move read/write prg/chr/cirom data to mapper

1 files changed, 130 insertions, 184 deletions

diff --git a/ppu.c b/ppu.c
index 2c993c9..aff5166 100644
--- a/ppu.c
+++ b/ppu.c
@@ -1,155 +1,127 @@
-static uint8_t memory_read_dma(struct nes_state *state, uint32_t offset);
-
 
-static void ppu_sprite_shift(struct nes_state *state) {
-	struct ppu_state *ppu = &state->ppu;
 
-	if(!(ppu->reg_mask & 0x10)) {
-		return;
-	}
+static uint8_t __attribute__((aligned(64))) ppu_bitreverse_lut[256] = {
+#   define R2(n)     n,     n + 2*64,     n + 1*64,     n + 3*64
+#   define R4(n) R2(n), R2(n + 2*16), R2(n + 1*16), R2(n + 3*16)
+#   define R6(n) R4(n), R4(n + 2*4 ), R4(n + 1*4 ), R4(n + 3*4 )
+    R6(0), R6(2), R6(1), R6(3)
+};
+#undef R2
+#undef R4
+#undef R6
 
-	for(uint32_t i = 0; i < ppu->sprite_count; i++) {
-		if(ppu->sprite_positions[i] > 0) {
-			ppu->sprite_positions[i]--;
-		} else {
-			ppu->sprite_shift_lo[i] <<= 1;
-			ppu->sprite_shift_hi[i] <<= 1;
-		}
-	}
-}
+static uint8_t memory_read_dma(struct nes_state *state, uint32_t offset);
 
 static void ppu_reset(struct nes_state *state) {
 	struct ppu_state *ppu = &state->ppu;
 	memset(ppu, 0, sizeof(struct ppu_state));
 }
 
-static uint32_t ppu_resolve_ciram(struct nes_state *state, uint32_t addr) {
-	addr &= 0x0fff;
-
-	switch(state->ines.mirroring) {
-		case MIRROR_VERTICAL: {
-			// $2000/$2800 → $0000, $2400/$2C00 → $0400
-			return (addr & 0x0400) | (addr & 0x03ff);
-		}
-		case MIRROR_HORIZONTAL: {
-			// $2000/$2400 → $0000, $2800/$2C00 → $0400
-			return ((addr & 0x0800) >> 1) | (addr & 0x03ff);
-		}
-		default: {
-			return addr & 0x07ff;
-		}
-	}
-}
-
-
-static uint8_t ppu_ciram_read(struct nes_state *state, uint32_t addr) {
-	return state->ciram[ppu_resolve_ciram(state, addr)];
-}
-
-static void ppu_ciram_write(struct nes_state *state, uint32_t addr, uint8_t value) {
-	state->ciram[ppu_resolve_ciram(state, addr)] = value;
-}
-
-static void ppu_write_2000(struct nes_state *state, uint8_t value) {
-	struct ppu_state *ppu = &state->ppu;
-	ppu->reg_ctrl = value;
-	ppu->temp_addr = (ppu->temp_addr & 0xf3ff) | ((value & 0x03) << 10);
-}
-
-static void ppu_write_2001(struct nes_state *state, uint8_t value) {
-	state->ppu.reg_mask = value;
-}
-
-static void ppu_write_2003(struct nes_state *state, uint8_t value) {
-	state->ppu.oam_addr = value;
-}
-
-static void ppu_write_2004(struct nes_state *state, uint8_t value) {
-	state->ppu.oam[state->ppu.oam_addr] = value;
-	state->ppu.oam_addr++;
-}
-
-static void ppu_write_2005(struct nes_state *state, uint8_t value) {
-	struct ppu_state *ppu = &state->ppu;
-
-	if(ppu->write_latch == 0) {
-		ppu->fine_x = value & 0x07;
-		ppu->temp_addr = (ppu->temp_addr & ~0x001f) | (value >> 3);
-		ppu->write_latch = 1;
-	} else {
-		ppu->temp_addr = (ppu->temp_addr & ~0x73e0) | ((value & 0x07) << 12) | ((value & 0xf8) << 2);
-		ppu->write_latch = 0;
-	}
-}
-
-static void ppu_write_2006(struct nes_state *state, uint8_t value) {
+static void ppu_write(struct nes_state *state, uint32_t offset, uint8_t value) {
 	struct ppu_state *ppu = &state->ppu;
 
