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// license:BSD-3-Clause
// copyright-holders:Sean Gonsalves
/***************************************************************************
Konami 007452 multiplier/divider
***************************************************************************/
#include "emu.h"
#include "k007452.h"
//**************************************************************************
// CONSTANTS
//**************************************************************************
// device type definition
DEFINE_DEVICE_TYPE(KONAMI_007452_MATH, k007452_device, "konami_007452", "Konami 007452 math chip")
//-------------------------------------------------
// k007452_device - constructor
//-------------------------------------------------
k007452_device::k007452_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
: device_t(mconfig, KONAMI_007452_MATH, tag, owner, clock)
{
}
//-------------------------------------------------
// read - read the registers
//-------------------------------------------------
uint8_t k007452_device::read(offs_t offset)
{
switch (offset & 7)
{
case 0: return m_multiply_result & 0xff;
case 1: return (m_multiply_result >> 8) & 0xff;
case 2: return m_divide_remainder & 0xff;
case 3: return (m_divide_remainder >> 8) & 0xff;
case 4: return m_divide_quotient & 0xff;
case 5: return (m_divide_quotient >> 8) & 0xff;
default: return 0;
}
}
//-------------------------------------------------
// write - write to the registers
//-------------------------------------------------
void k007452_device::write(offs_t offset, u8 data)
{
if (offset < 6) m_math_regs[offset] = data;
if (offset == 1)
{
// Starts multiplication process
m_multiply_result = m_math_regs[0] * m_math_regs[1];
}
else if (offset == 5)
{
// Starts division process
u16 dividend = (m_math_regs[4]<<8) + m_math_regs[5];
u16 divisor = (m_math_regs[2]<<8) + m_math_regs[3];
if (!divisor) {
m_divide_quotient = 0xffff;
m_divide_remainder = 0x0000;
} else {
m_divide_quotient = dividend / divisor;
m_divide_remainder = dividend % divisor;
}
}
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void k007452_device::device_start()
{
save_item(NAME(m_math_regs));
save_item(NAME(m_multiply_result));
save_item(NAME(m_divide_quotient));
save_item(NAME(m_divide_remainder));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void k007452_device::device_reset()
{
std::fill(std::begin(m_math_regs), std::end(m_math_regs), 0);
m_multiply_result = 0;
m_divide_quotient = 0;
m_divide_remainder = 0;
}
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