// license:BSD-3-Clause // copyright-holders:Curt Coder /********************************************************************** SilverRock Productions cartridge emulation **********************************************************************/ /* PCB Layout ---------- e9048 |=============| |=| LS00 | |=| LS273| |=| | |=| | |=| ROM | |=| | |=| | |=| | |=============| ROM - Atmel AT27C010-25PC 128Kx8 OTP EPROM "HUGO 2012" */ #include "emu.h" #include "silverrock.h" //************************************************************************** // MACROS/CONSTANTS //************************************************************************** #define UNSCRAMBLE_ADDRESS(_offset) \ bitswap<16>(_offset,15,14,13,12,1,0,2,3,11,10,9,8,7,6,5,4) #define UNSCRAMBLE_DATA(_data) \ bitswap<8>(_data,7,6,5,4,0,1,2,3) //************************************************************************** // DEVICE DEFINITIONS //************************************************************************** DEFINE_DEVICE_TYPE(C64_SILVERROCK, c64_silverrock_cartridge_device, "c64_silverrock", "C64 SilverRock cartridge") //************************************************************************** // LIVE DEVICE //************************************************************************** //------------------------------------------------- // c64_silverrock_cartridge_device - constructor //------------------------------------------------- c64_silverrock_cartridge_device::c64_silverrock_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : device_t(mconfig, C64_SILVERROCK, tag, owner, clock), device_c64_expansion_card_interface(mconfig, *this), m_bank(0) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void c64_silverrock_cartridge_device::device_start() { // state saving save_item(NAME(m_bank)); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void c64_silverrock_cartridge_device::device_reset() { m_bank = 0; } //------------------------------------------------- // c64_cd_r - cartridge data read //------------------------------------------------- uint8_t c64_silverrock_cartridge_device::c64_cd_r(offs_t offset, uint8_t data, int sphi2, int ba, int roml, int romh, int io1, int io2) { if (!roml) { offs_t addr = (m_bank << 13) | (offset & 0x1fff); addr = (addr & 0x10000) | UNSCRAMBLE_ADDRESS(addr); data = UNSCRAMBLE_DATA(m_roml[addr]); } return data; } //------------------------------------------------- // c64_cd_w - cartridge data write //------------------------------------------------- void c64_silverrock_cartridge_device::c64_cd_w(offs_t offset, uint8_t data, int sphi2, int ba, int roml, int romh, int io1, int io2) { if (!io1) { /* bit description 0 1 2 3 4 A14 5 A15 6 A16 7 A13 */ m_bank = ((data >> 3) & 0x0e) | BIT(data, 7); } }