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// license:BSD-3-Clause
// copyright-holders:Nigel Barnes
/**********************************************************************
Spectrum Currah MicroSource emulation
**********************************************************************/
#include "emu.h"
#include "usource.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
DEFINE_DEVICE_TYPE(SPECTRUM_USOURCE, spectrum_usource_device, "spectrum_usource", "Spectrum Currah \xC2\xB5Source")
//-------------------------------------------------
// ROM( usource )
//-------------------------------------------------
ROM_START( usource )
ROM_REGION(0x2000, "rom", 0)
ROM_LOAD("microsource.rom", 0x0000, 0x2000, CRC(8e9b67d0) SHA1(fae53678a85ba503b77ed2d877de2635b284eef1))
ROM_END
//-------------------------------------------------
// rom_region - device-specific ROM region
//-------------------------------------------------
const tiny_rom_entry *spectrum_usource_device::device_rom_region() const
{
return ROM_NAME( usource );
}
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// spectrum_usource_device - constructor
//-------------------------------------------------
spectrum_usource_device::spectrum_usource_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
device_t(mconfig, SPECTRUM_USOURCE, tag, owner, clock),
device_spectrum_expansion_interface(mconfig, *this),
m_rom(*this, "rom")
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void spectrum_usource_device::device_start()
{
save_item(NAME(m_romcs));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void spectrum_usource_device::device_reset()
{
m_romcs = 0;
}
//**************************************************************************
// IMPLEMENTATION
//**************************************************************************
READ_LINE_MEMBER(spectrum_usource_device::romcs)
{
return m_romcs;
}
void spectrum_usource_device::opcode_fetch(offs_t offset)
{
if (!machine().side_effects_disabled() && (offset == 0x2bae))
{
m_romcs = !m_romcs;
}
}
uint8_t spectrum_usource_device::mreq_r(offs_t offset)
{
return m_rom->base()[offset & 0x1fff];
}
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