Assembly 1994 - The 3rd Phase/ASMROM94.mdf/fc/utils/stmik/misc.asm

Assembly Source File | 1991-07-03 | 3KB | 240 lines

; miscellaneous routines

seed1    dw    1234
seed2    dw    5678
seed3    dw    1234h
seed4    dw    5678h

rand    PROC    NEAR
    push    bx
    push    cx
    push    dx
    mov    ax,ds:seed1
    mov    bx,ds:seed2
    mov    cx,ds:seed3
    mov    dx,ds:seed4
    add    ax,bx
    rol    ax,cl
    xor    ax,dx
    xchg    cl,ch
    add    bx,cx
    add    dx,bx
    add    cx,ax
    ror    bx,1
    sbb    ax,dx
    mov    ds:seed4,dx
    mov    ds:seed3,dx
    mov    ds:seed2,dx
    mov    ds:seed1,ax
    pop    dx
    pop    cx
    pop    bx
    ret
rand    ENDP

waitborder PROC NEAR
    push    ax
    push    dx
    mov    dx,3dah
wbr1:    in    al,dx
    test    al,8
    jnz    wbr1
wbr2:    in    al,dx
    test    al,8
    jz    wbr2
    pop    dx
    pop    ax
    ret
waitborder ENDP

tmppal    db    768 dup(0)

fadeoffpalette PROC NEAR
    mov    bh,2
    mov    ah,0
    jmp    fadepalette
fadeoffpalette ENDP

fadeonpalette PROC NEAR
    mov    bh,-2
    mov    ah,64
fadepalette:
    mov    dx,cs
    mov    ds,dx
    mov    es,dx

    mov    cx,32
fonp2:    push    ax
    push    cx
    push    si
    mov    di,OFFSET tmppal
    mov    cx,768
fonp1:    lodsb
    sub    al,ah
    jnc    fonp3
    xor    al,al
fonp3:    stosb
    loop    fonp1
    mov    si,OFFSET tmppal
    mov    cx,768/6/2
    sti
    call    waitborder
    cli
    mov    dx,3c8h
    xor    al,al
    out    dx,al
    inc    dx
    cli
fonp4:    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    loop    fonp4
    sti
    mov    cx,768/6/2
    call    waitborder
    cli
fonp5:    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    lodsb
    out    dx,al
    loop    fonp5
    sti
    pop    si
    pop    cx
    pop    ax
    add    ah,bh
    loop    fonp2
    ret
fadeonpalette ENDP

sine    MACRO ;ax=sin(ax)*32768
    push    bx
    and    ax,255
    shl    ax,1
    mov    bx,ax
    mov    ax,cs:sintable[bx]
    pop    bx
    ENDM

cosine    MACRO ;ax=cos(ax)*32768
    push    bx
    add    ax,64
    and    ax,255
    shl    ax,1
    mov    bx,ax
    mov    ax,cs:sintable[bx]
    pop    bx
    ENDM

getrasterline PROC NEAR
    ;AX=scan line the VGA is in (requires ints set)
    cli
    xor    al,al
    out    43h,al
    in    al,40h
    mov    dl,al
    in    al,40h
    mov    dh,al
    shr    dx,1
    mov    ax,cs:frametime
    sub    ax,dx
    mov    cx,400
    mul    cx
    mov    cx,cs:frametime
    div    cx
    sti
    ret
getrasterline ENDP

tmpseg    dw    0
filerquit db    1
loadfile    PROC    NEAR
        ;set: DX=offset to filename
        ;set: AX=minimum paragraphs reserved
        ;return: DX=segment of file
        mov    bp,ax
        mov    ax,cs
        mov    ds,ax ;set ds=cs
        mov    ah,3dh ;open file
        mov    al,0 ;read only
        int    21h
        jc    ferror
        mov    bx,ax ;store filehandle to bx
        ;get length of file (seek to end)
        mov    ah,42h
        mov    al,2
        mov    cx,0
        mov    dx,0
        int    21h
        jc    ferror
        ;get memory
        push    bx
        shr    dx,1
        rcr    ax,1
        shr    dx,1
        rcr    ax,1
        shr    dx,1
        rcr    ax,1
        shr    dx,1
        rcr    ax,1
        mov    bx,ax
        inc    bx ;one extra, just in case :-)
        cmp    bx,bp
        ja    loff1
        mov    bx,bp
loff1:        mov    ah,48h
        int    21h
        jc    ferror
        mov    cs:tmpseg,ax
        pop    bx
        ;Seek file back to the beginning
        mov    ah,42h
        mov    al,0
        mov    cx,0
        mov    dx,0
        int    21h
        jc    ferror
        ;read file
        mov    ds,cs:tmpseg
faga:        mov    ah,3fh
        mov    cx,32768
        mov    dx,0
        int    21h
        jc    ferror
        mov    dx,ds
        add    dx,800h
        mov    ds,dx
        cmp    ax,32768
        je    faga
        ;close file
        mov    ah,3eh
        int    21h
        mov    dx,cs:tmpseg ;segment
        xor    ax,ax
        ret
ferror2:    mov    ax,1
        ret
ferror:        cmp    cs:filerquit,0
        je    ferror2
        mov    ax,4c01h
        int    21h
loadfile    ENDP