modified: 16/MODEX16.ZIP

[16.git] / 16 / modex16 / modex16.c

diff --git a/16/modex16/modex16.c b/16/modex16/modex16.c
index bdc089e524a5330fb7bebff27fac01ff86238771..71537b6672a3a37f2cb7561003365f380aafb52c 100644 (file)
--- a/16/modex16/modex16.c
+++ b/16/modex16/modex16.c
@@ -384,13 +384,76 @@ modexDrawSpriteRegion(page_t *page, int x, int y,
 }\r
 \r
 \r
+/* copy a region of video memory from one page to another.\r
+ * It assumes that the left edge of the tile is the same on both\r
+ * regions and the memory areas do not overlap.\r
+ */\r
 void\r
-modexCopyPageRegion(page_t *dest, page_t src,\r
+modexCopyPageRegion(page_t *dest, page_t *src,\r
                    word sx, word sy,\r
                    word dx, word dy,\r
                    word width, word height)\r
 {\r
-    /* todo */\r
+    word doffset = (word)dest->data + dy*(dest->width/4) + dx/4;\r
+    word soffset = (word)src->data + sy*(src->width/4) + sx/4;\r
+    word scans   = width/4;\r
+    word nextSrcRow = src->width/4 - scans - 1;\r
+    word nextDestRow = dest->width/4 - scans - 1;\r
+    byte lclip[] = {0x0f, 0x0e, 0x0c, 0x08};  /* clips for rectangles not on 4s */\r
+    byte rclip[] = {0x0f, 0x01, 0x03, 0x07};\r
+    byte left = lclip[sx&0x03];\r
+    byte right = rclip[(sx+width)&0x03];\r
+\r
+    __asm {\r
+               MOV AX, SCREEN_SEG      ; work in the vga space\r
+               MOV ES, AX              ;\r
+               MOV DI, doffset         ;\r
+               MOV SI, soffset         ;\r
+\r
+               MOV DX, GC_INDEX        ; turn off cpu bits\r
+               MOV AX, 0008h           ;\r
+               OUT DX, AX\r
+\r
+               MOV AX, SC_INDEX        ; point to the mask register\r
+               MOV DX, AX              ;\r
+               MOV AL, MAP_MASK        ;\r
+               OUT DX, AL              ;\r
+               INC DX                  ;\r
+\r
+       ROW_START:\r
+               PUSH DS\r
+               MOV AX, ES\r
+               MOV DS, AX\r
+               MOV CX, scans           ; the number of latches\r
+\r
+               MOV AL, left            ; do the left column\r
+               OUT DX, AL              ;\r
+               MOVSB                   ;\r
+               DEC CX                  ;\r
+\r
+               MOV AL, 0fh             ; do the inner columns\r
+               OUT DX, AL\r
+               REP MOVSB               ; copy the pixels\r
+\r
+               MOV AL, right           ; do the right column\r
+               OUT DX, AL\r
+               MOVSB\r
+               POP DS\r
+\r
+               MOV AX, SI              ; go the start of the next row\r
+               ADD AX, nextSrcRow      ;\r
+               MOV SI, AX              ;\r
+               MOV AX, DI              ;\r
+               ADD AX, nextDestRow     ;\r
+               MOV DI, AX              ;\r
+\r
+               DEC height              ; do the rest of the actions\r
+               JNZ ROW_START           ;\r
+\r
+               MOV DX, GC_INDEX+1      ; go back to CPU data\r
+               MOV AL, 0ffh            ; none from latches\r
+               OUT DX, AL              ;\r
+    }\r
 }\r
 \r
 \r