Cleaned up PPU

src/devices/ppu.c

@@ -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;
+	Uint32 row, bound = p->height * p->width / 2;
-	for(row = 0; row < p->height * p->width / 2; ++row)
+	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;
+	Uint32 row = (x + y * p->width) / 0x2;
-	Uint8 seg = !(x & 0x1) << 2;
+	Uint8 shift = !(x & 0x1) << 2;
-	Uint8 byte = p->pixels[row] >> seg;
+	Uint8 pix = p->pixels[row] >> shift;
-	return (byte & 0x0c ? (byte >> 2) : byte) & 0x3;
+	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;
+	Uint32 row = (x + y * p->width) / 0x2;
-	Uint8 original = p->pixels[row];
+	Uint8 shift = (!(x & 0x1) << 2) + (layer << 1);
-	Uint8 next = 0x0;
+	Uint8 pix = p->pixels[row];
-	if(x % 2) {
+	Uint8 mask = ~(0x3 << shift);
-		if(layer) {
+	Uint8 pixnew = (pix & mask) + (color << shift);
-			next |= original & 0xf3;
+	if(x < p->width && y < p->height)
-			next |= color << 0x02;
+		p->pixels[row] = pixnew;
-		} else {
+	if(pix != pixnew)
-			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)
 		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;
-}

src/devices/ppu.h

@@ -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);

src/uxnemu.c

@@ -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 */