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Diffstat (limited to 'src/emu/bus/comx35/ram.c')
-rw-r--r-- | src/emu/bus/comx35/ram.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/src/emu/bus/comx35/ram.c b/src/emu/bus/comx35/ram.c new file mode 100644 index 00000000000..1bec0a5343b --- /dev/null +++ b/src/emu/bus/comx35/ram.c @@ -0,0 +1,106 @@ +// license:BSD-3-Clause +// copyright-holders:Curt Coder +/********************************************************************** + + COMX-35 RAM Card emulation + + Copyright MESS Team. + Visit http://mamedev.org for licensing and usage restrictions. + +**********************************************************************/ + +#include "ram.h" + + + +//************************************************************************** +// MACROS/CONSTANTS +//************************************************************************** + +#define RAM_SIZE 0x8000 + + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +const device_type COMX_RAM = &device_creator<comx_ram_device>; + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// comx_ram_device - constructor +//------------------------------------------------- + +comx_ram_device::comx_ram_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, COMX_RAM, "COMX-35 RAM Card", tag, owner, clock, "comx_ram", __FILE__), + device_comx_expansion_card_interface(mconfig, *this), + m_ram(*this, "ram") +{ +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void comx_ram_device::device_start() +{ + m_ram.allocate(RAM_SIZE); +} + + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void comx_ram_device::device_reset() +{ +} + + +//------------------------------------------------- +// comx_mrd_r - memory read +//------------------------------------------------- + +UINT8 comx_ram_device::comx_mrd_r(address_space &space, offs_t offset, int *extrom) +{ + UINT8 data = 0; + + if (offset >= 0xc000 && offset < 0xd000) + { + data = m_ram[(m_bank << 12) | (offset & 0xfff)]; + } + + return data; +} + + +//------------------------------------------------- +// comx_mwr_w - memory write +//------------------------------------------------- + +void comx_ram_device::comx_mwr_w(address_space &space, offs_t offset, UINT8 data) +{ + if (offset >= 0xc000 && offset < 0xd000) + { + m_ram[(m_bank << 12) | (offset & 0xfff)] = data; + } +} + + +//------------------------------------------------- +// comx_io_w - I/O write +//------------------------------------------------- + +void comx_ram_device::comx_io_w(address_space &space, offs_t offset, UINT8 data) +{ + if (offset == 1) + { + m_bank = (data >> 4) & 0x03; + } +} |