vga256.pas

dos下经典游戏超级马力的完整源代码

        mov     al, MAP_MASK
        mov     dx, SC_INDEX
        out     dx, ax

        cld
        push    di
        mov     bx, Width
        shr     bx, 1
        shr     bx, 1
        mov     ax, BYTES_PER_LINE
        sub     ax, bx                  { Space before next line }
        mov     dx, Height
  @Line:
        mov     cx, bx
        shr     cx, 1

        push    ax
        pushf

  @Pixel:
        lodsw
        or      al, al
        jz      @Skip1
        seges
        mov     [di], al
  @Skip1:
        inc     di
        or      ah, ah
        jz      @Skip2
        seges
        mov     [di], ah
  @Skip2:
        inc     di
        loop    @Pixel

        popf
        rcl     cx, 1
        jcxz    @Skip3

        lodsb
        or      al, al
        jz      @Odd
        stosb
        jmp     @Skip3
  @Odd: inc     di
  @Skip3:
        pop     ax
        add     di, ax
        dec     dx
        jnz     @Line

        pop     di

        pop     ax
        mov     al, ah
        mov     cl, 4
        shl     al, cl
        or      ah, al                  { Mask for next byte }
        rol     ah, 1                   { Bit mask for next plane }
        pop     cx                      { Planes }
        pop     bx
        inc     bl                      { Still in the same byte? }
        adc     di, 0
        loop    @Plane

    @End:
        pop     ds
    end;
  end;

  procedure RecolorImage (XPos, YPos, Width, Height: Integer; var BitMap; Diff: Byte);
  begin
    asm
        push    ds

        mov     ax, VGA_SEGMENT
        mov     es, ax

        mov     ax, YPos
        cmp     ax, VIR_SCREEN_HEIGHT
        jb      @NotNeg
        jg      @End
        mov     bx, ax
        add     bx, Height
        jnc     @End
  @NotNeg:
        mov     bx, BYTES_PER_LINE
        mul     bx
        mov     di, XPos
        mov     bx, di
        shr     di, 1
        shr     di, 1
        add     di, ax                  { DI = (YPos * 80) + XPos / 4 }
        add     di, PageOffset

        lds     si, BitMap              { Point to bitmap }

        and     bl, 3
        mov     cl, bl
        mov     ah, 1
        shl     ah, cl
        sub     bl, 4
        mov     cx, 4                   { 4 planes }

  @Plane:
        push    bx
        push    cx                      { Planes to go }
        push    ax                      { Mask in AH }

        mov     al, MAP_MASK
        mov     dx, SC_INDEX
        out     dx, ax

        cld
        push    di
        mov     bx, Width
        shr     bx, 1
        shr     bx, 1
        mov     ax, BYTES_PER_LINE
        sub     ax, bx                  { Space before next line }
        mov     dx, Height
  @Line:
        mov     cx, bx
        shr     cx, 1

        push    ax
        pushf

  @Pixel:
        lodsw
        or      al, al
        jz      @Skip1
        add     al, Diff
        seges
        mov     [di], al
  @Skip1:
        inc     di
        or      ah, ah
        jz      @Skip2
        add     ah, Diff
        seges
        mov     [di], ah
  @Skip2:
        inc     di
        loop    @Pixel

        popf
        rcl     cx, 1
        jcxz    @Skip3

        lodsb
        or      al, al
        jz      @Odd
        add     al, Diff
        stosb
        jmp     @Skip3
  @Odd: inc     di
  @Skip3:
        pop     ax
        add     di, ax
        dec     dx
        jnz     @Line

        pop     di

        pop     ax
        mov     al, ah
        mov     cl, 4
        shl     al, cl
        or      ah, al                  { Mask for next byte }
        rol     ah, 1                   { Bit mask for next plane }
        pop     cx                      { Planes }
        pop     bx
        inc     bl                      { Still in the same byte? }
        adc     di, 0
        loop    @Plane

    @End:
        pop     ds
    end;
  end;

  procedure DrawPart (XPos, YPos, Width, Height, Y1, Y2: Integer; var BitMap);
  begin
    asm
        push    ds
        cmp     Height, 0
        jle     @End

        mov     ax, VGA_SEGMENT
        mov     es, ax

        mov     ax, YPos
        cmp     ax, VIR_SCREEN_HEIGHT
        jb      @NotNeg
        jg      @End
        mov     bx, ax
        add     bx, Height
        jnc     @End
  @NotNeg:
        mov     bx, BYTES_PER_LINE
        mul     bx
        mov     di, XPos
        mov     bx, di
        shr     di, 1
        shr     di, 1
        add     di, ax                  { DI = (YPos * 80) + XPos / 4 }
        add     di, PageOffset

        lds     si, BitMap              { Point to bitmap }

        and     bl, 3
        mov     cl, bl
        mov     ah, 1
        shl     ah, cl
        sub     bl, 4
        mov     cx, 4                   { 4 planes }

  @Plane:
        push    bx
        push    cx                      { Planes to go }
        push    ax                      { Mask in AH }

        mov     al, MAP_MASK
        mov     dx, SC_INDEX
        out     dx, ax

        cld
        push    di
        mov     bx, Width
        shr     bx, 1
        shr     bx, 1
        mov     ax, BYTES_PER_LINE
        sub     ax, bx                  { Space before next line }

        xor     dx, dx
  @Line:
        cmp     dx, Y1
        jl      @EndLine
        cmp     dx, Y2
        jg      @EndLine

        mov     cx, bx
        shr     cx, 1

        push    ax
        pushf

  @Pixel:
        lodsw
        or      al, al
        jz      @Skip1
        seges
        mov     [di], al
  @Skip1:
        inc     di
        or      ah, ah
        jz      @Skip2
        seges
        mov     [di], ah
  @Skip2:
        inc     di
        loop    @Pixel

        popf
        rcl     cx, 1
        jcxz    @Skip3

        lodsb
        or      al, al
        jz      @Odd
        stosb
        jmp     @Skip3
  @Odd: inc     di
  @Skip3:
        pop     ax
        add     di, ax
        jmp     @1

