modified: 16/modex16/scroll.c

[16.git] / modex16.c

diff --git a/modex16.c b/modex16.c
index f01116b5257fbab4c24267157af17adc0b73ff20..256a08efc13ab1c40897990871bb1d90cba4aeab 100644 (file)
--- a/modex16.c
+++ b/modex16.c
@@ -213,7 +213,62 @@ modexClearRegion(page_t *page, int x, int y, int w, int h, byte  color) {
                JNZ SCAN_START\r
     }\r
 }\r
+
+
+void\r
+modexClearPlayer(page_t *page, int x, int y, int w, int h) {\r
+    word pageOff = (word) page->data;\r
+    word xoff=x/4;       /* xoffset that begins each row */\r
+    word scanCount=w/4;  /* number of iterations per row (excluding right clip)*/\r
+    word poffset = pageOff + y*(page->width/4) + xoff; /* starting offset */\r
+    word nextRow = page->width/4-scanCount-1;  /* loc of next row */\r
+    byte lclip[] = {0x0f, 0x0e, 0x0c, 0x08};  /* clips for rectangles not on 4s */\r
+    byte rclip[] = {0x00, 0x01, 0x03, 0x07};\r
+    byte left = lclip[x&0x03];\r
+    byte right = rclip[(x+w)&0x03];\r
+\r
+    /* handle the case which requires an extra group */\r
+    if((x & 0x03) && !((x+w) & 0x03)) {\r
+      right=0x0f;\r
+    }\r
+\r
+    __asm {\r
+               MOV AX, SCREEN_SEG      ; go to the VGA memory\r
+               MOV ES, AX\r
+               MOV DI, poffset         ; go to the first pixel\r
+               MOV DX, SC_INDEX        ; point to the map mask\r
+               MOV AL, MAP_MASK\r
+               OUT DX, AL\r
+               INC DX\r
+               MOV AL, NULL            ; get ready to write colors\r
+       SCAN_START:\r
+               MOV CX, scanCount       ; count the line\r
+               MOV BL, AL              ; remember color\r
+               MOV AL, left            ; do the left clip\r
+               OUT DX, AL              ; set the left clip\r
+               MOV AL, BL              ; restore color\r
+               STOSB                   ; write the color\r
+               DEC CX\r
+               JZ SCAN_DONE            ; handle 1 group stuff\r
 \r
+               ;-- write the main body of the scanline\r
+               MOV BL, AL              ; remember color\r
+               MOV AL, 0x0f            ; write to all pixels\r
+               OUT DX, AL\r
+               MOV AL, BL              ; restore color\r
+               REP STOSB               ; write the color\r
+       SCAN_DONE:\r
+               MOV BL, AL              ; remeber color\r
+               MOV AL, right\r
+               OUT DX, AL              ; do the right clip\r
+               MOV AL, BL              ; restore color\r
+               STOSB                   ; write pixel\r
+               ADD DI, nextRow         ; go to the next row\r
+               DEC h\r
+               JNZ SCAN_START\r
+    }\r
+}\r
+
 \r
 void\r
 modexDrawBmp(page_t *page, int x, int y, bitmap_t *bmp) {\r