HPAVC/HPAVC CD-ROM.iso/pc/ZOOM_EX.ZIP/ZOOM2.ASM

Assembly Source File | 1993-12-25 | 6.2 KB | 279 lines

;                                                       (C)ode by Nic of IMP

JUMPS
SMART
LOCALS
DOSSEG

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Time    =       0       ; to show time equal this to unity

; some usefull macro's

; only for Motorola freaks !

movB    MACRO    dst,src
    mov BYTE PTR    dst,src
    ENDM

movW    MACRO    dst,src
    mov WORD PTR    dst,src
    ENDM

movL    MACRO    dst,src
    mov DWORD PTR    dst,src
    ENDM

WaitKey MACRO
    mov    ah,7
    int    21h
    ENDM

PrintString MACRO String
    mov    dx,OFFSET String
    mov    ah,9
    int    21h
    ENDM

Exit2Dos MACRO    ErrCode
    mov    ax,4c00h+ErrCode
    int    21h
    ENDM

Color   MACRO   Num,RComp,GComp,BComp
        push    dx
        push    ax
        mov     dx,3c8h
        mov     al,Num
        out     dx,al
        mov     dx,3c9h
        mov     al,RComp
        out     dx,al
        mov     al,GComp
        out     dx,al
        mov     al,BComp
        out     dx,al
        pop     ax
        pop     dx
        ENDM

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StackSeg    Segment Para USE16 STACK 'STACK'
    DW    512 DUP (?)
StackSeg    Ends

;───────────────────────────────────────────────────────────────────────────────

DataSeg     Segment Para USE16 'DATA'

CodeString    DB 80 DUP (0)

        ALIGN   16
Picture         LABEL
                INCLUDE TestZoom.pic
                DB 320 DUP (0)

DataSeg     Ends

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CodeSeg     Segment Para USE16 'CODE'
    ASSUME    cs:CodeSeg , ds:DataSeg , ss:StackSeg

Prog    Proc Far
    call    SetFree

    mov    ax,DataSeg
    mov    ds,ax
    mov    es,ax
    cld
        call    InitGfxMode
        call    InstallColors

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        call    TstZoom
;═══════════════════════════════════════════════════════════════════════════════

    WaitKey
        call    RestTxtMode

Finish: Exit2Dos    0

Prog    Endp

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; here, we'll just make a vertical zoom, it is faster, but it's not for that,
; I think it will be easier to understant if you have only one zoom & I've
; tried to keep my code clean & short.

OriginalSize    DW      200
DestinationSize DW      0
Count           DW      ?
LineLength      =       320     ; in bytes

TabLines        LABEL
ALine   = 0
                REPT    200
                DW      ALine
ALine   = ALine + LineLength
                ENDM
                REPT    10
                DW      200*LineLength
                ENDM

TstZoom PROC NEAR

VBLLoop:
        mov     dx,3dah         ; wait VBL
Wait1:  in      al,dx
        test    al,8
        jne     Wait1
Wait2:  in      al,dx
        test    al,8
        je      Wait2

        IF      Time
        Color   0,20,0,0
        ENDIF
                                ; Zoom the Pic
        mov     ax,0a000h
        mov     es,ax
        mov     di,0
        inc     DestinationSize
        cmp     DestinationSize,201
        jl      GoodSize
        mov     DestinationSize,1
        call    ClearScreen
GoodSize:
        mov     cx,DestinationSize
        mov     Count,cx

        mov     dx,0
        mov     ax,OriginalSize
        mov     bx,DestinationSize
        div     bx                      ; ax = dx:ax / bx

        mov     bp,ax
        mov     ax,0
        div     bx

; the 6 following lines are here to make a better approx
        mov     bx,bp
        mov     dx,ax
        shr     bx,1
        rcr     dx,1            ; for approx
        add     dx,08000h
        adc     bx,0            ; + 1/2 for roundness

; increment in          bp:ax
; starting offset in    bx:dx

ZoomLoop:
        mov     si,bx
        add     si,si
        mov     si,TabLines[si]
        add     si,OFFSET Picture

CopyOneLine:
        mov     cx,LineLength/2
        REP     movsw

        add     dx,ax
        adc     bx,bp

        dec     Count
        jnz     ZoomLoop

        IF      Time
        Color   0,0,0,0
        ENDIF
                                ; Zoom the Pic
        in      al,60h          ; read key
        cmp     al,039h
        jne     VBLLoop

        ret
TstZoom ENDP

ClearScreen PROC NEAR
        mov     ax,0a000h
        mov     es,ax
        mov     ax,0
        mov     cx,320*200/2
        REP     stosw
        ret
ClearScreen ENDP

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; release memory

SetFree PROC NEAR
    mov    bx,ss
    mov    ax,es
    sub    bx,ax
    mov    ax,sp
    add    ax,15
    mov    cl,4
    shr    ax,cl
    add    bx,ax
    mov    ah,4ah
    int    21h
    ret
SetFree ENDP

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InstallColors PROC NEAR
        push    ds
        push    cs
        pop     ds
        lea     si,PALETTE
        mov     cx,256
        mov     dx,03c8h
        xor     al,al
        out     dx,al
        inc     dx
        cld
@@ColorLoop:
        lodsb
        shr     al,3
        out     dx,al
        loop    @@ColorLoop
        pop     ds
        ret
InstallColors ENDP

PALETTE LABEL
        INCLUDE testzoom.pal

InitGfxMode PROC NEAR
        mov     ax,13h
        int     10h
        ret
InitGfxMode ENDP

RestTxtMode PROC NEAR
        xor     ah,ah
        mov     al,03h
        int     10h
        ret
RestTxtMode ENDP


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CodeSeg     Ends
    END    Prog