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Diffstat (limited to 'src/devices/bus/dmv/k233.cpp')
-rw-r--r-- | src/devices/bus/dmv/k233.cpp | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/src/devices/bus/dmv/k233.cpp b/src/devices/bus/dmv/k233.cpp new file mode 100644 index 00000000000..859b8b7f8f8 --- /dev/null +++ b/src/devices/bus/dmv/k233.cpp @@ -0,0 +1,89 @@ +// license:BSD-3-Clause +// copyright-holders:Sandro Ronco +/*************************************************************************** + + K233 16K Shared RAM + +***************************************************************************/ + +#include "emu.h" +#include "k233.h" + + +/*************************************************************************** + IMPLEMENTATION +***************************************************************************/ + +//************************************************************************** +// GLOBAL VARIABLES +//************************************************************************** + +const device_type DMV_K233 = &device_creator<dmv_k233_device>; + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// dmv_k233_device - constructor +//------------------------------------------------- + +dmv_k233_device::dmv_k233_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) + : device_t(mconfig, DMV_K233, "K233 16K Shared RAM", tag, owner, clock, "dmv_k233", __FILE__), + device_dmvslot_interface( mconfig, *this ) +{ +} + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void dmv_k233_device::device_start() +{ + m_ram = machine().memory().region_alloc( "sharedram", 0x4000, 1, ENDIANNESS_LITTLE )->base(); +} + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void dmv_k233_device::device_reset() +{ + m_enabled = false; +} + +void dmv_k233_device::io_write(address_space &space, int ifsel, offs_t offset, UINT8 data) +{ + if (ifsel == 1) + m_enabled = !m_enabled; +} + +//------------------------------------------------- +// read +//------------------------------------------------- + +bool dmv_k233_device::read(offs_t offset, UINT8 &data) +{ + if (m_enabled && offset >= 0xc000 && offset < 0x10000) + { + data = m_ram[offset & 0x3fff]; + return true; + } + + return false; +} + +//------------------------------------------------- +// write +//------------------------------------------------- + +bool dmv_k233_device::write(offs_t offset, UINT8 data) +{ + if (m_enabled && offset >= 0xc000 && offset < 0x10000) + { + m_ram[offset & 0x3fff] = data; + return true; + } + + return false; +} |