BBS 1/BBS#1.iso/grafika/video.ha/EGA64.ASM

Assembly Source File | 1993-04-28 | 3KB | 214 lines

;    EGA-64.asm
;    Displays 64 colors on EGA display in text mode!!!
;
;    Written by Alex Yakovlev. ([e-mail])
;

    Ideal
    Model    Tiny
    CodeSeg

    Org    100h

Start:
    Mov    ah,12h
    Mov    bl,10h
    Int    10h
    Cmp    bl,10h
    Jne    @@Ok

    Mov    ah,9
    Mov    dx,OffSet NoEGA
    Int    21h

    Ret

NoEGA    Db    'Sorry, EGA needed.', 13,10, '$'

@@Ok:
;                Draw a picture
    Mov    ax,0B800h
    Mov    es,ax
    Xor    di,di

    Cld
    Mov    cx,23
Lp1:    Push    cx
    Mov    al,'█'
    Mov    ah,08h
Lp2:
    Mov    cx,10
    Rep    StoSw
    Inc    ah
    Cmp    ah,10h
    Jb    Lp2

    Pop    cx
    Loop    Lp1

    Mov    si,OffSet Msg
    Mov    ah,07h
Lf1:
    LodSb
    Or    al,al
    Jz    Lf2
    StoSw
    Jmp    Lf1
Lf2:

;                Show all colors
    Cli

    Xor    ax,ax
    Mov    ds,ax
;                Store old Int09 vector
    Mov    ax,[ds: 4*9+0]
    Mov    [cs:OldOfs],ax
    Mov    ax,[ds: 4*9+2]
    Mov    [cs:OldSeg],ax
;                Set my Int09
    Mov    [ds: 4*9+2],cs
    Mov    ax,OffSet Int09
    Mov    [ds: 4*9+0],ax
;                Mask all IRQs except Keyboard
    Mov    al,11111101b
    Out    21h,al

    Sti
    Jmp    Loc3

Msg    Db    "A Great program, isn't it ?...            "
    Db    "Copyright (c) by Alex Yakovlev.       ", 0

Loc1:
;                Wait for retrace
Lc7:    In    al,dx
    Test    al,1
    Jz    Lc7
;                Set palette register
    Mov    bl,8
Ll1:    Mov    dx,3C0h
    Mov    al,bl
    Out    dx,al
    Mov    al,bh
    Out    dx,al
;                Increase color number
    Inc    bl
    Inc    bh
    Cmp    bl,16
    Jb    Ll1
;                Skip line
    Mov    dx,3DAh
Lc4:    In    al,dx
    Test    al,1
    Jnz    Lc4
;                Wait for retrace end
Lc5:    In    al,dx
    Test    al,1
    Jz    Lc5
;                If all colors are already displayed
    Cmp    bh,64
    Ja    Loc3
;                Enable display
    Mov    dx,3C0h
    Mov    al,20h
    Out    dx,al

    Mov    ah,38            ; ... Lines per color
    Mov    dx,3DAh

Lc1:    In    al,dx
    Test    al,1
    Jnz    Lc1            ; Wait for retrace end

    Dec    ah
    Jz    Loc1

Lc2:    In    al,dx
    Test    al,1
    Jz    Lc2            ; Wait for retrace

    Jmp    Lc1

Loc3:
;                Blank palette
    Mov    bl,8
    Mov    dx,3C0h
Ll3:
    Mov    al,bl
    Out    dx,al
    Mov    al,0
    Out    dx,al
    Inc    bl
    Cmp    bl,16
    Jb    Ll3
;                Enable display
    Mov    dx,3C0h
    Mov    al,20h
    Out    dx,al
;                Wait for vert retrace
    Mov    dx,3DAh
Lc3:    In    al,dx
    Test    al,1000b
    Jz    Lc3

    Mov    bh,0
    Jmp    Loc1

Int09:
    Add    sp,6
;                Restore old Int09 vector
    Mov    ax,[cs:OldOfs]
    Mov    [ds: 4*9+0],ax
    Mov    ax,[cs:OldSeg]
    Mov    [ds: 4*9+2],ax

    Push    cs
    Pop    ds
;                Initialize 3C0 port
    Mov    dx,3DAh
    In    al,dx
;                Set standard palette
    Mov    bl,8
    Mov    dx,3C0h
Ll4:
    Mov    al,bl
    Out    dx,al
    Mov    al,bl
    Add    al,38h-8
    Out    dx,al
    Inc    bl
    Cmp    bl,16
    Jb    Ll4
;                Enable display
    Mov    al,20h
    Out    dx,al
;                Enable all IRQs
    Mov    al,0
    Out    21h,al
    Sti
;                Call Old Int09 handler
    Int    09
;                Cls
    Mov    ax,0B800h
    Mov    es,ax
    Mov    ax,0720h
    Xor    di,di
    Mov    cx,2000
    Rep Stosw
;                Get key, if any are entered
Loc7:    Mov    ah,1
    Int    16h
    Jz    Loc8
    Mov    ah,0
    Int    16h
    Jmp    Loc7
Loc8:
;                Leave ...
    Ret

OldOfs    Dw    ?
OldSeg    Dw    ?

    End    Start