cleanup and rewrite of ppu_registers.c

1 files changed, 27 insertions, 0 deletions

diff --git a/mappers/mapper_003_0.c b/mappers/mapper_003_0.c
new file mode 100644
index 0000000..5ccfb53
--- /dev/null
+++ b/mappers/mapper_003_0.c
@@ -0,0 +1,27 @@
+
+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;
+}