cleanup and rewrite of memory_read()

10 files changed, 61 insertions, 163 deletions

diff --git a/.gitignore b/.gitignore
index 770f711..33cf98b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,6 @@ vertex_shader.h
 *.fm2
 fm2h.py
 gmon.out
+*.gcov
+*.gcno
+*.gcda
diff --git a/build.sh b/build.sh
index 02d50d3..de8ecc5 100755
--- a/build.sh
+++ b/build.sh
@@ -3,7 +3,7 @@
 # Set the project name here
 PROJECT_NAME="mknes"  # Change this for each new project
 
-CC=gcc-14
+CC=gcc
 
 # Base configuration common to all builds
 CFLAGS="-std=gnu11 -mtune=generic "
diff --git a/mappers/mapper.c b/mappers/mapper.c
index d63e2a0..099b6d7 100644
--- a/mappers/mapper.c
+++ b/mappers/mapper.c
@@ -24,7 +24,7 @@ static void mapper_default_tick(struct nes_state *state) { }
 
 #include "mapper_000_0.c"
 #include "mapper_002_2.c"
-#include "mapper_003_0.c"
+#include "mapper_003_2.c"
 #include "mapper_007_2.c"
 #include "mapper_011_0.c"
 #include "mapper_066_0.c"
@@ -34,7 +34,7 @@ static void mapper_default_tick(struct nes_state *state) { }
 static void (*mapper_table[4096])(struct nes_state *state) = {
 	[MAPPER_ID( 0, 0)] = mapper_000_0_init,
 	[MAPPER_ID( 2, 2)] = mapper_002_2_init,
-	[MAPPER_ID( 3, 0)] = mapper_003_0_init,
+	[MAPPER_ID( 3, 2)] = mapper_003_2_init,
 	[MAPPER_ID( 7, 2)] = mapper_007_2_init,
 	[MAPPER_ID(11, 0)] = mapper_011_0_init,
 	[MAPPER_ID(66, 0)] = mapper_011_0_init,
diff --git a/mappers/mapper.h b/mappers/mapper.h
index 0961370..863201b 100644
--- a/mappers/mapper.h
+++ b/mappers/mapper.h
@@ -1,7 +1,7 @@
 
 #include "mapper_000_0.h"
 #include "mapper_002_2.h"
-#include "mapper_003_0.h"
+#include "mapper_003_2.h"
 #include "mapper_007_2.h"
 #include "mapper_011_0.h"
 #include "mapper_066_0.h"
@@ -21,7 +21,7 @@ struct mapper_functions {
 union mapper_data {
 	struct mapper_000_0 m000_0;
 	struct mapper_002_2 m002_2;
-	struct mapper_003_0 m003_0;
+	struct mapper_003_2 m003_2;
 	struct mapper_007_2 m007_2;
 	struct mapper_011_0 m011_0;
 	struct mapper_066_0 m066_0;
diff --git a/mappers/mapper_003_0.c b/mappers/mapper_003_0.c
deleted file mode 100644
index 5ccfb53..0000000
--- a/mappers/mapper_003_0.c
+++ /dev/null
@@ -1,27 +0,0 @@
-
-static uint8_t mapper_003_0_prg_read(struct nes_state *state, uint32_t addr) {
-	return state->prg_rom[addr & 0x7fff];
-}
-
-static void mapper_003_0_prg_write(struct nes_state *state, uint32_t addr, uint8_t value) {
-	struct mapper_003_0 *mapper = (struct mapper_003_0 *)&state->map;
-
-	if(addr >= 0x8000) {
-		mapper->chr_ptr = state->chr_rom + (value & 3) * 0x2000;
-	}
-}
-
-static uint8_t mapper_003_0_chr_read(struct nes_state *state, uint32_t addr) {
-	struct mapper_003_0 *mapper = (struct mapper_003_0 *)&state->map;
-	return mapper->chr_ptr[addr];
-}
-
-static void mapper_003_0_init(struct nes_state *state) {
-	struct mapper_003_0 *mapper = (struct mapper_003_0 *)&state->map;
-
-	mapper->chr_ptr = state->chr_rom;
-
-	state->mapper.prg_read	= mapper_003_0_prg_read;
-	state->mapper.prg_write	= mapper_003_0_prg_write;
-	state->mapper.chr_read	= mapper_003_0_chr_read;
-}
diff --git a/mappers/mapper_003_0.h b/mappers/mapper_003_0.h
deleted file mode 100644
index f03b106..0000000
--- a/mappers/mapper_003_0.h
+++ /dev/null
@@ -1,4 +0,0 @@
-
-struct mapper_003_0 {
-	uint8_t *chr_ptr;
-} __attribute__((packed, aligned(64)));
diff --git a/memory.c b/memory.c
index 74b0a0f..6e0c6df 100644
--- a/memory.c
+++ b/memory.c
@@ -7,10 +7,27 @@ static uint8_t memory_read(struct nes_state *restrict state, uint32_t offset) {
 	ppu_tick(state);
 	// apu_tick(state);
 
