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core, revisit ym2612 busy flag implementation

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kub 2024-06-22 23:12:31 +02:00
parent e948a120ed
commit f5c022a8e4
5 changed files with 24 additions and 16 deletions
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13
pico/memory.c
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@ -1174,7 +1174,7 @@ static int ym2612_write_local(u32 a, u32 d, int is_from_z80)
// the busy flag in the YM2612 status is actually a 32 cycle timer
// (89.6 Z80 cycles), triggered by any write to the data port.
Pico.t.ym2612_busy = (cycles + 90) << 8; // Q8 for convenience
Pico.t.ym2612_busy = (cycles << 8) + YMBUSY_ZCYCLES; // Q8 for convenience
switch (addr)
{
@ -1284,9 +1284,11 @@ static u32 ym2612_read_local_68k(void)
void ym2612_pack_state(void)
{
// timers are saved as tick counts, in 16.16 int format
int tac, tat = 0, tbc, tbt = 0;
int tac, tat = 0, tbc, tbt = 0, busy = 0;
tac = 1024 - ym2612.OPN.ST.TA;
tbc = 256 - ym2612.OPN.ST.TB;
if (Pico.t.ym2612_busy > 0)
busy = cycles_z80_to_68k(Pico.t.ym2612_busy);
if (Pico.t.timer_a_next_oflow != TIMER_NO_OFLOW)
tat = (int)((double)(Pico.t.timer_a_step - Pico.t.timer_a_next_oflow)
/ (double)Pico.t.timer_a_step * tac * 65536);
@ -1301,12 +1303,12 @@ void ym2612_pack_state(void)
YM2612PicoStateSave2_940(tat, tbt);
else
#endif
YM2612PicoStateSave2(tat, tbt);
YM2612PicoStateSave2(tat, tbt, busy);
}
void ym2612_unpack_state(void)
{
int i, ret, tac, tat, tbc, tbt;
int i, ret, tac, tat, tbc, tbt, busy = 0;
YM2612PicoStateLoad();
// feed all the registers and update internal state
@ -1336,12 +1338,13 @@ void ym2612_unpack_state(void)
ret = YM2612PicoStateLoad2_940(&tat, &tbt);
else
#endif
ret = YM2612PicoStateLoad2(&tat, &tbt);
ret = YM2612PicoStateLoad2(&tat, &tbt, &busy);
if (ret != 0) {
elprintf(EL_STATUS, "old ym2612 state");
return; // no saved timers
}
Pico.t.ym2612_busy = cycles_68k_to_z80(busy);
tac = (1024 - ym2612.OPN.ST.TA) << 16;
tbc = (256 - ym2612.OPN.ST.TB) << 16;
if (ym2612.OPN.ST.mode & 1)