first mknes commit

1 files changed, 27 insertions, 0 deletions

diff --git a/mapper_nrom.c b/mapper_nrom.c
new file mode 100644
index 0000000..425db31
--- /dev/null
+++ b/mapper_nrom.c
@@ -0,0 +1,27 @@
+
+
+static void mapper_nrom_init(struct state *state) {
+	// Nothing to initialize for NROM
+}
+
+static uint8_t mapper_nrom_read(struct state *state, uint16_t addr) {
+	uint32_t prg_size = state->ines.prg_size;
+
+	if(state->ines.prg_size == 16384) {
+		return state->rom[addr & 0x3fff];
+	} else {
+		return state->rom[addr - 0x8000];
+	}
+	return 0;
+}
+
+static void mapper_nrom_write(struct state *state, uint16_t addr, uint8_t value) {
+	(void)state;
+	(void)addr;
+	(void)value;
+}
+
+static void mapper_nrom_tick(struct state *state) {
+	(void)state;
+}
+