-	if(LIKELY(offset < 0x2000)) {
+	if(LIKELY(offset >= 0x6000)) {	// MOST
+		return state->mapper.prg_read(state, offset);
+
+	} else if(LIKELY(offset < 0x2000)) {	// SECOND
 		return state->ram[offset & 0x07ff];
 
-	} else if(offset < 0x4000) {
+	} else if(offset < 0x4000) {	// THIRD
+		return ppu_read(state, offset);
+
+	} else if(offset == 0x4016 || offset == 0x4017) {
+		uint32_t index = offset & 1;
+		uint8_t value = (state->ppu.input_latch[index] >> state->ppu.input_bit[index]) & 1;
+		state->ppu.input_bit[index]++;
+		return value | 0x40;	// Bit 6 open bus high, bit 7 low
+	}
+
+#if 0
+	if(LIKELY(offset < 0x2000)) {	// SECOND
+		return state->ram[offset & 0x07ff];
+
+	} else if(offset < 0x4000) {	// THIRD
 		return ppu_read(state, offset);
 
 	} else if(offset == 0x4016 || offset == 0x4017) {
@@ -23,10 +40,11 @@ static uint8_t memory_read(struct nes_state *restrict state, uint32_t offset) {
 	// 	static uint32_t apuread = 0;
 	// 	// printf("%.5d apu\n", apuread++);
 
-	} else if(LIKELY(offset >= 0x6000)) {
+	} else if(LIKELY(offset >= 0x6000)) {	// MOST
 		return state->mapper.prg_read(state, offset);
 
 	}
+#endif
 	return 0;
 }
 
diff --git a/mknes.c b/mknes.c
index 2aff691..b5f05d3 100644
--- a/mknes.c
+++ b/mknes.c
@@ -206,7 +206,7 @@ int main(int argc, char **argv) {
 	// ines2_load(nstate, "data/0003/Flipull - An Exciting Cube Game (Japan) (En).zip");
 	// ines2_load(nstate, "data/0003/Friday the 13th (USA).zip");
 	// ines2_load(nstate, "data/0003/Ghostbusters (Japan).zip");
-	// ines2_load(nstate, "data/0003/Gradius (USA).zip");
+	ines2_load(nstate, "data/0003/Gradius (USA).zip");
 	// ines2_load(nstate, "data/0007/Battletoads (USA).zip");
 	// ines2_load(nstate, "data/0007/Beetlejuice (USA).zip");
 	// ines2_load(nstate, "data/0007/Cabal (USA).zip");
@@ -224,7 +224,7 @@ int main(int argc, char **argv) {
 	uint32_t hi = nstate->mapper.prg_read(nstate, 0xfffd);
 	nstate->cpu.pc = (hi << 8) | lo;
 
-#if 1
+#if 0
 	for(uint32_t i = 0; i < 0x5000; ++ i) {
 		while(!nstate->ppu.frame_ready) {
 			// PROFILE_NAMED("nes emulator");
diff --git a/ppu.c b/ppu.c
index 6b57085..fe54be5 100644
--- a/ppu.c
+++ b/ppu.c
@@ -192,6 +192,7 @@ static void ppu_tick(struct nes_state *state) {
 							if((ppu->vram_addr & 0x7000) != 0x7000) {
 								ppu->vram_addr += 0x1000;
 							} else {
+
 								ppu->vram_addr &= ~0x7000;
 								uint32_t y = (ppu->vram_addr & 0x03e0) >> 5;
 								if(y == 29) {
diff --git a/ppu_registers.c b/ppu_registers.c
index b426f17..f6bd515 100644
--- a/ppu_registers.c
+++ b/ppu_registers.c
@@ -4,22 +4,26 @@ static inline void ppu_write(struct nes_state *state, uint32_t offset, uint8_t v
 
 	uint32_t reg = offset & 0x7;
 
-	if(reg == 0) {
-		ppu->reg_ctrl = value;
-		ppu->temp_addr = (ppu->temp_addr & 0xf3ff) | ((value & 0x03) << 10);
-		// ppu->open_bus = value;
+	if(LIKELY(reg == 4)) {
+		ppu->oam[ppu->oam_addr++] = value;
+		ppu->open_bus = value;
+		return;
 
