From f1bd6a7d2f4ffe3e5263e0254bcf7522ab381264 Mon Sep 17 00:00:00 2001 From: Peter Fors Date: Sat, 5 Apr 2025 08:58:12 +0200 Subject: transform to switch case for ppu_tick() --- mapper_0042.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 mapper_0042.c (limited to 'mapper_0042.c') diff --git a/mapper_0042.c b/mapper_0042.c new file mode 100644 index 0000000..4cf4c86 --- /dev/null +++ b/mapper_0042.c @@ -0,0 +1,30 @@ + +static void mapper_0042_init(struct nes_state *state) { + state->map.m0042.prg_offset = 0; + state->map.m0042.chr_offset = 0; +} + +static uint8_t mapper_0042_prg_read(struct nes_state *state, uint32_t addr) { + if(addr >= 0x8000) { + uint32_t base = state->map.m0042.prg_offset; + return state->prg_rom[base + (addr - 0x8000)]; + } + return 0; +} + +static void mapper_0042_prg_write(struct nes_state *state, uint32_t addr, uint8_t value) { + if(addr >= 0x8000) { + uint32_t prg_bank = (value >> 4) & 3; + uint32_t chr_bank = (value >> 0) & 3; + + state->map.m0042.prg_offset = prg_bank * 0x8000; + state->map.m0042.chr_offset = chr_bank * 0x2000; + } +} + +static uint8_t mapper_0042_chr_read(struct nes_state *state, uint32_t addr) { + return state->chr_rom[state->map.m0042.chr_offset + addr]; +} + +static void mapper_0042_chr_write(struct nes_state *state, uint32_t addr, uint8_t value) { +} -- cgit v1.2.3