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sound, fix ym2612 ladder effect, add option

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This commit is contained in:
kub 2021-11-19 21:01:50 +01:00
parent b55e4e1b2f
commit 23cd73bc8f
9 changed files with 46 additions and 22 deletions
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20
pico/sound/ym2612.c
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@ -922,7 +922,8 @@ typedef struct
static int clip(int n)
{
unsigned b = 14, s = n < 0;
if (s + (n>>(b-1))) n = (int)(s + INT_MAX) >> (8*sizeof(int)-b);
int m = s + INT_MAX;
if (s + (n>>(b-1))) n = m >> (8*sizeof(int)-b);
return n;
}
@ -1234,7 +1235,11 @@ static void chan_render_loop(chan_rend_context *ct, int *buffer, int length)
/* mix sample to output buffer */
if (smp) {
smp = clip(smp); /* saturate to 14 bit */
smp = clip(smp); /* saturate to 14 bit */
if (ct->algo & 0x80) {
smp &= ~0x1f; /* drop bits (DAC has 9 bits) */
smp -= (smp < 0 ? 7:0) << 5; /* discontinuity */
}
if (ct->pack & 1) { /* stereo */
if (ct->pack & 0x20) /* L */ /* TODO: check correctness */
buffer[scounter*2] += smp;
@ -1271,15 +1276,6 @@ static void chan_render_finish(int *buffer, unsigned short length, int active_ch
ym2612.OPN.eg_timer = crct.eg_timer;
g_lfo_ampm = crct.pack >> 16; // need_save
ym2612.OPN.lfo_cnt = crct.lfo_cnt;
/* apply ladder effect. NB only works if buffer was empty beforehand! */
if (active_chans && (ym2612.OPN.ST.flags & ST_LADDER)) {
length <<= crct.pack & 1;
while (length--) {
*buffer -= (*buffer < 0)*4 << 5;
buffer++;
}
}
}
static UINT32 update_lfo_phase(FM_SLOT *SLOT, UINT32 block_fnum)
@ -1339,6 +1335,8 @@ static int chan_render(int *buffer, int length, int c, UINT32 flags) // flags: s
crct.op1_out = crct.CH->op1_out;
crct.algo = crct.CH->ALGO & 7;
if (ym2612.OPN.ST.flags & ST_DAC)
crct.algo |= 0x80;
if(crct.CH->pms && (ym2612.OPN.ST.mode & 0xC0) && c == 2) {
/* 3 slot mode */