-	if(ppu->write_latch == 0) {
-		ppu->temp_addr = (ppu->temp_addr & 0x00ff) | ((value & 0x3f) << 8);
-		ppu->write_latch = 1;
-	} else {
-		ppu->temp_addr = (ppu->temp_addr & 0xff00) | value;
-		ppu->vram_addr = ppu->temp_addr;
-		ppu->write_latch = 0;
-	}
-}
+	switch(offset & 7) {
+		case 0: {		// 2000
+			ppu->reg_ctrl = value;
+			ppu->temp_addr = (ppu->temp_addr & 0xf3ff) | ((value & 0x03) << 10);
+			ppu->open_bus = value;
+		} break;
+
+		case 1: {		// 2001
+			ppu->reg_mask = value;
+			ppu->open_bus = value;
+		} break;
+
+		case 3: {		// 2003
+			ppu->oam_addr = value;
+		} break;
+
+		case 4: {		// 2004
+			ppu->oam[ppu->oam_addr] = value;
+			ppu->oam_addr++;
+		} break;
+
+		case 5: {		// 2005
+			if(ppu->write_latch == 0) {
+				ppu->fine_x = value & 0x07;
+				ppu->temp_addr = (ppu->temp_addr & ~0x001f) | (value >> 3);
+				ppu->write_latch = 1;
+			} else {
+				ppu->temp_addr = (ppu->temp_addr & ~0x73e0) | ((value & 0x07) << 12) | ((value & 0xf8) << 2);
+				ppu->write_latch = 0;
+			}
+			ppu->open_bus = value;
+		} break;
 
-static void ppu_write_2007(struct nes_state *state, uint8_t value) {
-	struct ppu_state *ppu = &state->ppu;
-	uint32_t addr = ppu->vram_addr & 0x3fff;
-	if(addr < 0x2000) {
-		// CHR-RAM, skip
-	} else if(addr < 0x3f00) {
-		ppu_ciram_write(state, addr, value);
-	} else if(addr < 0x4000) {
-		uint32_t pal_addr = addr & 0x1f;
-		if((pal_addr & 0x13) == 0x10) {
-			pal_addr &= ~0x10;
-		}
-		ppu->palette[pal_addr] = value;
+		case 6: {		// 2006
+			if(ppu->write_latch == 0) {
+				ppu->temp_addr = (ppu->temp_addr & 0x00ff) | ((value & 0x3f) << 8);
+				ppu->write_latch = 1;
+			} else {
+				ppu->temp_addr = (ppu->temp_addr & 0xff00) | value;
+				ppu->vram_addr = ppu->temp_addr;
+				ppu->write_latch = 0;
+			}
+			ppu->open_bus = value;
+		} break;
+
+		case 7: {		// 2007
+			uint32_t addr = ppu->vram_addr & 0x3fff;
+			if(addr < 0x2000) {
+				// CHR-RAM, skip
+			} else if(addr < 0x3f00) {
+				state->mapper.ciram_write(state, addr, value);
+			} else if(addr < 0x4000) {
+				uint32_t pal_addr = addr & 0x1f;
+				if((pal_addr & 0x13) == 0x10) {
+					pal_addr &= ~0x10;
+				}
+				ppu->palette[pal_addr] = value;
+			}
+			ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
+		} break;
 	}
-
-	ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
 }
 
-static uint8_t ppu_read_2002(struct nes_state *state) {
+static uint8_t ppu_read(struct nes_state *state, uint32_t offset) {
 	struct ppu_state *ppu = &state->ppu;
-	uint8_t result = ppu->reg_status;
-
-	ppu->reg_status &= ~0x80;
-	ppu->write_latch = 0;
-
-	return result;
-}
-
-static uint8_t ppu_read_2004(struct nes_state *state) {
-	return state->ppu.oam[state->ppu.oam_addr];
-}
+	uint8_t result = ppu->open_bus;
+
+	switch(offset & 7) {
+		case 2: {		// 2002
+			result = ppu->reg_status;
+			ppu->reg_status &= ~0x80;
+			ppu->write_latch = 0;
+		} break;
+
+		case 4: {		// 2004
+			result = ppu->oam[ppu->oam_addr];
+		} break;
+
+		case 7: {		// 2007
+			uint32_t addr = ppu->vram_addr & 0x3fff;
+			result = 0;
+
+			if(addr < 0x2000) {
+				result = ppu->vram_read_buffer;
+				ppu->vram_read_buffer =  state->mapper.chr_read(state, addr);
+			} else if(addr < 0x3f00) {
+				result = state->mapper.ciram_read(state, addr);
+			} else if(addr < 0x4000) {
+				uint32_t pal_addr = addr & 0x1f;
+				if((pal_addr & 0x13) == 0x10) {
+					pal_addr &= ~0x10;
+				}
+				result = ppu->palette[pal_addr];
+			}
 