  @EndLine:
        add     si, bx
        add     di, BYTES_PER_LINE

  @1:   inc     dx
        cmp     dx, Height
        jb      @Line

        pop     di

        pop     ax
        mov     al, ah
        mov     cl, 4
        shl     al, cl
        or      ah, al                  { Mask for next byte }
        rol     ah, 1                   { Bit mask for next plane }
        pop     cx                      { Planes }
        pop     bx
        inc     bl                      { Still in the same byte? }
        adc     di, 0
        loop    @Plane

  @End:
        pop     ds
    end;
  end;

  procedure UpSideDown (XPos, YPos, Width, Height: Integer; var BitMap);
    { Draw an image on the screen up-side-down (NULL-bytes are ignored) }
  begin
    asm
        push    ds

        mov     ax, VGA_SEGMENT
        mov     es, ax

        mov     ax, YPos
        cmp     ax, VIR_SCREEN_HEIGHT
        jb      @NotNeg
        jg      @End
        mov     bx, ax
        add     bx, Height
        jnc     @End
  @NotNeg:
        add     ax, Height
        dec     ax
        mov     bx, BYTES_PER_LINE
        mul     bx
        mov     di, XPos
        mov     bx, di
        shr     di, 1
        shr     di, 1
        add     di, ax                  { DI = (YPos * 80) + XPos / 4 }
        add     di, PageOffset

        lds     si, BitMap              { Point to bitmap }

        and     bl, 3
        mov     cl, bl
        mov     ah, 1
        shl     ah, cl
        sub     bl, 4
        mov     cx, 4                   { 4 planes }

  @Plane:
        push    bx
        push    cx                      { Planes to go }
        push    ax                      { Mask in AH }

        mov     al, MAP_MASK
        mov     dx, SC_INDEX
        out     dx, ax

        cld
        push    di
        mov     bx, Width
        shr     bx, 1
        shr     bx, 1
        mov     ax, BYTES_PER_LINE
        add     ax, bx                  { Space before next line }
        mov     dx, Height
  @Line:
        mov     cx, bx
        shr     cx, 1

        push    ax
        pushf

  @Pixel:
        lodsw
        or      al, al
        jz      @Skip1
        seges
        mov     [di], al
  @Skip1:
        inc     di
        or      ah, ah
        jz      @Skip2
        seges
        mov     [di], ah
  @Skip2:
        inc     di
        loop    @Pixel

        popf
        rcl     cx, 1
        jcxz    @Skip3

        lodsb
        or      al, al
        jz      @Odd
        stosb
        jmp     @Skip3
  @Odd: inc     di
  @Skip3:
        pop     ax
        sub     di, ax
        dec     dx
        jnz     @Line

        pop     di

        pop     ax
        mov     al, ah
        mov     cl, 4
        shl     al, cl
        or      ah, al                  { Mask for next byte }
        rol     ah, 1                   { Bit mask for next plane }
        pop     cx                      { Planes }
        pop     bx
        inc     bl                      { Still in the same byte? }
        adc     di, 0
        loop    @Plane
  @End:
        pop     ds
    end;
  end;

  procedure PutImage (XPos, YPos, Width, Height: Integer; var BitMap);
    { Draw an image on the screen (NULL-bytes are NOT ignored) }
  begin
    asm
        push    ds
        push    es
        mov     ax, VGA_SEGMENT
        mov     es, ax

        mov     ax, YPos
        mov     bx, BYTES_PER_LINE
        mul     bx
        mov     di, XPos
        mov     bx, di
        shr     di, 1
        shr     di, 1
        add     di, ax                  { DI = (YPos * 80) + XPos / 4 }
        add     di, PageOffset

        lds     si, BitMap              { Point to bitmap }

        and     bl, 3
        mov     cl, bl
        mov     ah, 1
        shl     ah, cl
        sub     bl, 4
        mov     cx, 4                   { 4 planes }

  @Plane:
        push    bx
        push    cx                      { Planes to go }
        push    ax                      { Mask in AH }

        mov     al, MAP_MASK
        mov     dx, SC_INDEX
        out     dx, ax

        cld
        push    di
        mov     bx, Width
        shr     bx, 1
        shr     bx, 1
        mov     ax, BYTES_PER_LINE
        sub     ax, bx                  { Space before next line }
        mov     dx, Height
  @Line:
        mov     cx, bx
        shr     cx, 1
        rep     movsw
        rcl     cx, 1
        rep     movsb
        add     di, ax
        dec     dx
        jnz     @Line

        pop     di

        pop     ax
        mov     al, ah
        mov     cl, 4
        shl     al, cl
        or      ah, al                  { Mask for next byte }
        rol     ah, 1                   { Bit mask for next plane }
        pop     cx                      { Planes }
        pop     bx
        inc     bl                      { Still in the same byte? }
        adc     di, 0
        loop    @Plane


        pop     es
        pop     ds
    end;
  end;


  procedure GetImage (XPos, YPos, Width, Height: Integer; var BitMap);
  begin
    asm
        push    ds
        push    es

        mov     cx, PageOffset

        mov     ax, VGA_SEGMENT
        mov     ds, ax

        mov     ax, YPos
        mov     bx, BYTES_PER_LINE
        mul     bx
        mov     si, XPos
        mov     bx, si
        shr     si, 1
        shr     si, 1