diff options
Diffstat (limited to 'src/emu/bus/vectrex/rom.c')
-rw-r--r-- | src/emu/bus/vectrex/rom.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/src/emu/bus/vectrex/rom.c b/src/emu/bus/vectrex/rom.c new file mode 100644 index 00000000000..ceaa76c24c7 --- /dev/null +++ b/src/emu/bus/vectrex/rom.c @@ -0,0 +1,86 @@ +/*********************************************************************************************************** + + + GCE Vectrex cart emulation + + TODO: + - better understand how much SRAM is expected to be present by the homebrew using + this cart type and use a RAM array instead of the ROM region for writes + + ***********************************************************************************************************/ + + +#include "emu.h" +#include "rom.h" + + +//------------------------------------------------- +// vectrex_rom_device - constructor +//------------------------------------------------- + +const device_type VECTREX_ROM_STD = &device_creator<vectrex_rom_device>; +const device_type VECTREX_ROM_64K = &device_creator<vectrex_rom64k_device>; +const device_type VECTREX_ROM_SRAM = &device_creator<vectrex_sram_device>; + + +vectrex_rom_device::vectrex_rom_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, const char *shortname, const char *source) + : device_t(mconfig, type, name, tag, owner, clock, shortname, source), + device_vectrex_cart_interface(mconfig, *this) +{ +} + +vectrex_rom_device::vectrex_rom_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) + : device_t(mconfig, VECTREX_ROM_STD, "Vectrex Standard Carts", tag, owner, clock, "vectrex_rom", __FILE__), + device_vectrex_cart_interface(mconfig, *this) +{ +} + +vectrex_rom64k_device::vectrex_rom64k_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) + : vectrex_rom_device(mconfig, VECTREX_ROM_64K, "Vectrex Carts w/ Bankswitch", tag, owner, clock, "vectrex_64k", __FILE__) +{ +} + +vectrex_sram_device::vectrex_sram_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) + : vectrex_rom_device(mconfig, VECTREX_ROM_SRAM, "Vectrex Carts w/ SRAM", tag, owner, clock, "vectrex_sram", __FILE__) +{ +} + + +void vectrex_rom64k_device::device_start() +{ + save_item(NAME(m_bank)); +} + +void vectrex_rom64k_device::device_reset() +{ + m_bank = 0; +} + + +/*------------------------------------------------- + mapper specific handlers + -------------------------------------------------*/ + +READ8_MEMBER(vectrex_rom_device::read_rom) +{ + if (offset < m_rom_size) + return m_rom[offset]; + else + return 0xff; +} + + +READ8_MEMBER(vectrex_rom64k_device::read_rom) +{ + return m_rom[(offset + m_bank * 0x8000) & (m_rom_size - 1)]; +} + +WRITE8_MEMBER(vectrex_rom64k_device::write_bank) +{ + m_bank = data >> 6; +} + +WRITE8_MEMBER(vectrex_sram_device::write_ram) +{ + m_rom[offset & (m_rom_size - 1)] = data; +} |