-static uint8_t ppu_read_2007(struct nes_state *state) {
-	struct ppu_state *ppu = &state->ppu;
-	uint32_t addr = ppu->vram_addr & 0x3fff;
-	uint8_t result = 0;
-
-	if(addr < 0x2000) {
-		result = ppu->vram_read_buffer;
-		ppu->vram_read_buffer = state->chrrom[addr];
-	} else if(addr < 0x3f00) {
-		result = ppu_ciram_read(state, addr);
-	} else if(addr < 0x4000) {
-		uint32_t pal_addr = addr & 0x1f;
-		if((pal_addr & 0x13) == 0x10) {
-			pal_addr &= ~0x10;
-		}
-		result = ppu->palette[pal_addr];
+			ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
+		} break;
 	}
-
-	ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
+	ppu->open_bus = result;
 	return result;
 }
 
-#if 1
 static void ppu_evaluate_sprites(struct nes_state *state) {
 	struct ppu_state *ppu = &state->ppu;
 	uint8_t sprite_height = (ppu->reg_ctrl & 0x20) ? 16 : 8;
@@ -183,40 +155,6 @@ static void ppu_evaluate_sprites(struct nes_state *state) {
 	ppu->sprite_count = n;
 }
 
-#else
-static void ppu_evaluate_sprites(struct nes_state *state) {
-	struct ppu_state *ppu = &state->ppu;
-	uint8_t sprite_height = (ppu->reg_ctrl & 0x20) ? 16 : 8;
-	uint8_t n = 0;
-
-	for(uint8_t i = 0; i < 64; i++) {
-		uint8_t y = ppu->oam[i * 4 + 0];
-		int row = (int)ppu->scanline - y;
-
-		if(row >= 0 && row < sprite_height) {
-			if(n < 8) {
-				uint8_t *src = ppu->oam + i * 4;
-				uint8_t *dst = ppu->secondary_oam + n * 4;
-				dst[0] = src[0];
-				dst[1] = src[1];
-				dst[2] = src[2];
-				dst[3] = src[3];
-				ppu->sprite_indexes[n] = i;
-				if(i == 0) {
-					ppu->sprite_zero_hit_possible = 1;
-				}
-				n++;
-			} else {
-				ppu->reg_status |= 0x20;
-				break;
-			}
-		}
-	}
-
-	ppu->sprite_count = n;
-}
-#endif
-
 static void ppu_fetch_sprite_patterns(struct nes_state *state) {
 	struct ppu_state *ppu = &state->ppu;
 	for(uint8_t i = 0; i < ppu->sprite_count; i++) {
@@ -225,9 +163,7 @@ static void ppu_fetch_sprite_patterns(struct nes_state *state) {
 		uint8_t row = ppu->scanline - y;
 		uint8_t height = (ppu->reg_ctrl & 0x20) ? 16 : 8;
 
-		if(attr & 0x80) {
-			row = height - 1 - row;
-		}
+		row = (attr & 0x80) ? height - 1 - row : row;
 
 		uint32_t addr;
 		if(height == 16) {
@@ -243,12 +179,12 @@ static void ppu_fetch_sprite_patterns(struct nes_state *state) {
 			addr = bank + tile * 16 + row;
 		}
 
-		uint8_t lsb = state->chrrom[addr];
-		uint8_t msb = state->chrrom[addr + 8];
+		uint8_t lsb = state->mapper.chr_read(state, addr);
+		uint8_t msb = state->mapper.chr_read(state, addr + 8);
 
 		if(attr & 0x40) {
-			lsb = ((lsb * 0x0202020202ULL & 0x010884422010ULL) % 1023) & 0xff;
-			msb = ((msb * 0x0202020202ULL & 0x010884422010ULL) % 1023) & 0xff;
+			lsb = ppu_bitreverse_lut[lsb];
+			msb = ppu_bitreverse_lut[msb];
 		}
 
 		ppu->sprite_shift_lo[i] = lsb;
@@ -272,10 +208,6 @@ static void ppu_render_pixel(struct nes_state *state) {
 	uint32_t x = ppu->dot - 1;
 	uint32_t y = ppu->scanline;
 
