// license:BSD-3-Clause
// copyright-holders:Curt Coder
/**********************************************************************
Conitec PROF-80 Memory Management Unit emulation
**********************************************************************/
#include "prof80mmu.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
const device_type PROF80_MMU = &device_creator<prof80_mmu_device>;
DEVICE_ADDRESS_MAP_START( z80_program_map, 8, prof80_mmu_device )
AM_RANGE(0x0000, 0xffff) AM_READWRITE(program_r, program_w)
ADDRESS_MAP_END
static ADDRESS_MAP_START( program_map, AS_PROGRAM, 8, prof80_mmu_device )
ADDRESS_MAP_END
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// prof80_mmu_device - constructor
//-------------------------------------------------
prof80_mmu_device::prof80_mmu_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
: device_t(mconfig, PROF80_MMU, "PROF80_MMU", tag, owner, clock, "prof80_mmu", __FILE__),
device_memory_interface(mconfig, *this),
m_program_space_config("program", ENDIANNESS_LITTLE, 8, 20, 0, *ADDRESS_MAP_NAME(program_map))
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void prof80_mmu_device::device_start()
{
// state saving
save_item(NAME(m_blk));
save_item(NAME(m_enabled));
}
//-------------------------------------------------
// memory_space_config - return a description of
// any address spaces owned by this device
//-------------------------------------------------
const address_space_config *prof80_mmu_device::memory_space_config(address_spacenum spacenum) const
{
return (spacenum == AS_PROGRAM) ? &m_program_space_config : nullptr;
}
//-------------------------------------------------
// par_w -
//-------------------------------------------------
WRITE8_MEMBER( prof80_mmu_device::par_w )
{
int bank = offset >> 12;
m_blk[bank] = (data & 0x0f) ^ 0x0f;
}
//-------------------------------------------------
// mme_w -
//-------------------------------------------------
WRITE_LINE_MEMBER( prof80_mmu_device::mme_w )
{
m_enabled = (state == 1);
}
//-------------------------------------------------
// program_r - program space read
//-------------------------------------------------
READ8_MEMBER( prof80_mmu_device::program_r )
{
if (m_enabled)
{
int bank = offset >> 12;
offset |= m_blk[bank] << 16;
}
else
{
offset |= 0xf0000;
}
return this->space(AS_PROGRAM).read_byte(offset);
}
//-------------------------------------------------
// program_w - program space write
//-------------------------------------------------
WRITE8_MEMBER( prof80_mmu_device::program_w )
{
if (m_enabled)
{
int bank = offset >> 12;
offset |= m_blk[bank] << 16;
}
else
{
offset |= 0xf0000;
}
this->space(AS_PROGRAM).write_byte(offset, data);
}