static BYTE sid_read_chip(WORD addr, int chipno)
{
int val = -1;
addr &= 0x1f;
machine_handle_pending_alarms(0);
#ifdef HAVE_MOUSE
if (chipno == 0 && (addr == 0x19 || addr == 0x1a)) {
if ((maincpu_clk ^ pot_cycle) & ~511) {
pot_cycle = maincpu_clk & ~511; /* simplistic 512 cycle sampling */
if (_mouse_enabled) {
val_pot_x = mouse_get_x();
val_pot_y = mouse_get_y();
} else if (lightpen_enabled) {
val_pot_x = lightpen_read_button_x();
val_pot_y = lightpen_read_button_y();
} else {
val_pot_x = 0xff;
val_pot_y = 0xff;
}
}
val = (addr == 0x19) ? val_pot_x : val_pot_y;
} else
#endif
{
if (machine_class == VICE_MACHINE_C64SC
|| machine_class == VICE_MACHINE_SCPU64) {
/* On x64sc, the read/write calls both happen before incrementing
the clock, so don't mess with maincpu_clk here. */
val = sid_read_func(addr, chipno);
} else {
/* Account for that read functions in VICE are called _before_
incrementing the clock. */
maincpu_clk++;
val = sid_read_func(addr, chipno);
maincpu_clk--;
}
}
/* Fallback when sound is switched off. */
if (val < 0) {
if (addr == 0x19 || addr == 0x1a) {
val = 0xff;
} else {
if (addr == 0x1b || addr == 0x1c) {
val = maincpu_clk % 256;
} else {
val = 0;
}
}
}
lastsidread = val;
return val;
}
/* write register value to sid */
static void sid_store_chip(WORD addr, BYTE byte, int chipno)
{
addr &= 0x1f;
siddata[chipno][addr] = byte;
/* WARNING: assumes `maincpu_rmw_flag' is 0 or 1. */
machine_handle_pending_alarms(maincpu_rmw_flag + 1);
if (maincpu_rmw_flag) {
maincpu_clk--;
sid_store_func(addr, lastsidread, chipno);
maincpu_clk++;
}
sid_store_func(addr, byte, chipno);
}
