cleanup and rewrite of ppu_registers.c

1 files changed, 41 insertions, 0 deletions

diff --git a/mappers/mapper_002_2.c b/mappers/mapper_002_2.c
new file mode 100644
index 0000000..079fb0b
--- /dev/null
+++ b/mappers/mapper_002_2.c
@@ -0,0 +1,41 @@
+
+
+static uint8_t mapper_002_2_prg_read(struct nes_state *state, uint32_t addr) {
+	struct mapper_002_2 *mapper = (struct mapper_002_2 *)&state->map;
+
+	if(addr >= 0x8000 && addr < 0xc000) {
+		return mapper->prg_bank0[addr & 0x3fff];
+
+	} else if(addr >= 0xc000) {
+		return mapper->prg_bank1[addr & 0x3fff];
+	}
+	return 0;
+}
+
+static void mapper_002_2_prg_write(struct nes_state *state, uint32_t addr, uint8_t value) {
+	struct mapper_002_2 *mapper = (struct mapper_002_2 *)&state->map;
+
+	if(addr >= 0x8000) {
+		mapper->prg_bank0 = state->prg_rom + ((value & 0x0f) * 0x4000);
+	}
+}
+
+static uint8_t mapper_002_2_chr_read(struct nes_state *state, uint32_t addr) {
+	return state->chr_ram[addr];
+}
+
+static void mapper_002_2_chr_write(struct nes_state *state, uint32_t addr, uint8_t value) {
+	state->chr_ram[addr] = value;
+}
+
+static void mapper_002_2_init(struct nes_state *state) {
+	struct mapper_002_2 *mapper = (struct mapper_002_2 *)&state->map;
+
+	mapper->prg_bank0 = state->prg_rom;
+	mapper->prg_bank1 = state->prg_rom + state->ines.prg_size - 0x4000;
+
+	state->mapper.prg_read	= mapper_002_2_prg_read;
+	state->mapper.prg_write	= mapper_002_2_prg_write;
+	state->mapper.chr_read	= mapper_002_2_chr_read;
+	state->mapper.chr_write	= mapper_002_2_chr_write;
+}