Data commit

Task/Bitmap/ARM-Assembly/bitmap.arm

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+Bitmap_FloodFill:
+	;input:
+	;r0 = color to fill screen with (15-bit color)
+	STMFD sp!,{r0-r12,lr}
+			
+			MOV R2,#160
+			MOV R4,#0x06000000
+outerloop_floodfill:
+			MOV R1,#240               ;restore inner loop counter
+innerloop_floodfill:
+			strH r0,[r4]
+			add r4,r4,#2              ;next pixel
+			subs r1,r1,#1             ;decrement loop counter
+			bne innerloop_floodfill
+			subs r2,r2,#1
+			bne outerloop_floodfill
+	
+	LDMFD sp!,{r0-r12,pc}
+	
+Bitmap_Locate:
+        ;given x and y coordinates, offsets vram addr to that pixel on screen.
+	;input:
+	;r0 = x
+	;r1 = y
+	;output: r2 = vram area
+	STMFD sp!,{r4-r12,lr}
+		mov r2,#0x06000000	;vram base
+
+		
+		mov r4,#240*2          ;240 pixels across, 2 bytes per pixel
+		mul r1,r4,r1
+		add r2,r2,r1          ;add y*480
+		add r2,r2,r0,lsl #1   ;add x*2
+	LDMFD sp!,{r4-r12,pc}
+	
+Bitmap_StorePixel:
+	;input: r3 = color
+	;r0 = x
+	;r1 = y
+	bl Bitmap_Locate
+	strH r3,[r2]                 ;store the pixel color in video memory
+	bx lr
+	
+Bitmap_GetPixel:
+        ;retrieves the color of the pixel at [r2] and stores its color value in r3.
+	;r0 = x
+	;r1 = y
+	;output in r3
+	bl Bitmap_Locate
+	ldrH r3,[r2]
+	bx lr