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core, implement GG stereo

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This commit is contained in:
kub 2024-01-21 21:41:31 +01:00
parent fa4e0531d4
commit 70efc52db8
9 changed files with 112 additions and 80 deletions
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40
pico/sound/sn76496.c
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@ -56,7 +56,7 @@ struct SN76496
int Period[4];
int Count[4];
int Output[4];
int pad[1];
int Panning;
};
static struct SN76496 ono_sn; // one and only SN76496
@ -135,7 +135,6 @@ void SN76496Update(short *buffer, int length, int stereo)
while (length > 0)
{
int vol[4];
unsigned int out;
int left;
@ -203,19 +202,43 @@ void SN76496Update(short *buffer, int length, int stereo)
} while (left > 0 && R->Volume[3]);
if (R->Output[3]) vol[3] -= R->Count[3];
out = vol[0] * R->Volume[0] + vol[1] * R->Volume[1] +
length--;
if (R->Panning == 0xff || !stereo) {
unsigned int out =
vol[0] * R->Volume[0] + vol[1] * R->Volume[1] +
vol[2] * R->Volume[2] + vol[3] * R->Volume[3];
if (out > MAX_OUTPUT * STEP) out = MAX_OUTPUT * STEP;
if (out > MAX_OUTPUT * STEP) out = MAX_OUTPUT * STEP;
out /= STEP; // will be optimized to shift; max 0x4800 = 18432
*buffer++ += out;
if (stereo) *buffer++ += out;
out /= STEP; // will be optimized to shift; max 0x4800 = 18432
*buffer++ += out;
if (stereo) *buffer++ += out;
} else {
#define P(n) !!(R->Panning & (1<<(n)))
unsigned int outl =
vol[0] * R->Volume[0] * P(4) + vol[1] * R->Volume[1] * P(5) +
vol[2] * R->Volume[2] * P(6) + vol[3] * R->Volume[3] * P(7);
unsigned int outr =
vol[0] * R->Volume[0] * P(0) + vol[1] * R->Volume[1] * P(1) +
vol[2] * R->Volume[2] * P(2) + vol[3] * R->Volume[3] * P(3);
#undef P
if (outl > MAX_OUTPUT * STEP) outl = MAX_OUTPUT * STEP;
if (outr > MAX_OUTPUT * STEP) outr = MAX_OUTPUT * STEP;
length--;
outl /= STEP; // will be optimized to shift; max 0x4800 = 18432
outr /= STEP; // will be optimized to shift; max 0x4800 = 18432
*buffer++ += outl;
*buffer++ += outr;
}
}
}
void SN76496Config(int panning)
{
struct SN76496 *R = &ono_sn;
R->Panning = panning & 0xff;
}
static void SN76496_set_clock(struct SN76496 *R,int clock)
{
@ -286,6 +309,7 @@ int SN76496_init(int clock,int sample_rate)
// added
SN76496_set_gain(R, 0);
R->Panning = 0xff;
return 0;
}