resample: add some float math optimization

Multiplying and adding the smaller floats first will reduce the amount
of rounding errors.
This commit is contained in:
Wim Taymans 2021-10-18 21:17:36 +02:00
parent cc996b6292
commit 67209b9ecc

View file

@ -87,10 +87,15 @@ static void inner_product_c(float *d, const float * SPA_RESTRICT s,
const float * SPA_RESTRICT taps, uint32_t n_taps)
{
float sum = 0.0f;
#if 1
uint32_t i, j, nt2 = n_taps/2;
for (i = 0, j = n_taps-1; i < nt2; i++, j--)
sum += s[i] * taps[i] + s[j] * taps[j];
#else
uint32_t i;
for (i = 0; i < n_taps; i++)
sum += s[i] * taps[i];
#endif
*d = sum;
}
@ -100,11 +105,18 @@ static void inner_product_ip_c(float *d, const float * SPA_RESTRICT s,
{
float sum[2] = { 0.0f, 0.0f };
uint32_t i;
#if 1
uint32_t j, nt2 = n_taps/2;
for (i = 0, j = n_taps-1; i < nt2; i++, j--) {
sum[0] += s[i] * t0[i] + s[j] * t0[j];
sum[1] += s[i] * t1[i] + s[j] * t1[j];
}
#else
for (i = 0; i < n_taps; i++) {
sum[0] += s[i] * t0[i];
sum[1] += s[i] * t1[i];
}
#endif
*d = (sum[1] - sum[0]) * x + sum[0];
}