Added fill_rectangle, draws a filled block of pixes

src/graphics_32.asm

@@ -365,3 +365,80 @@ pub draw_line:
     pop r9
     pop r8
     jmp r13 ; return
+
+
+pub fill_rectangle:
+; void fill_rectangle(u32 fill color, u16 left, u16 top, u16 right, u16 bottom)
+; Draws a rectangle from (left,top) to (right,bottom) with the outline in `border_color`.
+; Fills it with `fill_color`
+; Arguments:
+; - r1: Fill color 24 bit RGB0
+; - r2: Left coord
+; - r3: Top coord
+; - r4: Right coord
+; - r5: Bottom coord
+; Returns:
+; - r1: Color 24 bit RGB0   PRESERVED???
+; - r2: X1 coord
+; - r3: Y1 coord
+; Clobbers:
+; - r4-r7, flags
+; - r5: draw_pixel
+; - r6: draw_pixel
+; Globals read:
+; - FB_DRAW_PTR
+; - FB_DRAW_STRIDE
+
+
+    push r8 ;
+    push r9 ;
+    push r10 ;
+
+    ; Compute start and end pixel addresses of first row
+    load_8 flags, [globals.FB_LOG_WIDTH]
+    lsl r7, r5, flags ; bottom * width
+    lsl r5, r3, flags ; top * width
+    add r6, r5, r4 ; top * width + right
+    add r5, r5, r2 ; top * width + left
+    add r7, r7, r4 ; bottom * width + right
+    lsl r6, r6, 2 ; scale pixel to bytes (LOG_BBP)
+    lsl r5, r5, 2 ; scale pixel to bytes (LOG_BBP)
+    lsl r7, r7, 2 ; scale pixel to bytes (LOG_BBP)
+    load_32 flags, [globals.FB_DRAW_PTR]
+    add r7, r7, flags ; bottom_right_ptr += frambuffer_ptr
+    add r6, r6, flags ; row_end_ptr += frambuffer_ptr
+    add r5, r5, flags ; pixel_ptr += frambuffer_ptr
+
+    
+    mov r8, 4 ; X increment
+    mov r10, 1
+    load_8 flags, [globals.FB_LOG_WIDTH]
+    lsl r10, r10, flags ; screen width
+    sub r9, r10, r4
+    add r9, r9, r2 ; Y wraparound = screen_width - (right-left)
+    lsl r9, r9, 2 ; scale pixel to bytes (LOG_BBP)
+    lsl r10, r10, 2 ; scale pixel to bytes (LOG_BBP)
+    
+    
+    jmp fill_rectangle__loop_in
+    ; For each row
+    fill_rectangle__loop_y:
+        add r5, r5, r9 ; move to start of next row
+        add r6, r6, r10 ; move end_ptr down 1 row
+    fill_rectangle__loop_in:
+        ; Draw pixel
+        store_32 [r5], r1
+        ; Fill rest of the row
+        fill_rectangle__loop_x:
+            add r5, r5, r8
+            ; Draw pixel
+            store_32 [r5], r1
+            cmp r5, r6
+            jb fill_rectangle__loop_x
+        cmp r5, r7
+        jb fill_rectangle__loop_y
+
+    pop r10
+    pop r9
+    pop r8
+    jmp r13 ; return