diff options
Diffstat (limited to 'src/devices/bus/aquarius/supercart.cpp')
-rw-r--r-- | src/devices/bus/aquarius/supercart.cpp | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/src/devices/bus/aquarius/supercart.cpp b/src/devices/bus/aquarius/supercart.cpp new file mode 100644 index 00000000000..2bc2ad82fd8 --- /dev/null +++ b/src/devices/bus/aquarius/supercart.cpp @@ -0,0 +1,101 @@ +// license:BSD-3-Clause +// copyright-holders:Nigel Barnes +/*************************************************************************** + + Aquarius SuperCart Cartridge + +***************************************************************************/ + +#include "emu.h" +#include "supercart.h" + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +DEFINE_DEVICE_TYPE(AQUARIUS_SC1, aquarius_sc1_device, "aquarius_sc1", "Aquarius SuperCart I Cartridge") + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// aquarius_sc1_device - constructor +//------------------------------------------------- + +aquarius_sc1_device::aquarius_sc1_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : device_t(mconfig, AQUARIUS_SC1, tag, owner, clock) + , device_aquarius_cartridge_interface(mconfig, *this) + , m_bank(0) + , m_mode(0) +{ +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void aquarius_sc1_device::device_start() +{ + save_item(NAME(m_bank)); + save_item(NAME(m_mode)); +} + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void aquarius_sc1_device::device_reset() +{ + static const unsigned char SC08_HEADER[16] = { 0x53, 0x43, 0x30, 0x38, 0x4b, 0x9c, 0xb5, 0xb0, 0xa8, 0x6c, 0xac, 0x64, 0xcc, 0xa8, 0x06, 0x70 }; + static const unsigned char SC16_HEADER[16] = { 0x53, 0x43, 0x31, 0x36, 0x4b, 0x9c, 0xb5, 0xb0, 0xa8, 0x6c, 0xac, 0x64, 0xcc, 0xa8, 0x08, 0x70 }; + + uint8_t* header = get_rom_base() + get_rom_size() - 0x2000; + + // select bank switching mode + if (!memcmp(header, SC08_HEADER, 16)) + m_mode = 0; + else if (!memcmp(header, SC16_HEADER, 16)) + m_mode = 1; + else + fatalerror("Invalid SuperCart mode header\n"); +} + + +//************************************************************************** +// IMPLEMENTATION +//************************************************************************** + +uint8_t aquarius_sc1_device::mreq_ce_r(offs_t offset) +{ + switch (m_mode) + { + case 0: // 8K Mode + if (offset & 0x2000) + { + offset |= get_rom_size() - 0x2000; + } + else + { + offset |= m_bank << 13; + } + break; + + case 1: // 16K Mode + offset |= (m_bank & 0x7e) << 13; + break; + } + + return get_rom_base()[offset & (get_rom_size() - 1)]; +} + +void aquarius_sc1_device::mreq_ce_w(offs_t offset, uint8_t data) +{ + if (offset & 0x2000) + { + m_bank = data & 0x7f; + } +} |