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sound, improve ym2612 timers implementation

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kub 2023-06-22 22:18:47 +00:02
parent e0c4dac19c
commit c3d70d1305
4 changed files with 15 additions and 18 deletions
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13
pico/memory.c
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@ -1136,31 +1136,26 @@ static int ym2612_write_local(u32 a, u32 d, int is_from_z80)
: ((ym2612.OPN.ST.TA & 0x3fc)|(d&3));
if (ym2612.OPN.ST.TA != TAnew)
{
int cycles = is_from_z80 ? z80_cyclesDone() : z80_cycles_from_68k();
ym2612_sync_timers(cycles, ym2612.OPN.ST.mode, ym2612.OPN.ST.mode);
//elprintf(EL_STATUS, "timer a set %i", TAnew);
ym2612.OPN.ST.TA = TAnew;
//ym2612.OPN.ST.TAC = (1024-TAnew)*18;
//ym2612.OPN.ST.TAT = 0;
Pico.t.timer_a_step = TIMER_A_TICK_ZCYCLES * (1024 - TAnew);
if (ym2612.OPN.ST.mode & 1) {
// this is not right, should really be done on overflow only
int cycles = is_from_z80 ? z80_cyclesDone() : z80_cycles_from_68k();
Pico.t.timer_a_next_oflow = (cycles << 8) + Pico.t.timer_a_step;
}
elprintf(EL_YMTIMER, "timer a set to %i, %i", 1024 - TAnew, Pico.t.timer_a_next_oflow>>8);
}
return 0;
}
case 0x26: // timer B
if (ym2612.OPN.ST.TB != d) {
int cycles = is_from_z80 ? z80_cyclesDone() : z80_cycles_from_68k();
ym2612_sync_timers(cycles, ym2612.OPN.ST.mode, ym2612.OPN.ST.mode);
//elprintf(EL_STATUS, "timer b set %i", d);
ym2612.OPN.ST.TB = d;
//ym2612.OPN.ST.TBC = (256-d) * 288;
//ym2612.OPN.ST.TBT = 0;
Pico.t.timer_b_step = TIMER_B_TICK_ZCYCLES * (256 - d); // 262800
if (ym2612.OPN.ST.mode & 2) {
int cycles = is_from_z80 ? z80_cyclesDone() : z80_cycles_from_68k();
Pico.t.timer_b_next_oflow = (cycles << 8) + Pico.t.timer_b_step;
}
elprintf(EL_YMTIMER, "timer b set to %i, %i", 256 - d, Pico.t.timer_b_next_oflow>>8);
}
return 0;