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Diffstat (limited to 'src/devices/bus/c64/silverrock.cpp')
-rw-r--r-- | src/devices/bus/c64/silverrock.cpp | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/src/devices/bus/c64/silverrock.cpp b/src/devices/bus/c64/silverrock.cpp new file mode 100644 index 00000000000..9e9ce421a6c --- /dev/null +++ b/src/devices/bus/c64/silverrock.cpp @@ -0,0 +1,132 @@ +// 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 "silverrock.h" + + + +//************************************************************************** +// MACROS/CONSTANTS +//************************************************************************** + +#define UNSCRAMBLE_ADDRESS(_offset) \ + BITSWAP16(_offset,15,14,13,12,1,0,2,3,11,10,9,8,7,6,5,4) + +#define UNSCRAMBLE_DATA(_data) \ + BITSWAP8(_data,7,6,5,4,0,1,2,3) + + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +const device_type C64_SILVERROCK = &device_creator<c64_silverrock_cartridge_device>; + + + +//************************************************************************** +// 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 clock) : + device_t(mconfig, C64_SILVERROCK, "C64 SilverRock cartridge", tag, owner, clock, "c64_silverrock", __FILE__), + device_c64_expansion_card_interface(mconfig, *this) +{ +} + + +//------------------------------------------------- +// 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 c64_silverrock_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 (!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(address_space &space, offs_t offset, UINT8 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); + } +} |