inline void am9517a_device::set_eop(int state)
{
if (m_eop != state)
{
m_out_eop_func(state);
m_eop = state;
}
}
void i8237_device::i8237_timerproc()
{
/* Check if operation is disabled */
if ( m_command & 0x04 )
{
return;
}
switch ( m_state )
{
case DMA8237_SI:
{
/* Make sure EOP is high */
if ( !m_eop )
{
m_eop = 1;
m_out_eop_func(m_eop ? ASSERT_LINE : CLEAR_LINE);
}
/* Check if a new DMA request has been received. */
/* Bit 6 of the command register determines whether the DREQ signals are active
high or active low. */
UINT16 pending_request = ( ( m_command & 0x40 ) ? ~m_drq : m_drq ) & ~m_mask;
if ( pending_request & 0x0f )
{
int prio_channel = 0;
/* Determine the channel that should be serviced */
int channel = ( m_command & 0x10 ) ? m_last_service_channel : 3;
for ( int i = 0; i < 4; i++ )
{
if ( pending_request & ( 1 << channel ) )
{
prio_channel = channel;
}
channel = ( channel - 1 ) & 0x03;
}
/* Store the channel we will be servicing and go to the next state */
m_service_channel = prio_channel;
m_last_service_channel = prio_channel;
m_hrq = 1;
m_out_hrq_func(m_hrq);
m_state = DMA8237_S0;
m_timer->enable( true );
}
else if (m_command == 3 && (m_drq & 1))
{
/* Memory-to-memory transfers */
m_hlda = 1;
m_state = DMA8237_S0;
}
else
{
m_timer->enable( false );
}
break;
}
case DMA8237_S0:
/* S0 is the first of the DMA service. We have requested a hold but are waiting
for confirmation. */
if ( m_hlda )
{
if ( DMA_MODE_TRANSFERMODE( m_chan[m_service_channel].m_mode ) == DMA8237_CASCADE_MODE )
{
/* Cascade Mode, set DACK */
i8327_set_dack(m_service_channel);
/* Wait until peripheral is done */
m_state = DMA8237_SC;
}
else
{
if ( m_command & 0x01 )
{
/* Memory-to-memory transfers */
m_state = DMA8237_S11;
}
else
{
/* Regular transfers */
m_state = DMA8237_S1;
}
}
}
break;
case DMA8237_SC: /* Cascade mode, waiting until peripheral is done */
if ( ! ( m_drq & ( 0x01 << m_service_channel ) ) )
{
m_hrq = 0;
m_hlda = 0;
m_out_hrq_func(m_hrq);
m_state = DMA8237_SI;
/* Clear DACK */
i8327_set_dack(-1);
}
/* Not sure if this is correct, documentation is not clear */
/* Check if EOP output needs to be asserted */
if ( m_status & ( 0x01 << m_service_channel ) )
{
m_eop = 0;
m_out_eop_func(m_eop ? ASSERT_LINE : CLEAR_LINE);
}
break;
case DMA8237_S1: /* Output A8-A15 */
m_state = DMA8237_S2;
break;
case DMA8237_S2: /* Output A7-A0 */
/* set DACK */
i8327_set_dack(m_service_channel);
/* Check for compressed timing */
if ( m_command & 0x08 )
{
m_state = DMA8237_S4;
}
else
{
m_state = DMA8237_S3;
}
break;
case DMA8237_S3: /* Initiate read */
i8237_do_read();
m_state = DMA8237_S4;
break;
case DMA8237_S4: /* Perform read/write */
/* Perform read when in compressed timing mode */
if ( m_command & 0x08 )
{
i8237_do_read();
}
/* Perform write */
i8237_do_write();
/* Advance */
i8237_advance();
{
int channel = m_service_channel;
switch( DMA_MODE_TRANSFERMODE( m_chan[channel].m_mode ) )
{
case DMA8237_DEMAND_MODE:
/* Check for terminal count or EOP signal or DREQ begin de-asserted */
if ( ( m_status & ( 0x01 << channel ) ) || !m_eop || !( m_drq & ( 0x01 << channel ) ) )
{
m_hrq = 0;
m_hlda = 0;
m_out_hrq_func(m_hrq);
m_state = DMA8237_SI;
}
else
{
m_state = m_chan[channel].m_high_address_changed ? DMA8237_S1 : DMA8237_S2;
}
break;
case DMA8237_SINGLE_MODE:
m_hrq = 0;
m_hlda = 0;
m_out_hrq_func(m_hrq);
m_state = DMA8237_SI;
break;
case DMA8237_BLOCK_MODE:
/* Check for terminal count or EOP signal */
if ( ( m_status & ( 0x01 << channel ) ) || !m_eop )
{
m_hrq = 0;
m_hlda = 0;
m_out_hrq_func(m_hrq);
m_state = DMA8237_SI;
}
else
{
m_state = m_chan[channel].m_high_address_changed ? DMA8237_S1 : DMA8237_S2;
}
break;
}
/* Check if EOP output needs to be asserted */
if ( m_status & ( 0x01 << channel ) )
{
m_eop = 0;
m_out_eop_func(m_eop ? ASSERT_LINE : CLEAR_LINE);
}
}
/* clear DACK */
if ( m_state == DMA8237_SI )
{
i8327_set_dack(-1);
}
break;
case DMA8237_S11: /* Output A8-A15 */
// logerror("###### dma8237_timerproc %s: from %04x count=%x to %04x count=%x\n", tag(),
// m_chan[0].m_address, m_chan[0].m_count,
// m_chan[1].m_address, m_chan[1].m_count);
// FIXME: this will copy bytes correct, but not 16 bit words
m_temporary_data = m_in_memr_func(m_chan[0].m_address);
m_out_memw_func(m_chan[1].m_address, m_temporary_data);
m_service_channel = 0;
/* Advance */
i8237_advance();
// advance destination channel as well
m_chan[1].m_count--;
m_chan[1].m_address++;
if (m_chan[0].m_count == 0xFFFF || m_chan[1].m_count == 0xFFFF) {
m_hrq = 0;
m_hlda = 0;
m_out_hrq_func(m_hrq);
m_state = DMA8237_SI;
m_status |= 3; // set TC for channel 0 and 1
m_drq &= ~3; // clear drq for channel 0 and 1
// logerror("!!! dma8237_timerproc DMA8237_S11 %s: m_drq=%x m_command=%x\n", tag(), m_drq, m_command);
}
break;
}
}