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Cleanups

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This commit is contained in:
twinaphex 2020-10-07 01:04:34 +02:00
parent 16a7bbe0ab
commit 22e75e22c2
1 changed files with 46 additions and 107 deletions
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153
neopopsound.c
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@ -77,121 +77,62 @@ static _u32 UpdateStep = 0; /* Number of steps during one sample. */
static _u16 sample_chip_tone(void)
{
int i;
int i;
int vol[3];
unsigned int out;
int vol[3];
unsigned int out;
int left;
/* vol[] keeps track of how long each square wave stays */
/* in the 1 position during the sample period. */
vol[0] = vol[1] = vol[2] = /*vol[3] = */ 0;
/* vol[] keeps track of how long each square wave stays */
/* in the 1 position during the sample period. */
vol[0] = vol[1] = vol[2] = /*vol[3] = */ 0;
for (i = 0; i < 3; i++)
{
if (toneChip.Output[i]) vol[i] += toneChip.Count[i];
toneChip.Count[i] -= STEP;
for (i = 0; i < 3; i++)
{
if (toneChip.Output[i]) vol[i] += toneChip.Count[i];
toneChip.Count[i] -= STEP;
/* Period[i] is the half period of the square wave. Here, in each */
/* loop I add Period[i] twice, so that at the end of the loop the */
/* square wave is in the same status (0 or 1) it was at the start. */
/* vol[i] is also incremented by Period[i], since the wave has been 1 */
/* exactly half of the time, regardless of the initial position. */
/* If we exit the loop in the middle, Output[i] has to be inverted */
/* and vol[i] incremented only if the exit status of the square */
/* wave is 1. */
/* Period[i] is the half period of the square wave. Here, in each */
/* loop I add Period[i] twice, so that at the end of the loop the */
/* square wave is in the same status (0 or 1) it was at the start. */
/* vol[i] is also incremented by Period[i], since the wave has been 1 */
/* exactly half of the time, regardless of the initial position. */
/* If we exit the loop in the middle, Output[i] has to be inverted */
/* and vol[i] incremented only if the exit status of the square */
/* wave is 1. */
while (toneChip.Count[i] <= 0)
{
toneChip.Count[i] += toneChip.Period[i];
if (toneChip.Count[i] > 0)
{
toneChip.Output[i] ^= 1;
if (toneChip.Output[i]) vol[i] += toneChip.Period[i];
break;
}
toneChip.Count[i] += toneChip.Period[i];
vol[i] += toneChip.Period[i];
}
if (toneChip.Output[i]) vol[i] -= toneChip.Count[i];
}
while (toneChip.Count[i] <= 0)
{
toneChip.Count[i] += toneChip.Period[i];
if (toneChip.Count[i] > 0)
{
toneChip.Output[i] ^= 1;
if (toneChip.Output[i]) vol[i] += toneChip.Period[i];
break;
}
toneChip.Count[i] += toneChip.Period[i];
vol[i] += toneChip.Period[i];
}
if (toneChip.Output[i]) vol[i] -= toneChip.Count[i];
}
/*
left = STEP;
do
{
int nextevent;
out = vol[0] * toneChip.Volume[0] + vol[1] * toneChip.Volume[1] +
vol[2] * toneChip.Volume[2];
if (toneChip.Count[3] < left) nextevent = toneChip.Count[3];
else nextevent = left;
if (toneChip.Output[3]) vol[3] += toneChip.Count[3];
toneChip.Count[3] -= nextevent;
if (toneChip.Count[3] <= 0)
{
if (toneChip.RNG & 1) toneChip.RNG ^= toneChip.NoiseFB;
toneChip.RNG >>= 1;
toneChip.Output[3] = toneChip.RNG & 1;
toneChip.Count[3] += toneChip.Period[3];
if (toneChip.Output[3]) vol[3] += toneChip.Period[3];
}
if (toneChip.Output[3]) vol[3] -= toneChip.Count[3];
left -= nextevent;
} while (left > 0);
*/
out = vol[0] * toneChip.Volume[0] + vol[1] * toneChip.Volume[1] +
vol[2] * toneChip.Volume[2];
if (out > MAX_OUTPUT_STEP)
if (out > MAX_OUTPUT_STEP)
out = MAX_OUTPUT_STEP;
return out>>STEP_SHIFT;
return out>>STEP_SHIFT;
}
/* ============================================================================= */
static _u16 sample_chip_noise(void)
{
int i;
int vol3 = 0;
unsigned int out;
int left;
/* vol[] keeps track of how long each square wave stays */
/* in the 1 position during the sample period. */
/*
vol[0] = vol[1] = vol[2] = vol[3] = 0;
for (i = 0; i < 3; i++)
{
if (noiseChip.Output[i]) vol[i] += noiseChip.Count[i];
noiseChip.Count[i] -= STEP;
// Period[i] is the half period of the square wave. Here, in each
// loop I add Period[i] twice, so that at the end of the loop the
// square wave is in the same status (0 or 1) it was at the start.
// vol[i] is also incremented by Period[i], since the wave has been 1
// exactly half of the time, regardless of the initial position.
// If we exit the loop in the middle, Output[i] has to be inverted
// and vol[i] incremented only if the exit status of the square
// wave is 1.
while (noiseChip.Count[i] <= 0)
{
noiseChip.Count[i] += noiseChip.Period[i];
if (noiseChip.Count[i] > 0)
{
noiseChip.Output[i] ^= 1;
if (noiseChip.Output[i]) vol[i] += noiseChip.Period[i];
break;
}
noiseChip.Count[i] += noiseChip.Period[i];
vol[i] += noiseChip.Period[i];
}
if (noiseChip.Output[i]) vol[i] -= noiseChip.Count[i];
}
*/
if (noiseChip.Volume[3])
{
left = STEP;
@ -199,24 +140,21 @@ static _u16 sample_chip_noise(void)
{
int nextevent = min(noiseChip.Count[3],left);
#if 0
if (noiseChip.Count[3] < left)
nextevent = noiseChip.Count[3];
else
nextevent = left;
#endif
if (noiseChip.Output[3]) vol3 += noiseChip.Count[3];
if (noiseChip.Output[3])
vol3 += noiseChip.Count[3];
noiseChip.Count[3] -= nextevent;
if (noiseChip.Count[3] <= 0)
{
if (noiseChip.RNG & 1) noiseChip.RNG ^= noiseChip.NoiseFB;
if (noiseChip.RNG & 1)
noiseChip.RNG ^= noiseChip.NoiseFB;
noiseChip.RNG >>= 1;
noiseChip.Output[3] = noiseChip.RNG & 1;
noiseChip.Count[3] += noiseChip.Period[3];
if (noiseChip.Output[3]) vol3 += noiseChip.Period[3];
if (noiseChip.Output[3])
vol3 += noiseChip.Period[3];
}
if (noiseChip.Output[3]) vol3 -= noiseChip.Count[3];
if (noiseChip.Output[3])
vol3 -= noiseChip.Count[3];
left -= nextevent;
} while (left > 0);
@ -263,7 +201,8 @@ void WriteSoundChip(SoundChip* chip, _u8 data)
case 2: /* tone 1 : frequency */
case 4: /* tone 2 : frequency */
chip->Period[c] = UpdateStep * chip->Register[r];
if (chip->Period[c] == 0) chip->Period[c] = UpdateStep;
if (chip->Period[c] == 0)
chip->Period[c] = UpdateStep;
if (r == 4)
{
/* update noise shift frequency */