static TIMER_DEVICE_CALLBACK( vball_scanline )
{
vball_state *state = timer.machine().driver_data<vball_state>();
int scanline = param;
int screen_height = timer.machine().primary_screen->height();
int vcount_old = scanline_to_vcount((scanline == 0) ? screen_height - 1 : scanline - 1);
int vcount = scanline_to_vcount(scanline);
/* Update to the current point */
if (scanline > 0)
{
timer.machine().primary_screen->update_partial(scanline - 1);
}
/* IRQ fires every on every 8th scanline */
if (!(vcount_old & 8) && (vcount & 8))
{
cputag_set_input_line(timer.machine(), "maincpu", M6502_IRQ_LINE, ASSERT_LINE);
}
/* NMI fires on scanline 248 (VBL) and is latched */
if (vcount == 0xf8)
{
cputag_set_input_line(timer.machine(), "maincpu", INPUT_LINE_NMI, ASSERT_LINE);
}
/* Save the scroll x register value */
if (scanline < 256)
{
state->m_vb_scrollx[255 - scanline] = (state->m_vb_scrollx_hi + state->m_vb_scrollx_lo + 4);
}
}
static TIMER_DEVICE_CALLBACK( xain_scanline )
{
xain_state *state = timer.machine().driver_data<xain_state>();
int scanline = param;
int screen_height = timer.machine().primary_screen->height();
int vcount_old = scanline_to_vcount((scanline == 0) ? screen_height - 1 : scanline - 1);
int vcount = scanline_to_vcount(scanline);
/* update to the current point */
if (scanline > 0)
{
timer.machine().primary_screen->update_partial(scanline - 1);
}
/* FIRQ (IMS) fires every on every 8th scanline (except 0) */
if (!(vcount_old & 8) && (vcount & 8))
{
cputag_set_input_line(timer.machine(), "maincpu", M6809_FIRQ_LINE, ASSERT_LINE);
}
/* NMI fires on scanline 248 (VBL) and is latched */
if (vcount == 0xf8)
{
cputag_set_input_line(timer.machine(), "maincpu", INPUT_LINE_NMI, ASSERT_LINE);
}
/* VBLANK input bit is held high from scanlines 248-255 */
if (vcount >= 248-1) // -1 is a hack - see notes above
{
state->m_vblank = 1;
}
else
{
state->m_vblank = 0;
}
}