// license:BSD-3-Clause // copyright-holders:Curt Coder /********************************************************************** COMX-35 RAM Card emulation **********************************************************************/ #include "emu.h" #include "ram.h" //************************************************************************** // MACROS/CONSTANTS //************************************************************************** #define RAM_SIZE 0x8000 //************************************************************************** // DEVICE DEFINITIONS //************************************************************************** DEFINE_DEVICE_TYPE(COMX_RAM, comx_ram_device, "comx_ram", "COMX-35 RAM Card") //************************************************************************** // LIVE DEVICE //************************************************************************** //------------------------------------------------- // comx_ram_device - constructor //------------------------------------------------- comx_ram_device::comx_ram_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : device_t(mconfig, COMX_RAM, tag, owner, clock), device_comx_expansion_card_interface(mconfig, *this), m_ram(*this, "ram"), m_bank(0) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void comx_ram_device::device_start() { m_ram.allocate(RAM_SIZE); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void comx_ram_device::device_reset() { } //------------------------------------------------- // comx_mrd_r - memory read //------------------------------------------------- uint8_t comx_ram_device::comx_mrd_r(offs_t offset, int *extrom) { uint8_t data = 0; if (offset >= 0xc000 && offset < 0xd000) { data = m_ram[(m_bank << 12) | (offset & 0xfff)]; } return data; } //------------------------------------------------- // comx_mwr_w - memory write //------------------------------------------------- void comx_ram_device::comx_mwr_w(offs_t offset, uint8_t data) { if (offset >= 0xc000 && offset < 0xd000) { m_ram[(m_bank << 12) | (offset & 0xfff)] = data; } } //------------------------------------------------- // comx_io_w - I/O write //------------------------------------------------- void comx_ram_device::comx_io_w(offs_t offset, uint8_t data) { if (offset == 1) { m_bank = (data >> 4) & 0x03; } }