Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-05-12 00:58:53 +03:00
Code Issues Actions Packages Projects Releases Wiki Activity

8237dma - Added cascade mode support [Wilbert Pol]

Browse Source
This commit is contained in:
Miodrag Milanovic 2011-04-11 10:31:28 +00:00
parent c228f94320
commit 6fcb66bd02
2 changed files with 43 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
src/emu/machine/8237dma.c
View File

@ -306,6 +306,7 @@ void i8237_device::i8237_timerproc()
/* 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;
devcb_call_write_line(&m_out_hrq_func, m_hrq);
m_state = DMA8237_S0;
@ -330,19 +331,51 @@ void i8237_device::i8237_timerproc()
for confirmation. */
if ( m_hlda )
{
if ( m_command & 0x01 )
if ( DMA_MODE_TRANSFERMODE( m_chan[m_service_channel].m_mode ) == DMA8237_CASCADE_MODE )
{
/* Memory-to-memory transfers */
m_state = DMA8237_S11;
/* Cascade Mode, set DACK */
i8327_set_dack(m_service_channel);
/* Wait until peripheral is done */
m_state = DMA8237_SC;
}
else
{
/* Regular transfers */
m_state = DMA8237_S1;
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;
devcb_call_write_line(&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;
devcb_call_write_line(&m_out_eop_func, m_eop ? ASSERT_LINE : CLEAR_LINE);
}
break;
case DMA8237_S1: /* Output A8-A15 */
m_state = DMA8237_S2;
break;
@ -422,16 +455,6 @@ void i8237_device::i8237_timerproc()
m_state = m_chan[channel].m_high_address_changed ? DMA8237_S1 : DMA8237_S2;
}
break;
case DMA8237_CASCADE_MODE:
if ( ! ( m_drq & ( 0x01 << channel ) ) )
{
m_hrq = 0;
m_hlda = 0;
devcb_call_write_line(&m_out_hrq_func, m_hrq);
m_state = DMA8237_SI;
}
break;
}
/* Check if EOP output needs to be asserted */
@ -443,7 +466,10 @@ void i8237_device::i8237_timerproc()
}
/* clear DACK */
i8327_set_dack(-1);
if ( m_state == DMA8237_SI )
{
i8327_set_dack(-1);
}
break;
case DMA8237_S11: /* Output A8-A15 */

1
src/emu/machine/8237dma.h
View File

@ -143,6 +143,7 @@ private:
DMA8237_SI, /* Idle state */
DMA8237_S0, /* HRQ has been triggered, waiting to receive HLDA */
// DMA8237_SW, /* Wait state */
DMA8237_SC, /* Cascade mode, waiting for peripheral */
/* Normal transfer states */
DMA8237_S1, /* Output A8-A15; only used when A8-A15 really needs to be output */