Black Box 4/BlackBox.cdr/progc/djsrc106.arj/TRIDNT89.ASM

Assembly Source File | 1992-04-08 | 4KB | 229 lines

; This is file TRIDNT89.ASM
;
; Copyright (C) 1991 DJ Delorie, 24 Kirsten Ave, Rochester NH 03867-2954
;
; This file is distributed under the terms listed in the document
; "copying.dj", available from DJ Delorie at the address above.
; A copy of "copying.dj" should accompany this file; if not, a copy
; should be available from where this file was obtained.  This file
; may not be distributed without a verbatim copy of "copying.dj".
;
; This file is distributed WITHOUT ANY WARRANTY; without even the implied
; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
;

cseg    segment    byte public 'code'
    assume    cs:cseg, ds:cseg, es:cseg, ss:nothing

    dw    offset init_routine
    dw    offset paging_routine
    dw    0    ; set to 1 if separate read & write windows or
            ; only 64K of video RAM (ie: no paging)

def_tw    dw    80    ; filled in by go32 if GO32 env. var. is set
def_th    dw    25
def_gw    dw    640
def_gh    dw    480

;--------------------------------------------------------------------------
; Entry: AX=mode selection
;        0=80x25 text
;        1=default text
;        2=text CX cols by DX rows
;        3=biggest text
;        4=320x200 graphics
;        5=default graphics
;        6=graphics CX width by DX height
;        7=biggest non-interlaced graphics
;        8=biggest graphics
;
; NOTE: This runs in real mode, but don't mess with the segment registers.
;
; Exit:  CX=width (in pixels or characters)
;        DX=height

init_table    label    word
    dw    offset init_0
    dw    offset init_1
    dw    offset init_2
    dw    offset init_3
    dw    offset init_4
    dw    offset init_5
    dw    offset init_6
    dw    offset init_7
    dw    offset init_8

init_routine    proc    far
    cmp    ax,8
    jbe    valid_req
    ret
valid_req:
    shl    ax,1
    mov    bx,ax
    jmp    init_table[bx]

init_0: ; 80x25 text
    mov    ax,3
    int    10h
    mov    cx,80
    mov    dx,25
    ret

init_1: ; default text
    mov    cx,def_tw
    mov    dx,def_th
    jmp    init_2

init_2_table    label    word
    dw    01h, 40, 25
    dw    03h, 80, 25
init_2_tend    label    word

init_2: ; CX*DX text
    mov    si,offset init_2_table
init_2a:
    cmp    [si+2],cx
    jb    init_2b
    cmp    [si+4],dx
    jb    init_2b
    ; got a big enough one!
    jmp    init_2c
init_2b:
    cmp    si,offset init_2_tend - 6
    je    init_2c
    add    si,6
    jmp    init_2a
init_2c:
    mov    ax,[si]
    push    si
    int    10h
    pop    si
    mov    cx,[si+2]
    mov    dx,[si+4]
    ret

init_3: ; biggest text
    mov    ax,[init_2_tend-6]
    int    10h
    mov    cx,[init_2_tend-4]
    mov    dx,[init_2_tend-2]
    ret

init_4: ; 320x200 graphics
    mov    ax,13h
    int    10h
    mov    cx,320
    mov    dx,200
    ret

init_5: ; default graphics - should be 640x480 if supported
    mov    cx,def_gw
    mov    dx,def_gh
    jmp    init_6

init_6_table    label    word
    dw    13h, 320, 200
    dw    5ch, 640, 400
    dw    5dh, 640, 480
    dw    5eh, 800, 600
    dw    62h, 1024, 768
init_6_tend    label    word

init_6: ; CX*DX graphics
    mov    si,offset init_6_table
init_6a:
    cmp    [si+2],cx
    jb    init_6b
    cmp    [si+4],dx
    jb    init_6b
    ; got a big enough one!
    jmp    init_6c
init_6b:
    cmp    si,offset init_6_tend - 6
    je    init_6c
    add    si,6
    jmp    init_6a
init_6c:
    mov    ax,[si]
    push    si
    int    10h
    pop    si
    mov    cx,[si+2]
    mov    dx,[si+4]
    ret

init_7: ; biggest non-interlaced graphics
    mov    ax,5eh
    int    10h
    mov    cx,800
    mov    dx,600
    ret

init_8: ; biggest graphics
    mov    ax,62h
    int    10h
    mov    cx,1024
    mov    dx,768
    ret

init_routine    endp

;--------------------------------------------------------------------------
; Entry: AH=read page
;        AL=write page
;
; NOTE: This runs in protected mode!  Don't mess with the segment registers!
; This code must be relocatable and may not reference any data!
;
; Exit: VGA configured.
;       AX,BX,CX,DX,SI,DI may be trashed
;
; Code derived from VGAKIT version 3.4
;    Copyright 1988,89,90 John Bridges

    assume    ds:nothing, es:nothing

paging_routine    proc    far
    mov    cx,ax
    mov    dx,3ceh        ;set page size to 64k
    mov    al,6
    out    dx,al
    inc    dl
    in    al,dx
    dec    dl
    or    al,4
    mov    ah,al
    mov    al,6
    out    dx,al
    inc    dx
    xchg    ah,al
    out    dx,al
    dec    dx

    mov    dl,0c4h        ;switch to BPS mode
    mov    ax,000bh
    out    dx,al
    inc    dx
    xchg    ah,al
    out    dx,al
    dec    dx
    in    al,dx

    mov    ah,cl
    xor    ah,2
    mov    dx,3c4h
    mov    al,0eh
    out    dx,al
    inc    dx
    xchg    ah,al
    out    dx,al
    dec    dx

    ret
paging_routine    endp

;--------------------------------------------------------------------------

cseg    ends
    end