 	} else if(reg == 1) {
 		ppu->reg_mask = value;
-		// ppu->open_bus = value;
+		ppu->open_bus = value;
+		return;
+
+	} else if(reg == 0) {
+		ppu->reg_ctrl = value;
+		ppu->temp_addr = (ppu->temp_addr & 0xf3ff) | ((value & 0x03) << 10);
+		ppu->open_bus = value;
+		return;
 
 	} else if(reg == 3) {
 		ppu->oam_addr = value;
-		// ppu->open_bus = value;
-
-	} else if(reg == 4) {
-		ppu->oam[ppu->oam_addr++] = value;
-		// ppu->open_bus = value;
+		ppu->open_bus = value;
+		return;
 
 	} else if(reg == 5) {
 		if(ppu->write_latch == 0) {
@@ -30,7 +34,8 @@ static inline void ppu_write(struct nes_state *state, uint32_t offset, uint8_t v
 			ppu->temp_addr = (ppu->temp_addr & ~0x73e0) | ((value & 0x07) << 12) | ((value & 0xf8) << 2);
 			ppu->write_latch = 0;
 		}
-		// ppu->open_bus = value;
+		ppu->open_bus = value;
+		return;
 
 	} else if(reg == 6) {
 		if(ppu->write_latch == 0) {
@@ -41,11 +46,12 @@ static inline void ppu_write(struct nes_state *state, uint32_t offset, uint8_t v
 			ppu->vram_addr = ppu->temp_addr;
 			ppu->write_latch = 0;
 		}
-		// ppu->open_bus = value;
+		ppu->open_bus = value;
+		return;
 
 	} else if(reg == 7) {
 		uint32_t addr = ppu->vram_addr;
-		if(LIKELY(addr < 0x2000)) {
+		if(addr < 0x2000) {
 			state->mapper.chr_write(state, addr, value);
 
 		} else if(LIKELY(addr < 0x3f00)) {
@@ -59,78 +65,9 @@ static inline void ppu_write(struct nes_state *state, uint32_t offset, uint8_t v
 			ppu->palette[pal_addr] = value;
 		}
 		ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
-		// ppu->open_bus = value;
+		ppu->open_bus = value;
+		return;
 	}
-
-	ppu->open_bus = value;
-
-#if 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;
-			ppu->open_bus = value;
-		} break;
-
-		case 4: {		// 2004
-			ppu->oam[ppu->oam_addr++] = value;
-			ppu->open_bus = value;
-		} 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;
-
-		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;
-			if(LIKELY(addr < 0x2000)) {
-				state->mapper.chr_write(state, addr, value);
-
-			} else if(LIKELY(addr < 0x3f00)) {
-				state->mapper.ciram_write(state, addr, value);
-
-			} else if(addr < 0x4000) {
-				uint32_t pal_addr = addr & 0x1f;
-				if((pal_addr & 3) == 0) {
-					pal_addr &= ~0x10;
-				}
-				ppu->palette[pal_addr] = value;
-			}
-			ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
-			ppu->open_bus = value;
-		} break;
-	}
-#endif
 }
 
 __attribute__((always_inline, hot))
@@ -140,13 +77,17 @@ static inline uint8_t ppu_read(struct nes_state *state, uint32_t offset) {
 
 	uint32_t reg = offset & 0x7;
 
-	if(reg == 2) {
+	if(LIKELY(reg == 2)) {
 		result = ppu->reg_status;
 		ppu->reg_status &= ~0x80;
 		ppu->write_latch = 0;
+		ppu->open_bus = result;
+		return result;
 
-	} else if(reg == 4) {
+	} else if(LIKELY(reg == 4)) {
 		result = ppu->oam[ppu->oam_addr];
+		ppu->open_bus = result;
+		return result;
 
 	} else if(reg == 7) {
 		uint32_t addr = ppu->vram_addr;
@@ -168,45 +109,11 @@ static inline uint8_t ppu_read(struct nes_state *state, uint32_t offset) {
 		}
 
 		ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
-	}
-
-#if 0
-	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;
-
-			if(LIKELY(addr < 0x2000)) {
-				result = ppu->vram_read_buffer;
-				ppu->vram_read_buffer =  state->mapper.chr_read(state, addr);
-
-			} else if(LIKELY(addr < 0x3f00)) {
-				result = ppu->vram_read_buffer;
-				ppu->vram_read_buffer = 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];
-			}
+		ppu->open_bus = result;
+		return result;
 
-			ppu->vram_addr += (ppu->reg_ctrl & 0x04) ? 32 : 1;
-		} break;
 	}
-# endif
 
-	ppu->open_bus = result;
 	return result;
 }