From 5808f00555c48e1cc1cc110af6a5cd73ddf13010 Mon Sep 17 00:00:00 2001 From: Peter Fors Date: Fri, 2 May 2025 23:15:47 +0200 Subject: cleanup and rewrite of ppu_registers.c --- mappers/mapper_003_0.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 mappers/mapper_003_0.c (limited to 'mappers/mapper_003_0.c') 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; +} -- cgit v1.2.3