@@ -22,7 +22,7 @@ static Uint8 blending[5][16] = {

 static void

 ppu_clear(Ppu *p)

 {

-	int i;

+	unsigned int i;

 	for(i = 0; i < p->stride * p->height; ++i)

 		p->dat[i] = 0;

 }

@@ -30,8 +30,10 @@ ppu_clear(Ppu *p)

 unsigned int

 ppu_pixel(Ppu *p, int fg, Uint16 x, Uint16 y, Uint8 color)

 {

-	unsigned int i = x / PPW + y * p->stride, shift = x % PPW * 4;

-	unsigned int ret = p->dat[i];

+	unsigned int ret, i = x / PPW + y * p->stride, shift = x % PPW * 4;

+	if(x >= p->width || y >= p->height)

+		return 0;

+	ret = p->dat[i];

 	if(fg) shift += 2;

 	p->dat[i] &= ~(3 << shift);

 	p->dat[i] |= color << shift;