@@ -12,12 +12,6 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 WITH REGARD TO THIS SOFTWARE.

 */

-/*

-pixel 0001 0002

-layer fgbg fgbg

-byte  1010 1010

-*/

-

 static Uint8 blending[5][16] = {

 	{0, 0, 0, 0, 1, 0, 1, 1, 2, 2, 0, 2, 3, 3, 3, 0},

 	{0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3},

@@ -28,45 +22,44 @@ static Uint8 blending[5][16] = {

 static void

 ppu_clear(Ppu *p)

 {

-	int row;

-	for(row = 0; row < p->height * p->width / 2; ++row)

+	Uint32 row, bound = p->height * p->width / 2;

+	for(row = 0; row < bound; ++row)

 		p->pixels[row] = 0;

 }

+Uint8

+ppu_set_size(Ppu *p, Uint16 width, Uint16 height)

+{

+	ppu_clear(p);

+	p->width = width;

+	p->height = height;

+	p->pixels = realloc(p->pixels, p->width * p->height * sizeof(Uint8) / 2);

+	ppu_clear(p);

+	return !!p->pixels;

+}

+

 Uint8

 ppu_read(Ppu *p, Uint16 x, Uint16 y)

 {

-	int row = (x + y * p->width) / 0x2;

-	Uint8 seg = !(x & 0x1) << 2;

-	Uint8 byte = p->pixels[row] >> seg;

-	return (byte & 0x0c ? (byte >> 2) : byte) & 0x3;

+	Uint32 row = (x + y * p->width) / 0x2;

+	Uint8 shift = !(x & 0x1) << 2;

+	Uint8 pix = p->pixels[row] >> shift;

+	if(pix & 0x0c)

+		pix = pix >> 2;

+	return pix & 0x3;

 }

 void

 ppu_write(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color)

 {

-	int row = (x + y * p->width) / 0x2;

-	Uint8 original = p->pixels[row];

-	Uint8 next = 0x0;

-	if(x % 2) {

-		if(layer) {

-			next |= original & 0xf3;

-			next |= color << 0x02;

-		} else {

-			next |= original & 0xfc;

-			next |= color;

-		}

-	} else {

-		if(layer) {

-			next |= original & 0x3f;

-			next |= color << 0x06;

-		} else {

-			next |= original & 0xcf;

-			next |= color << 0x04;

-		}

-	}

-	p->pixels[row] = next;

-	if(original != next)

+	Uint32 row = (x + y * p->width) / 0x2;

+	Uint8 shift = (!(x & 0x1) << 2) + (layer << 1);

+	Uint8 pix = p->pixels[row];

+	Uint8 mask = ~(0x3 << shift);

+	Uint8 pixnew = (pix & mask) + (color << shift);

+	if(x < p->width && y < p->height)

+		p->pixels[row] = pixnew;

+	if(pix != pixnew)

 		p->reqdraw = 1;

 }

@@ -103,16 +96,3 @@ ppu_2bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Ui

 					blending[ch][color]);

 		}

 }

-

-/* output */

-

-int

-ppu_set_size(Ppu *p, Uint16 width, Uint16 height)

-{

-	ppu_clear(p);

-	p->width = width;

-	p->height = height;

-	p->pixels = realloc(p->pixels, p->width * p->height * sizeof(Uint8) / 2);

-	ppu_clear(p);

-	return !!p->pixels;

-}

@@ -13,10 +13,6 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 WITH REGARD TO THIS SOFTWARE.

 */

-/* pixels per word in ppu.dat */

-

-#define PPW (sizeof(unsigned int) * 2)

-

 typedef unsigned char Uint8;

 typedef unsigned short Uint16;

 typedef unsigned int Uint32;

@@ -26,10 +22,9 @@ typedef struct Ppu {

 	Uint16 width, height;

 } Ppu;

+Uint8 ppu_set_size(Ppu *p, Uint16 width, Uint16 height);

 Uint8 ppu_read(Ppu *p, Uint16 x, Uint16 y);

 void ppu_write(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color);

 void ppu_frame(Ppu *p);

-

 void ppu_1bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy);

 void ppu_2bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy);

-int ppu_set_size(Ppu *p, Uint16 width, Uint16 height);

@@ -121,13 +121,6 @@ set_palette(Uint8 *addr)

 	ppu.reqdraw = 1;

 }

-static void

-set_inspect(Uint8 flag)

-{

-	devsystem->dat[0xe] = flag;

-	ppu.reqdraw = 1;

-}

-

 static void

 set_window_size(SDL_Window *window, int w, int h)

 {

@@ -191,7 +184,6 @@ static void

 draw_inspect(Ppu *p, Uint8 *stack, Uint8 wptr, Uint8 rptr, Uint8 *memory)

 {

 	Uint8 i, x, y, b;

-

 	for(i = 0; i < 0x20; ++i) {

 		x = ((i % 8) * 3 + 1) * 8, y = (i / 8 + 1) * 8, b = stack[i];

 		/* working stack */

@@ -324,7 +316,7 @@ doctrl(SDL_Event *event, int z)

 	case SDLK_LEFT: flag = 0x40; break;

 	case SDLK_RIGHT: flag = 0x80; break;

 	case SDLK_F1: if(z) set_zoom(zoom > 2 ? 1 : zoom + 1); break;

-	case SDLK_F2: if(z) set_inspect(!devsystem->dat[0xe]); break;

+	case SDLK_F2: if(z) devsystem->dat[0xe] = !devsystem->dat[0xe]; break;

 	case SDLK_F3: if(z) capture_screen(); break;

 	}

 	/* clang-format on */

@@ -391,7 +383,7 @@ screen_talk(Device *d, Uint8 b0, Uint8 w)

 			Uint16 x = peek16(d->dat, 0x8);

 			Uint16 y = peek16(d->dat, 0xa);

 			Uint8 layer = d->dat[0xe] & 0x40;

-			ppu_write(&ppu, layer, x, y, d->dat[0xe] & 0x3);

+			ppu_write(&ppu, !!layer, x, y, d->dat[0xe] & 0x3);

 			if(d->dat[0x6] & 0x01) poke16(d->dat, 0x8, x + 1); /* auto x+1 */

 			if(d->dat[0x6] & 0x02) poke16(d->dat, 0xa, y + 1); /* auto y+1 */

 			break;

@@ -402,10 +394,10 @@ screen_talk(Device *d, Uint8 b0, Uint8 w)

 			Uint8 layer = d->dat[0xf] & 0x40;

 			Uint8 *addr = &d->mem[peek16(d->dat, 0xc)];

 			if(d->dat[0xf] & 0x80) {

-				ppu_2bpp(&ppu, layer, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

+				ppu_2bpp(&ppu, !!layer, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

 				if(d->dat[0x6] & 0x04) poke16(d->dat, 0xc, peek16(d->dat, 0xc) + 16); /* auto addr+16 */

 			} else {

-				ppu_1bpp(&ppu, layer, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

+				ppu_1bpp(&ppu, !!layer, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

 				if(d->dat[0x6] & 0x04) poke16(d->dat, 0xc, peek16(d->dat, 0xc) + 8); /* auto addr+8 */

 			}

 			if(d->dat[0x6] & 0x01) poke16(d->dat, 0x8, x + 8); /* auto x+8 */