int z80pio_interrupt( int which )
{
z80pio *pio = pios + which;
int ch = 0;
/* port A */
if( pio->int_state[0] == Z80_INT_REQ )
{
pio->int_state[0] |= Z80_INT_IEO;
} if( pio->int_state[0] == 0 )
{
/* port B */
ch = 1;
if( pio->int_state[1] == Z80_INT_REQ )
{
pio->int_state[1] |= Z80_INT_IEO;
}
else
{
if (errorlog) fprintf(errorlog,"PIO entry INT : non IRQ\n");
ch = 0;
}
}
z80pio_interrupt_check( pio );
return pio->vector[ch];
}
static void z80pio_check_irq( z80pio *pio , int ch )
{
int irq = 0;
int data;
int old_state;
if( pio->enable[ch] & PIO_INT_ENABLE )
{
if( pio->mode[ch] == PIO_MODE3 )
{
data = pio->in[ch] & pio->dir[ch]; /* input data only */
data &= ~pio->mask[ch]; /* mask follow */
if( !(pio->enable[ch]&PIO_INT_HIGH) )/* active level */
data ^= pio->mask[ch]; /* active low */
if( pio->enable[ch]&PIO_INT_AND ) /* logic */
{ if( data == pio->mask[ch] ) irq = 1; }
else { if( data == 0 ) irq = 1; }
/* if portB , portA mode 2 check */
if( ch && (pio->mode[0]==PIO_MODE2) )
{
if( pio->rdy[ch] == 0 ) irq = 1;
}
}
else if( pio->rdy[ch] == 0 ) irq = 1;
}
old_state = pio->int_state[ch];
if( irq ) pio->int_state[ch] |= Z80_INT_REQ;
else pio->int_state[ch] &= ~Z80_INT_REQ;
if( old_state != pio->int_state[ch] )
z80pio_interrupt_check( pio );
}
void z80pio_reti( int which )
{
z80pio *pio = pios + which;
if( pio->int_state[0] & Z80_INT_IEO )
{
pio->int_state[0] &= ~Z80_INT_IEO;
} else if( pio->int_state[1] & Z80_INT_IEO )
{
pio->int_state[1] &= ~Z80_INT_IEO;
}
/* set next interrupt stattus */
z80pio_interrupt_check( pio );
}
void z80pio_reset (int which)
{
z80pio *pio = pios + which;
int i;
for( i = 0 ; i <= 1 ; i++){
pio->mask[i] = 0xff; /* mask all on */
pio->enable[i] = 0x00; /* disable */
pio->mode[i] = 0x01; /* mode input */
pio->dir[i] = 0x01; /* dir input */
pio->rdy[i] = 0x00; /* RDY = low */
pio->out[i] = 0x00; /* outdata = 0 */
pio->int_state[i] = 0;
}
z80pio_interrupt_check( pio );
}
static void z80pio_update_strobe(int which, int ch, int state)
{
z80pio *pio = pios + which;
if (ch) ch=1;
switch (pio->mode[ch])
{
/* output mode */
case PIO_MODE0:
{
/* ensure valid */
state = state & 0x01;
/* strobe changed state? */
if ((pio->strobe[ch]^state)!=0)
{
/* yes */
if (state!=0)
{
/* positive edge */
logerror("PIO-%c positive strobe\n",'A'+ch );
/* ready is now inactive */
z80pio_set_rdy(pio, ch, 0);
/* int enabled? */
if (pio->enable[ch] & PIO_INT_ENABLE)
{
/* trigger an int request */
pio->int_state[ch] |= Z80_INT_REQ;
}
}
}
/* store strobe state */
pio->strobe[ch] = state;
/* check interrupt */
z80pio_interrupt_check( pio );
}
break;
default:
break;
}
}
