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dcadsp: scan coefficients linearly in dca_lfe_fir 

This change is inspired by x86 asm where it frees a register.

Signed-off-by: Janne Grunau <janne-libav@jannau.net>
This commit is contained in:
Christophe Gisquet 2014-02-14 15:03:08 +00:00 committed by Janne Grunau
parent ad507d7907
commit 57b1eb9f75
1 changed files with 6 additions and 8 deletions
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14
libavcodec/dcadsp.c
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@ -36,22 +36,20 @@ static inline void
dca_lfe_fir(float *out, const float *in, const float *coefs, dca_lfe_fir(float *out, const float *in, const float *coefs,
int decifactor) int decifactor)
{ {
float *out2 = out + decifactor; float *out2 = out + 2 * decifactor - 1;
const float *cf0 = coefs; int num_coeffs = 256 / decifactor;
const float *cf1 = coefs + 256;
int j, k; int j, k;
/* One decimated sample generates 2*decifactor interpolated ones */ /* One decimated sample generates 2*decifactor interpolated ones */
for (k = 0; k < decifactor; k++) { for (k = 0; k < decifactor; k++) {
float v0 = 0.0; float v0 = 0.0;
float v1 = 0.0; float v1 = 0.0;
for (j = 0; j < 256 / decifactor; j++) { for (j = 0; j < num_coeffs; j++, coefs++) {
float s = in[-j]; v0 += in[-j] * *coefs;
v0 += s * *cf0++; v1 += in[j + 1 - num_coeffs] * *coefs;
v1 += s * *--cf1;
} }
*out++ = v0; *out++ = v0;
*out2++ = v1; *out2-- = v1;
} }
} }