diff options
Diffstat (limited to 'src/devices/bus/odyssey2/ktaa.cpp')
-rw-r--r-- | src/devices/bus/odyssey2/ktaa.cpp | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/src/devices/bus/odyssey2/ktaa.cpp b/src/devices/bus/odyssey2/ktaa.cpp index d968a35ed24..b9cf38bbf95 100644 --- a/src/devices/bus/odyssey2/ktaa.cpp +++ b/src/devices/bus/odyssey2/ktaa.cpp @@ -30,11 +30,25 @@ void o2_ktaa_device::device_start() void o2_ktaa_device::cart_init() { - u32 size = m_rom_size; - if (size != 0xc00 && size != 0xc00*2 && size != 0xc00*4) - fatalerror("o2_ktaa_device: ROM size must be multiple of 3KB\n"); - - m_bank_mask = (size / 0xc00) - 1; + bool err = false; + + if (m_rom_size & (m_rom_size - 1)) + { + // freely released binary file is 12KB + err = m_rom_size != 0xc00 && m_rom_size != 0xc00*2 && m_rom_size != 0xc00*4; + m_page_size = 0xc00; + } + else + { + // actual ROM is 16KB(27C128), first 1KB of each 4KB block is empty + err = m_rom_size < 0x1000; + m_page_size = 0x1000; + } + + if (err) + fatalerror("o2_ktaa_device: ROM size must be multiple of 3KB or 4KB\n"); + + m_bank_mask = (m_rom_size / m_page_size) - 1; } @@ -44,10 +58,6 @@ void o2_ktaa_device::cart_init() u8 o2_ktaa_device::read_rom04(offs_t offset) { - return m_rom[offset + m_bank * 0xc00]; -} - -u8 o2_ktaa_device::read_rom0c(offs_t offset) -{ - return m_rom[offset + 0x800 + m_bank * 0xc00]; + offset += m_page_size - 0xc00; + return m_rom[offset + m_bank * m_page_size]; } |