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Diffstat (limited to 'src/mess/machine/c64/structured_basic.c')
-rw-r--r-- | src/mess/machine/c64/structured_basic.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/src/mess/machine/c64/structured_basic.c b/src/mess/machine/c64/structured_basic.c new file mode 100644 index 00000000000..12232b627ac --- /dev/null +++ b/src/mess/machine/c64/structured_basic.c @@ -0,0 +1,104 @@ +/********************************************************************** + + Structured Basic cartridge emulation + + Copyright MESS Team. + Visit http://mamedev.org for licensing and usage restrictions. + +**********************************************************************/ + +#include "structured_basic.h" + + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +const device_type C64_STRUCTURED_BASIC = &device_creator<c64_structured_basic_cartridge_device>; + + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// c64_structured_basic_cartridge_device - constructor +//------------------------------------------------- + +c64_structured_basic_cartridge_device::c64_structured_basic_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, C64_STRUCTURED_BASIC, "C64 Structured Basic cartridge", tag, owner, clock, "c64_structured_basic", __FILE__), + device_c64_expansion_card_interface(mconfig, *this) +{ +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void c64_structured_basic_cartridge_device::device_start() +{ + // state saving + save_item(NAME(m_bank)); +} + + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void c64_structured_basic_cartridge_device::device_reset() +{ + m_exrom = 0; + + m_bank = 0; +} + + +//------------------------------------------------- +// c64_cd_r - cartridge data read +//------------------------------------------------- + +UINT8 c64_structured_basic_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); + + data = m_roml[addr]; + } + + return data; +} + + +//------------------------------------------------- +// c64_cd_w - cartridge data write +//------------------------------------------------- + +void c64_structured_basic_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) + { + switch (data & 0x03) + { + case 0: + case 1: + m_exrom = 0; + m_bank = 0; + break; + + case 2: + m_exrom = 0; + m_bank = 1; + break; + + case 3: + m_exrom = 1; + m_bank = 0; + break; + } + } +} |