// license:BSD-3-Clause // copyright-holders:Fabio Priuli /*********************************************************************************************************** Generic ROM emulation (for carts and ROM sockets) This offers generic access to a ROM generic_rom_plain : returns 0xff when the system reads beyond the end of the ROM generic_rom_linear : maps linearly the ROM in the accessed area (i.e., read offset is masked with (ROM size - 1) ) generic_romram_plain : allows support for carts always containing ROM + RAM (e.g. X07) TODO: - possibly support linear mapping when non-power of 2 ROMs are mapped ***********************************************************************************************************/ #include "emu.h" #include "rom.h" //------------------------------------------------- // constructor //------------------------------------------------- DEFINE_DEVICE_TYPE(GENERIC_ROM_PLAIN, generic_rom_plain_device, "generic_rom_plain", "Generic ROM (plain mapping)") DEFINE_DEVICE_TYPE(GENERIC_ROM_LINEAR, generic_rom_linear_device, "generic_rom_linear", "Generic ROM (linear mapping)") DEFINE_DEVICE_TYPE(GENERIC_ROMRAM_PLAIN, generic_romram_plain_device, "generic_romram_plain", "Generic ROM + RAM (plain mapping)") generic_rom_device::generic_rom_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, const XTAL &clock) : device_t(mconfig, type, tag, owner, clock), device_generic_cart_interface(mconfig, *this) { } generic_rom_plain_device::generic_rom_plain_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, const XTAL &clock) : generic_rom_device(mconfig, type, tag, owner, clock) { } generic_rom_plain_device::generic_rom_plain_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock) : generic_rom_plain_device(mconfig, GENERIC_ROM_PLAIN, tag, owner, clock) { } generic_rom_linear_device::generic_rom_linear_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock) : generic_rom_device(mconfig, GENERIC_ROM_LINEAR, tag, owner, clock) { } generic_romram_plain_device::generic_romram_plain_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock) : generic_rom_plain_device(mconfig, GENERIC_ROMRAM_PLAIN, tag, owner, clock) { } /*------------------------------------------------- mapper specific handlers -------------------------------------------------*/ uint8_t generic_rom_plain_device::read_rom(offs_t offset) { if (offset < m_rom_size) return m_rom[offset]; else return 0xff; } uint16_t generic_rom_plain_device::read16_rom(offs_t offset, uint16_t mem_mask) { uint16_t *ROM = (uint16_t *)m_rom; if (offset < m_rom_size/2) return ROM[offset]; else return 0xffff; } uint32_t generic_rom_plain_device::read32_rom(offs_t offset, uint32_t mem_mask) { uint32_t *ROM = (uint32_t *)m_rom; if (offset < m_rom_size/4) return ROM[offset]; else return 0xffffffff; } uint8_t generic_rom_linear_device::read_rom(offs_t offset) { return m_rom[offset % m_rom_size]; } uint16_t generic_rom_linear_device::read16_rom(offs_t offset, uint16_t mem_mask) { uint16_t *ROM = (uint16_t *)m_rom; return ROM[offset % (m_rom_size/2)]; } uint32_t generic_rom_linear_device::read32_rom(offs_t offset, uint32_t mem_mask) { uint32_t *ROM = (uint32_t *)m_rom; return ROM[offset % (m_rom_size/4)]; } uint8_t generic_romram_plain_device::read_ram(offs_t offset) { if (offset < m_ram.size()) return m_ram[offset]; else return 0xff; } void generic_romram_plain_device::write_ram(offs_t offset, uint8_t data) { if (offset < m_ram.size()) m_ram[offset] = data; }