static TIMER_CALLBACK( dma8257_timerproc )
{
const device_config *device = (const device_config *)ptr;
dma8257_t *dma8257 = get_safe_token(device);
int i, channel = 0, rr;
int done;
rr = DMA_MODE_ROTPRIO(dma8257->mode) ? dma8257->rr : 0;
for (i = 0; i < DMA8257_NUM_CHANNELS; i++)
{
channel = (i + rr) % DMA8257_NUM_CHANNELS;
if ((dma8257->status & (1 << channel)) == 0)
if (dma8257->mode & dma8257->drq & (1 << channel))
break;
}
done = dma8257_do_operation(device, channel);
dma8257->rr = (channel + 1) & 0x03;
if (done)
{
dma8257->drq &= ~(0x01 << channel);
dma8257_update_status(device);
if (!(DMA_MODE_AUTOLOAD(dma8257->mode) && channel==2)) {
if (DMA_MODE_TCSTOP(dma8257->mode)) {
dma8257->mode &= ~(0x01 << channel);
}
}
}
}
void i8257_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
switch (id)
{
case TIMER_OPERATION:
{
int i, channel = 0, rr;
int done;
rr = DMA_MODE_ROTPRIO(m_mode) ? m_rr : 0;
for (i = 0; i < I8257_NUM_CHANNELS; i++)
{
channel = (i + rr) % I8257_NUM_CHANNELS;
if ((m_status & (1 << channel)) == 0)
{
if (m_mode & m_drq & (1 << channel))
{
break;
}
}
}
done = i8257_do_operation(channel);
m_rr = (channel + 1) & 0x03;
if (done)
{
m_drq &= ~(0x01 << channel);
i8257_update_status();
if (!(DMA_MODE_AUTOLOAD(m_mode) && channel==2))
{
if (DMA_MODE_TCSTOP(m_mode))
{
m_mode &= ~(0x01 << channel);
}
}
}
break;
}
case TIMER_MSBFLIP:
m_msb ^= 1;
break;
case TIMER_DRQ_SYNC:
{
int channel = param >> 1;
int state = param & 0x01;
/* normalize state */
if (state)
{
m_drq |= 0x01 << channel;
m_address[channel] = m_registers[channel * 2];
m_count[channel] = m_registers[channel * 2 + 1] & 0x3FFF;
m_rwmode[channel] = m_registers[channel * 2 + 1] >> 14;
/* clear channel TC */
m_status &= ~(0x01 << channel);
}
else
m_drq &= ~(0x01 << channel);
i8257_update_status();
break;
}
}