// license:BSD-3-Clause
// copyright-holders:hap
/**********************************************************************
IDT7200 series 9-bit Asynchronous FIFO Emulation
TODO:
- retransmit (RT pin)
- cascaded width expansion mode (when needed)
**********************************************************************/
#include "emu.h"
#include "machine/7200fifo.h"
DEFINE_DEVICE_TYPE(IDT7200, idt7200_device, "idt7200", "IDT7200 FIFO (256x9)")
DEFINE_DEVICE_TYPE(IDT7201, idt7201_device, "idt7201", "IDT7201 FIFO (512x9)")
DEFINE_DEVICE_TYPE(IDT7202, idt7202_device, "idt7202", "IDT7202 FIFO (1024x9)")
//-------------------------------------------------
// fifo7200_device - constructor
//-------------------------------------------------
fifo7200_device::fifo7200_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, int size)
: device_t(mconfig, type, tag, owner, (uint32_t)0),
m_ram_size(size),
m_read_ptr(0), m_write_ptr(0), m_ef(0), m_ff(0), m_hf(0),
m_ef_handler(*this),
m_ff_handler(*this),
m_hf_handler(*this)
{
}
//-------------------------------------------------
// idt7200_device - constructor
//-------------------------------------------------
idt7200_device::idt7200_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: fifo7200_device(mconfig, IDT7200, tag, owner, 0x100)
{
}
//-------------------------------------------------
// idt7201_device - constructor
//-------------------------------------------------
idt7201_device::idt7201_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: fifo7200_device(mconfig, IDT7201, tag, owner, 0x200)
{
}
//-------------------------------------------------
// idt7202_device - constructor
//-------------------------------------------------
idt7202_device::idt7202_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: fifo7200_device(mconfig, IDT7202, tag, owner, 0x400)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void fifo7200_device::device_start()
{
assert(m_ram_size > 1 && ~m_ram_size & 1);
m_buffer.resize(m_ram_size);
// resolve callbacks
m_ef_handler.resolve_safe();
m_ff_handler.resolve_safe();
m_hf_handler.resolve_safe();
// state save
save_item(NAME(m_buffer));
save_item(NAME(m_read_ptr));
save_item(NAME(m_write_ptr));
save_item(NAME(m_ef));
save_item(NAME(m_ff));
save_item(NAME(m_hf));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void fifo7200_device::device_reset()
{
// master reset
std::fill(m_buffer.begin(), m_buffer.end(), 0);
m_read_ptr = 0;
m_write_ptr = 0;
m_ef = 1;
m_ff = 0;
m_hf = 0;
m_ef_handler(!m_ef);
m_ff_handler(!m_ff);
m_hf_handler(!m_hf);
}
void fifo7200_device::fifo_write(uint16_t data)
{
if (m_ff)
{
logerror("IDT7200 %s fifo_write overflow!\n", tag());
return;
}
m_buffer[m_write_ptr] = data & 0x1ff;
m_write_ptr = (m_write_ptr + 1) % m_ram_size;
// update flags
if (m_ef)
{
m_ef = 0;
m_ef_handler(!m_ef);
}
else if (m_read_ptr == m_write_ptr)
{
m_ff = 1;
m_ff_handler(!m_ff);
}
else if (((m_read_ptr + 1 + m_ram_size / 2) % m_ram_size) == m_write_ptr)
{
m_hf = 1;
m_hf_handler(!m_hf);
}
}
uint16_t fifo7200_device::fifo_read()
{
if (m_ef)
{
if (!machine().side_effects_disabled())
logerror("IDT7200 %s fifo_read underflow!\n", tag());
return 0x1ff;
}
uint16_t ret = m_buffer[m_read_ptr];
if (!machine().side_effects_disabled())
{
m_read_ptr = (m_read_ptr + 1) % m_ram_size;
// update flags
if (m_ff)
{
m_ff = 0;
m_ff_handler(!m_ff);
}
else if (m_read_ptr == m_write_ptr)
{
m_ef = 1;
m_ef_handler(!m_ef);
}
else if (((m_read_ptr + m_ram_size / 2) % m_ram_size) == m_write_ptr)
{
m_hf = 0;
m_hf_handler(!m_hf);
}
}
return ret;
}