// license:BSD-3-Clause // copyright-holders:Sandro Ronco /*************************************************************************** K233 16K Shared RAM ***************************************************************************/ #include "emu.h" #include "k233.h" /*************************************************************************** IMPLEMENTATION ***************************************************************************/ //************************************************************************** // GLOBAL VARIABLES //************************************************************************** DEFINE_DEVICE_TYPE(DMV_K233, dmv_k233_device, "dmv_k233", "K233 16K Shared RAM") //************************************************************************** // LIVE DEVICE //************************************************************************** //------------------------------------------------- // dmv_k233_device - constructor //------------------------------------------------- dmv_k233_device::dmv_k233_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : device_t(mconfig, DMV_K233, tag, owner, clock) , device_dmvslot_interface(mconfig, *this) , m_enabled(false) , m_ram(nullptr) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void dmv_k233_device::device_start() { m_ram = machine().memory().region_alloc( "sharedram", 0x4000, 1, ENDIANNESS_LITTLE )->base(); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void dmv_k233_device::device_reset() { m_enabled = false; } void dmv_k233_device::io_write(int ifsel, offs_t offset, uint8_t data) { if (ifsel == 1) m_enabled = !m_enabled; } //------------------------------------------------- // read //------------------------------------------------- bool dmv_k233_device::read(offs_t offset, uint8_t &data) { if (m_enabled && offset >= 0xc000 && offset < 0x10000) { data = m_ram[offset & 0x3fff]; return true; } return false; } //------------------------------------------------- // write //------------------------------------------------- bool dmv_k233_device::write(offs_t offset, uint8_t data) { if (m_enabled && offset >= 0xc000 && offset < 0x10000) { m_ram[offset & 0x3fff] = data; return true; } return false; }