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// license:BSD-3-Clause
// copyright-holders:Curt Coder
/**********************************************************************
Wang PC-PM031-B Extended Memory Board emulation
**********************************************************************/
#include "emu.h"
#include "emb.h"
//**************************************************************************
// MACROS/CONSTANTS
//**************************************************************************
#define LOG 0
#define OPTION_ID 0x3f
#define RAM_SIZE 0x40000
#define A19_A18_A17 ((offset >> 16) & 0x07)
#define BASE(bank) ((m_option >> (bank * 4)) & 0x07)
#define ENABLE(bank) BIT(m_option, (bank * 4) + 3)
#define RAM_BANK(bank) m_ram[(bank * 0x10000) | (offset & 0xffff)]
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
DEFINE_DEVICE_TYPE(WANGPC_EMB, wangpc_emb_device, "wangpc_emb", "Wang PC-PM031-B Extended Memory Board")
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// wangpc_emb_device - constructor
//-------------------------------------------------
wangpc_emb_device::wangpc_emb_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
device_t(mconfig, WANGPC_EMB, tag, owner, clock),
device_wangpcbus_card_interface(mconfig, *this),
m_ram(*this, "ram"),
m_option(0), m_parity_error(0), m_parity_odd(0)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void wangpc_emb_device::device_start()
{
// allocate memory
m_ram.allocate(RAM_SIZE);
// state saving
save_item(NAME(m_option));
save_item(NAME(m_parity_error));
save_item(NAME(m_parity_odd));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void wangpc_emb_device::device_reset()
{
m_option = 0;
m_parity_error = 0;
m_parity_odd = 1;
}
//-------------------------------------------------
// wangpcbus_mrdc_r - memory read
//-------------------------------------------------
uint16_t wangpc_emb_device::wangpcbus_mrdc_r(offs_t offset, uint16_t mem_mask)
{
uint16_t data = 0xffff;
for (int bank = 0; bank < 4; bank++)
{
if (ENABLE(bank) && (A19_A18_A17 == BASE(bank)))
{
data &= RAM_BANK(bank);
}
}
return data;
}
//-------------------------------------------------
// wangpcbus_amwc_w - memory write
//-------------------------------------------------
void wangpc_emb_device::wangpcbus_amwc_w(offs_t offset, uint16_t mem_mask, uint16_t data)
{
for (int bank = 0; bank < 4; bank++)
{
if (ENABLE(bank) && (A19_A18_A17 == BASE(bank)))
{
RAM_BANK(bank) = data;
}
}
}
//-------------------------------------------------
// wangpcbus_iorc_r - I/O read
//-------------------------------------------------
uint16_t wangpc_emb_device::wangpcbus_iorc_r(offs_t offset, uint16_t mem_mask)
{
uint16_t data = 0xffff;
if (sad(offset))
{
switch (offset & 0x7f)
{
case 0xc0/2:
data = m_option;
break;
case 0xfe/2:
data = 0xfc00 | (m_parity_odd << 9) | (m_parity_error << 8) | OPTION_ID;
break;
}
logerror("emb read %06x:%02x\n", offset*2, data);
}
return data;
}
//-------------------------------------------------
// wangpcbus_aiowc_w - I/O write
//-------------------------------------------------
void wangpc_emb_device::wangpcbus_aiowc_w(offs_t offset, uint16_t mem_mask, uint16_t data)
{
if (sad(offset))
{
logerror("emb write %06x:%02x\n", offset*2, data);
switch (offset & 0x7f)
{
case 0xc0/2:
m_option = data;
break;
case 0xce/2:
m_parity_error = 0;
break;
case 0xfc/2:
device_reset();
break;
case 0xfe/2:
m_parity_odd = BIT(data, 9);
break;
}
}
}
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