static int dma8237_do_operation(int which, int channel)
{
int done;
UINT8 data;
UINT8 mode;
mode = dma[which].chan[channel].mode;
switch(DMA_MODE_OPERATION(mode)) {
case 1:
data = dma[which].intf->channel_read_func[channel]();
dma[which].intf->memory_write_func(channel, dma[which].chan[channel].address, data);
dma[which].chan[channel].address += DMA_MODE_DIRECTION(mode);
dma[which].chan[channel].count--;
done = (dma[which].chan[channel].count == 0xFFFF);
break;
case 2:
data = dma[which].intf->memory_read_func(channel, dma[which].chan[channel].address);
dma[which].intf->channel_write_func[channel](data);
dma[which].chan[channel].address += DMA_MODE_DIRECTION(mode);
dma[which].chan[channel].count--;
done = (dma[which].chan[channel].count == 0xFFFF);
break;
default:
done = TRUE;
break;
}
return done;
}
void i8237_device::i8237_advance()
{
int channel = m_service_channel;
int mode = m_chan[channel].m_mode;
switch ( DMA_MODE_OPERATION( mode ) )
{
case DMA8237_VERIFY_TRANSFER:
case DMA8237_WRITE_TRANSFER:
case DMA8237_READ_TRANSFER:
m_chan[channel].m_high_address_changed = 0;
if ( DMA_MODE_DIRECTION( mode ) )
{
m_chan[channel].m_address -= 1;
if ( ( m_chan[channel].m_address & 0xFF ) == 0xFF )
{
m_chan[channel].m_high_address_changed = 1;
}
}
else
{
m_chan[channel].m_address += 1;
if ( ( m_chan[channel].m_address & 0xFF ) == 0x00 )
{
m_chan[channel].m_high_address_changed = 1;
}
}
m_chan[channel].m_count--;
if ( m_chan[channel].m_count == 0xFFFF )
{
/* Set TC bit for this channel */
m_status |= ( 0x01 << channel );
if ( DMA_MODE_AUTO_INIT( mode ) )
{
m_chan[channel].m_address = m_chan[channel].m_base_address;
m_chan[channel].m_count = m_chan[channel].m_base_count;
m_chan[channel].m_high_address_changed = 1;
}
else
{
m_mask |= ( 0x01 << channel );
}
}
break;
case DMA8237_ILLEGAL_TRANSFER:
break;
}
}