-	// if(x >= 256 || y >= 240) {
-	// 	return;
-	// }
-
 	uint32_t bit = 0x8000 >> ppu->fine_x;
 
 	if(ppu->reg_mask & 0x08) {
@@ -338,7 +270,18 @@ static void ppu_tick(struct nes_state *state) {
 	}
 
 	if(rendering && ((dot >= 2 && dot <= 257) || (dot >= 322 && dot <= 337))) {
-		ppu_sprite_shift(state);
+
+		if(ppu->reg_mask & 0x10) {
+			for(uint32_t i = 0; i < ppu->sprite_count; i++) {
+				if(ppu->sprite_positions[i] > 0) {
+					ppu->sprite_positions[i]--;
+				} else {
+					ppu->sprite_shift_lo[i] <<= 1;
+					ppu->sprite_shift_hi[i] <<= 1;
+				}
+			}
+		}
+
 		ppu->bg_shift_pattern_low <<= 1;
 		ppu->bg_shift_pattern_high <<= 1;
 		ppu->bg_shift_attrib_low <<= 1;
@@ -350,12 +293,12 @@ static void ppu_tick(struct nes_state *state) {
 			switch(dot % 8) {
 				case 1: {
 					uint32_t nt_addr = 0x2000 | (ppu->vram_addr & 0x0fff);
-					ppu->bg_next_tile_id = ppu_ciram_read(state, nt_addr);
+					ppu->bg_next_tile_id = state->mapper.ciram_read(state, nt_addr);
 					break;
 				}
 				case 3: {
 					uint32_t attr_addr = 0x23c0 | (ppu->vram_addr & 0x0c00) | ((ppu->vram_addr >> 4) & 0x38) | ((ppu->vram_addr >> 2) & 0x07);
-					uint8_t attr = ppu_ciram_read(state, attr_addr);
+					uint8_t attr = state->mapper.ciram_read(state, attr_addr & 0x0fff);
 					uint8_t shift = ((ppu->vram_addr >> 4) & 4) | (ppu->vram_addr & 2);
 					ppu->bg_next_tile_attrib = (attr >> shift) & 3;
 					break;
@@ -365,7 +308,7 @@ static void ppu_tick(struct nes_state *state) {
 					uint32_t tile = ppu->bg_next_tile_id;
 					uint32_t fine_y = (ppu->vram_addr >> 12) & 7;
 					uint32_t addr_lsb = (base + tile * 16 + fine_y) & 0x1fff;
-					ppu->bg_next_tile_lsb = state->chrrom[addr_lsb];
+					ppu->bg_next_tile_lsb = state->mapper.chr_read(state, addr_lsb);
 					break;
 				}
 				case 7: {
@@ -373,7 +316,7 @@ static void ppu_tick(struct nes_state *state) {
 					uint32_t tile = ppu->bg_next_tile_id;
 					uint32_t fine_y = (ppu->vram_addr >> 12) & 7;
 					uint32_t addr_msb = (base + tile * 16 + fine_y + 8) & 0x1fff;
-					ppu->bg_next_tile_msb = state->chrrom[addr_msb];
+					ppu->bg_next_tile_msb =  state->mapper.chr_read(state, addr_msb);
 					break;
 				}
 				case 0: {
@@ -419,7 +362,7 @@ static void ppu_tick(struct nes_state *state) {
 				ppu->vram_addr = (ppu->vram_addr & ~0x041f) | (ppu->temp_addr & 0x041f);
 			}
 
-			if(scanline == 261 && dot >= 280 && dot <= 304) {
+			if(scanline == 261 && dot == 304) { //>= 280 && dot <= 304) {
 				ppu->vram_addr = (ppu->vram_addr & ~0x7be0) | (ppu->temp_addr & 0x7be0);
 			}
 
@@ -479,6 +422,9 @@ static void ppu_dma_4014(struct nes_state *state, uint8_t page) {
 
 		state->cycles++;
 		ppu_tick(state); ppu_tick(state); ppu_tick(state);
-		ppu_write_2004(state, value);
+		// ppu_write_2004(state, value);
+		ppu_write(state, 4, value);
 	}
-}
\ No newline at end of file
+}
+
+