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Speed up MIDI by 20% on Pico with faster SADD #791

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Speed up MIDI by 20% on Pico with faster SADD #791

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2 changes: 1 addition & 1 deletion lib/TinySoundFont
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Submodule TinySoundFont updated 1 files
+19 −9 tsf.h
28 changes: 19 additions & 9 deletions src/libtinysoundfont/tsf.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1632,9 +1632,9 @@ static void tsf_voice_render_short(tsf* f, struct tsf_voice* v, short* outputBuf
// // Simple linear interpolation.
// float alpha = (float)(tmpSourceSamplePosition - pos), val = (input[pos] * (1.0f - alpha) + input[nextPos] * alpha);
#ifdef ESP8266
fixed16p16 val = pgm_read_word(&input[pos >> 8]);
int16_t val = pgm_read_word(&input[pos >> 8]);
#else
fixed16p16 val = input[pos >> 8];
int16_t val = input[pos >> 8];
#endif

// Low-pass filter.
Expand All @@ -1645,16 +1645,26 @@ static void tsf_voice_render_short(tsf* f, struct tsf_voice* v, short* outputBuf

smp = *outL;
smp += (val * gainLeftF16P16) >> 16;
if (smp > 32767) smp = 32767;
else if (smp < -32768) smp = -32768;
*outL++ = smp;
// We checn for OVF by verifying that all the bits in the upper half-word are the same. If they're not then we ovf'd pos or neg
int16_t ovf = smp >> 16;
if ((ovf == 0) || (ovf == -1)) {
*outL++ = smp;
} else if (ovf < 0) {
*outL++ = -32768;
} else {
*outL++ = 32767;
}

smp = *outL;
smp += (val * gainRightF16P16) >> 16;
if (smp > 32767) smp = 32767;
else if (smp < -32768) smp = -32768;
*outL++ = smp;

int16_t ovfr = smp >> 16;
if ((ovfr == 0) || (ovfr == -1)) {
*outL++ = smp;
} else if (ovfr < 0) {
*outL++ = -32768;
} else {
*outL++ = 32767;
}

// *outL++ += val * gainLeft;
// *outL++ += val * gainRight;
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