From d5a52cc491a222f1b7d33fa6789bed617ec6638b Mon Sep 17 00:00:00 2001 From: Hannes Schulze Date: Sat, 18 Jan 2025 00:05:53 +0100 Subject: cpu: bugfixes --- src/nes/mapper.cc | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'src/nes/mapper.cc') diff --git a/src/nes/mapper.cc b/src/nes/mapper.cc index a540dbf..a451e3a 100644 --- a/src/nes/mapper.cc +++ b/src/nes/mapper.cc @@ -27,9 +27,13 @@ namespace nes auto mapper::nrom_read(address const addr) -> std::uint8_t { + if (addr <= address{ 0x5FFF }) + { + return 0x0; + } if (addr <= address{ 0x7FFF }) { - return cartridge_.get_ram()[addr.get_absolute() % 0x2000]; + return cartridge_.get_ram()[addr.get_absolute() - 0x6000]; } if (addr <= address{ 0xBFFF }) { @@ -52,9 +56,13 @@ namespace nes auto mapper::nrom_write(address const addr, std::uint8_t const value) -> void { + if (addr <= address{ 0x5FFF }) + { + return; + } if (addr <= address{ 0x7FFF }) { - cartridge_.get_ram_mut()[addr.get_absolute() % 0x2000] = value; + cartridge_.get_ram_mut()[addr.get_absolute() - 0x6000] = value; } } -- cgit v1.3.1