The Atari Compendium/The Atari Compendium (Toad Computers) (1994).iso/files/umich/telecomm/sticpsrc.lzh/SOURCE.ARC/PCGEN.ASM

Assembly Source File | 1990-08-01 | 4.2 KB | 244 lines

    NAME pcgen
    include    pmacros.h

dseg
pubvar    mtasker,<db ?>
dsegend

if TURBO
else
; setvect - set interrupt vector
; called from C as follows
; setvect(vec,vecval)
; char vec;        /* Interrupt number */
; void (*vecval)();    /* offset (and segment in large code model) */

    procdef    setvect,<<vec,byte>,<ipval,fptr>>
    mov    ah,25h
    mov    al,vec
    push    ds        ; save
ifdef    LARGECODE
    lds    dx,ipval
else
    mov    dx,ipval
    push    cs
    pop    ds
endif
    int    21h
    pop    ds        ; restore
    pret
    pend    setvect

; getvect - return current interrupt vector
; called from C as
; long        /* Returns CS in high word, IP in low word */
; getvect(vecnum)
; char vecnum;    /* Interrupt number */

    procdef    getvect,<<vecnum,byte>>
    mov    ah,35h
    mov    al,vecnum
    push    es    ; save, since DOS uses it for a return value
    int    21h
    mov    dx,es    ; CS value into DX (C high word)
    mov    ax,bx    ; IP value into AX (C low word)
    pop    es    ; restore es
    pret
    pend    getvect
endif

; kbraw - raw, nonblocking read from console
; If character is ready, return it; if not, return -1

    procdef kbraw
    mov    ah,06h    ; Direct Console I/O
    mov    dl,0ffh ; Read from keyboard
    int    21h    ; Call DOS
    jz    nochar    ; zero flag set -> no character ready
    mov    ah,0    ; valid char is 0-255
    pret
nochar:
    mov    ax,-1    ; no char, return -1
    pret
    pend    kbraw

; disable - disable interrupts and return previous state: 0 = disabled,
;           1 = enabled

 if    TURBO
    procdef    Disable
 else
    procdef    disable
 endif
    pushf            ; save state on stack
    cli            ; interrupts off
    pop    ax        ; original flags -> ax
    and    ax,200h        ; 1<<9 is IF bit
    jnz    ion        ; nonzero -> interrupts were on
    pret
ion:    mov    ax,1
    pret
 if    TURBO
    pend    Disable
 else
    pend    disable
 endif

; restore - restore interrupt state: 0 = off, nonzero = on

    procdef    restore,<<istate,byte>>
    test    istate,0ffh
    jz    ioff
    sti
ioff:    pret
    pend    restore

; Halt until an interrupt occurs, then return
    procdef eihalt
    sti    ; make sure interrupts are enabled
    hlt
    pret
    pend    eihalt

; multitasker types
NONE        equ    0
DOUBLEDOS    equ    1
DESQVIEW    equ    2

; Relinquish processor so other task can run
    procdef    giveup
    cmp    mtasker@,DOUBLEDOS
    jnz    givedesqview
    mov    al,2        ; 110 ms
    mov    ah,0eeh
    int    21h

givedesqview:
    cmp    mtasker@,DESQVIEW
    jnz    notask
    mov    ax,1000h
    int    15h
notask:
    pret
    pend    giveup

; check for a multitasker running
    procdef chktasker
    mov    mtasker@,NONE
    ; do the doubledos test
    mov    ah,0e4h
    int    21h
    cmp    al,1
    jz    isdos
    cmp    al,2
    jnz    test_desq
isdos:    mov    mtasker@,DOUBLEDOS
    pret

    ; test for desqview
test_desq:
    mov    ax,2b01h
    mov    cx,4445h
    mov    dx,5351h
    int    21h
    cmp    al,0ffh
    jnz    isdesq
    pret
isdesq:    mov    mtasker@,DESQVIEW
    pret
    pend    chktasker

; getds - Read DS for debugging purposes
    procdef    getds
    getds
    pret
    pend    getds
;
; dos service routine used by JK1NNT installed by N3EUA
;

    procdef    jkintdos,<<reg_a,word>,<reg_b,word>,<reg_d,word>>
    mov    ax,reg_a
    mov    bx,reg_b
    mov    dx,reg_d
    int    21h
    pret
    pend    jkintdos
;
; NEC PC-9801 speed setting routine by JK1NNT installed by N3EUA
;
    procdef    set_speed,<<s_code,word>>
    push    ds
    mov    ax,40h
    mov    ds,ax
    mov    dx,s_code
    mov    ds:[269h],dl
    mov    dh,4ch
    mov    ds:[268h],dh
    pop    ds
    mov    cl,0ah
    int    0dch
    pret
    pend    set_speed

;
; This routine is a generic int 21h handler, is used only by disk free
; routine.  Added by K3MC  3 Dec 87
;
;
; General-purpose int 21h caller, currently used only to return AX, BX, CX, DX
; for computing amount of free disk space, and amount of total disk space.
;
; declared as: void isfree();
;
; Called from C as:
;
; isfree(&ax,&bx,&cx,&dx)
; unsigned short ax,bx,cx,dx;
;
    procdef    isfree,<<c_ax,ptr>,<c_bx,ptr>,<c_cx,ptr>,<c_dx,ptr>>
    push    ax
    push    bx
    push    cx
    push    dx
    push    bp
    push    si
    push    di
    pushds
    ldptr    di,c_ax,ds
    mov    ax,[di]
    ldptr    di,c_bx,ds
    mov    bx,[di]
    ldptr    di,c_cx,ds
    mov    cx,[di]
    ldptr    di,c_dx,ds
    mov    dx,[di]
    int     21h
    ldptr    di,c_ax,ds
    mov    [di],ax
    ldptr    di,c_bx,ds
    mov    [di],bx
    ldptr    di,c_cx,ds
    mov    [di],cx
    ldptr    di,c_dx,ds
    mov    [di],dx
    popds
    pop    di
    pop    si
    pop    bp
    pop    dx
    pop    cx
    pop    bx
    pop    ax
    pret
    pend    isfree

; Return 03 in AL to fail a critical error

    pubproc    crit_hdl
    mov    al,3
    iret
    pend    crit_hdl

    end