diff options
Diffstat (limited to 'src/devices/bus/c64/neoram.c')
-rw-r--r-- | src/devices/bus/c64/neoram.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/src/devices/bus/c64/neoram.c b/src/devices/bus/c64/neoram.c new file mode 100644 index 00000000000..2b885c86f55 --- /dev/null +++ b/src/devices/bus/c64/neoram.c @@ -0,0 +1,99 @@ +// license:BSD-3-Clause +// copyright-holders:Curt Coder +/********************************************************************** + + NeoRAM cartridge emulation + +**********************************************************************/ + +#include "neoram.h" + + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +const device_type C64_NEORAM = &device_creator<c64_neoram_cartridge_device>; + + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// c64_neoram_cartridge_device - constructor +//------------------------------------------------- + +c64_neoram_cartridge_device::c64_neoram_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, C64_NEORAM, "C64 NeoRAM cartridge", tag, owner, clock, "c64_neoram", __FILE__), + device_c64_expansion_card_interface(mconfig, *this), + device_nvram_interface(mconfig, *this) +{ +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void c64_neoram_cartridge_device::device_start() +{ + // allocate memory + m_nvram.allocate(0x200000); + + // state saving + save_item(NAME(m_bank)); +} + + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void c64_neoram_cartridge_device::device_reset() +{ + m_bank = 0; +} + + +//------------------------------------------------- +// c64_cd_r - cartridge data read +//------------------------------------------------- + +UINT8 c64_neoram_cartridge_device::c64_cd_r(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2) +{ + if (!io1) + { + offs_t addr = (m_bank << 8) | (offset & 0xff); + data = m_nvram[addr]; + } + + return data; +} + + +//------------------------------------------------- +// c64_cd_w - cartridge data write +//------------------------------------------------- + +void c64_neoram_cartridge_device::c64_cd_w(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2) +{ + if (!io1) + { + offs_t addr = (m_bank << 8) | (offset & 0xff); + m_nvram[addr] = data; + } + else if (!io2) + { + if (BIT(offset, 0)) + { + m_bank = ((data & 0x7f) << 6) | (m_bank & 0x3f); + } + else + { + m_bank = (m_bank & 0x1fc0) | (data & 0x3f); + } + } +} |