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Syntrax/Jaytrax: Replace cubic interpolation function with a fixed point integer based version, for a 20% performance boost

CQTexperiment
Christopher Snowhill 2021-12-24 23:33:34 -08:00
parent a8a982d3a4
commit d4614a2f03
1 changed files with 4 additions and 3 deletions
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7
Frameworks/Syntrax-c/Syntrax-c/mixcore.c
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@ -7,6 +7,7 @@
// ITP_[number of taps]_[input sample width]_[fractional precision]_[readable name]
#define ITP_T02_S16_I08_LINEAR(P, F) (P[0]+(((P[1]-P[0])*F) >> 8))
#define ITP_T03_S16_I15_QUADRA(P, F) (((((((((P[0] + P[2]) >> 1) - P[1]) * F) >> 16) + P[1]) - ((P[2] + P[0] + (P[0] << 1)) >> 2)) * F) >> 14) + P[0]
#define ITP_T04_S16_I08_CUBIC(P, F) (P[1] + ((F*(P[2] - P[0] + ((F*(2 * P[0] - 5 * P[1] + 4 * P[2] - P[3] + ((F*(3 * (P[1] - P[2]) + P[3] - P[0]) + 0x80) >> 8)) + 0x80) >> 8)) + 0x100) >> 9))
#define ITP_T04_SXX_F01_CUBIC(P, F) (P[1] + 0.5 * F*(P[2] - P[0] + F*(2.0 * P[0] - 5.0 * P[1] + 4.0 * P[2] - P[3] + F * (3.0 * (P[1] - P[2]) + P[3] - P[0]))))
@ -44,14 +45,14 @@ static int32_t itpQuad(int16_t* buf, int32_t pos, int32_t sizeMask) {
static int32_t itpCubic(int16_t* buf, int32_t pos, int32_t sizeMask) {
int32_t p[4];
float frac = (float)(pos & 0xFF)/256;
int32_t frac = pos & 0xFF;
p[0] = GET_PT(0);
p[1] = GET_PT(1);
p[2] = GET_PT(2);
p[3] = GET_PT(3);
return ITP_T04_SXX_F01_CUBIC(p, frac);
return ITP_T04_S16_I08_CUBIC(p, frac);
}
Interpolator interps[INTERP_COUNT] = {
@ -209,4 +210,4 @@ void jaymix_mixCore(JT1Player* SELF, int32_t numSamples) {
outBuf[off + BUF_ECHOR] += (samp * vc->gainEchoR)>>8;
}
}
}
}