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[16.git] / 16 / x_ / mxgi.asm

diff --git a/16/x_/mxgi.asm b/16/x_/mxgi.asm
new file mode 100755 (executable)
index 0000000..7037d41
--- /dev/null
+++ b/16/x_/mxgi.asm
@@ -0,0 +1,132 @@
+;-----------------------------------------------------------\r
+;\r
+; MXGI.ASM - Get image\r
+; Copyright (c) 1994 by Alessandro Scotti\r
+;\r
+;-----------------------------------------------------------\r
+WARN    PRO\r
+NOWARN  RES\r
+INCLUDE MODEX.DEF\r
+\r
+PUBLIC  mxGetImage\r
+\r
+EXTRN   subClipImage            : NEAR\r
+\r
+MX_TEXT         SEGMENT USE16 PARA PUBLIC 'CODE'\r
+                ASSUME cs:MX_TEXT, ds:NOTHING, es:NOTHING\r
+\r
+EXTRN   mx_VideoSegment : WORD\r
+EXTRN   mx_BytesPerLine : WORD\r
+\r
+;-----------------------------------------------------------\r
+;\r
+; Copies an image from screen to memory.\r
+;\r
+; Input:\r
+;       Image   = pointer to buffer for image\r
+;       X, Y    = coordinates of image on screen\r
+;       Width   = width of image in pixels\r
+;       Height  = height of image in pixels\r
+; Output:\r
+;       none\r
+;\r
+mxGetImage      PROC    FAR\r
+        ARG     Height:WORD,            \\r
+                Width:WORD,             \\r
+                Y:WORD,                 \\r
+                X:WORD,                 \\r
+                Image:DWORD             = ARG_SIZE\r
+        LOCAL   PlaneWidth:WORD:4,      \\r
+                PixelOffset:WORD,       \\r
+                MoveFunction:WORD,      \\r
+                ReadPlane:BYTE,         \\r
+                Count:BYTE              = AUTO_SIZE\r
+        ASSUME  ds:NOTHING\r
+        .enter  AUTO_SIZE\r
+        .push   ds, si, es, di\r
+\r
+; Clip image\r
+        mov     bx, [X]\r
+        mov     ax, [Y]\r
+        mov     cx, [Width]\r
+        mov     dx, [Height]\r
+        call    subClipImage\r
+        jc      @@Exit                  ; Full clipped\r
+        mov     [Height], dx\r
+        add     WORD PTR Image[0], si   ; Skip clipped pixels\r
+\r
+; Get pixel address\r
+        mul     [mx_BytesPerLine]\r
+        mov     si, bx\r
+        shr     si, 1\r
+        shr     si, 1\r
+        add     si, ax\r
+        mov     [PixelOffset], si\r
+        mov     ds, [mx_VideoSegment]   ; DS:SI points to pixel\r
+        and     bl, 03h\r
+        mov     [ReadPlane], bl\r
+\r
+; Compute extra bytes and width count for each plane\r
+        mov     bx, cx\r
+        shr     bx, 1\r
+        shr     bx, 1                   ; Width for each plane\r
+        and     cl, 03h\r
+        mov     al, 00001000b\r
+        shr     al, cl\r
+        mov     di, 3 SHL 1\r
+@@PatchLoop:\r
+        mov     PlaneWidth[di], bx\r
+        shr     al, 1\r
+        adc     bx, 0\r
+        dec     di\r
+        dec     di\r
+        jge     @@PatchLoop\r
+\r
+; Get image\r
+        cld\r
+        mov     [Count], 4              ; Four planes\r
+        lea     bx, PlaneWidth          ; SS:[BX] = width in bytes for plane\r
+        mov     es, WORD PTR Image[2]   ; ES:DI will point to image\r
+        mov     ah, [ReadPlane]\r
+@@PlaneLoop:\r
+        cmp     WORD PTR ss:[bx], 0     ; Exit if nothing more to do\r
+        je      @@Exit                  ; (also, never try to move zero bytes!)\r
+        mov     di, WORD PTR Image[0]\r
+        mov     al, 04h\r
+        mov     dx, GDC\r
+        out     dx, ax                  ; Select read plane\r
+        mov     dx, [Height]\r
+        mov     si, [PixelOffset]       ; DS:SI points to video memory\r
+@@Loop:\r
+        .push   si, di\r
+        mov     cx, WORD PTR ss:[bx]    ; Number of bytes to move\r
+@@MoveLoop:\r
+        movsb\r
+        add     di, 3\r
+        dec     cx\r
+        jnz     @@MoveLoop\r
+        .pop    si, di\r
+        add     di, [Width]             ; Go to next image line\r
+        add     si, [mx_BytesPerLine]   ; Go to next screen row\r
+        dec     dx\r
+        jnz     @@Loop                  ; Repeat for all lines\r
+        inc     bx\r
+        inc     bx                      ; Select width for next plane\r
+        inc     ah\r
+        test    ah, 04h                 ; Plane wraparound?\r
+        jz      @@PlaneOk               ; No\r
+        inc     [PixelOffset]           ; Yes, bump video pointer\r
+        and     ah, 03h\r
+@@PlaneOk:\r
+        inc     WORD PTR Image[0]\r
+        dec     [Count]\r
+        jnz     @@PlaneLoop             ; Repeat for all planes\r
+\r
+@@Exit:\r
+        xor     ax, ax\r
+        .pop    ds, si, es, di\r
+        .leave  ARG_SIZE\r
+mxGetImage      ENDP\r
+\r
+MX_TEXT         ENDS\r
+END\r