L
    mov    bx,STDERR
    int    21H
tsr:
    mov    dx,di            ; Terminate and stay resident.
    add    dx,15
    mov    cl,4
    shr    dx,cl
    mov    ax,3102H        ; Compute size of resident portion in
    int    21H            ;  paragraphs, and leave it behind.

_TEXT    ends
    end    START