// license:BSD-3-Clause
// copyright-holders:R. Belmont
/***************************************************************************
awacs.c
AWACS/Singer style 16-bit audio I/O for '040 and PowerPC Macs
Emulation by R. Belmont
***************************************************************************/
#include "emu.h"
#include "awacs.h"
// device type definition
DEFINE_DEVICE_TYPE(AWACS, awacs_device, "awacs", "AWACS")
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// awacs_device - constructor
//-------------------------------------------------
awacs_device::awacs_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, AWACS, tag, owner, clock)
, device_sound_interface(mconfig, *this)
, m_stream(nullptr)
, m_play_ptr(0), m_buffer_size(0), m_buffer_num(0), m_playback_enable(false)
, m_dma_space(nullptr), m_dma_offset_0(0), m_dma_offset_1(0)
, m_timer(nullptr)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void awacs_device::device_start()
{
// create the stream
m_stream = machine().sound().stream_alloc(*this, 0, 2, 22050);
memset(m_regs, 0, sizeof(m_regs));
m_timer = timer_alloc(0, nullptr);
save_item(NAME(m_play_ptr));
save_item(NAME(m_buffer_size));
save_item(NAME(m_playback_enable));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void awacs_device::device_reset()
{
m_stream->update();
memset(m_regs, 0, sizeof(m_regs));
m_play_ptr = 0;
m_buffer_size = 0;
m_playback_enable = false;
m_dma_space = nullptr;
m_dma_offset_0 = m_dma_offset_1 = 0;
m_buffer_num = 0;
}
//-------------------------------------------------
// device_timer - called when our device timer expires
//-------------------------------------------------
void awacs_device::device_timer(emu_timer &timer, device_timer_id tid, int param, void *ptr)
{
m_stream->update();
}
//-------------------------------------------------
// sound_stream_update - handle update requests for
// our sound stream
//-------------------------------------------------
void awacs_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
{
stream_sample_t *outL, *outR;
int offset = (m_buffer_num == 0) ? m_dma_offset_0 : m_dma_offset_1;
outL = outputs[0];
outR = outputs[1];
if (m_playback_enable)
{
for (int i = 0; i < samples; i++)
{
outL[i] = (int16_t)m_dma_space->read_word(offset + m_play_ptr);
outR[i] = (int16_t)m_dma_space->read_word(offset + m_play_ptr + 2);
m_play_ptr += 4;
}
// out of buffer?
if (m_play_ptr >= m_buffer_size)
{
uint8_t bufflag[2] = { 0x40, 0x80 };
m_regs[0x18] |= bufflag[m_buffer_num];
m_buffer_num ^= 1;
m_play_ptr = 0;
}
}
else
{
for (int i = 0; i < samples; i++)
{
outL[i] = 0;
outR[i] = 0;
}
}
}
//-------------------------------------------------
// read - read from the chip's registers and internal RAM
//-------------------------------------------------
READ8_MEMBER( awacs_device::read )
{
return m_regs[offset];
}
//-------------------------------------------------
// write - write to the chip's registers and internal RAM
//-------------------------------------------------
WRITE8_MEMBER( awacs_device::write )
{
switch (offset)
{
case 0x8:
case 0x9:
m_regs[offset] = data;
m_buffer_size = (m_regs[8]<<6) | (m_regs[9]>>2);
// printf("buffer size = %x samples, %x bytes\n", m_buffer_size, m_buffer_size*4);
m_buffer_size *= 4; // samples * 16 bits * stereo
break;
case 0x10:
{
static const int rates[4] = { 22100, 29400, 44100, 22100 };
m_stream->set_sample_rate(rates[(data>>1)&3]);
// printf("rate %d, enable: %d\n", rates[(data>>1)&3], data & 1);
m_playback_enable = (data & 1) ? true : false;
if (m_playback_enable && !(m_regs[0x10]&1))
{
m_play_ptr = 0;
m_buffer_num = 0;
}
}
break;
case 0x18:
m_regs[offset] &= 0xf0;
m_regs[offset] |= (data & 0x0f);
m_regs[offset] &= ~(data & 0xf0);
return;
}
m_regs[offset] = data;
}
void awacs_device::set_dma_base(address_space &space, int offset0, int offset1)
{
m_dma_space = &space;
m_dma_offset_0 = offset0;
m_dma_offset_1 = offset1;
}