From f4ac80227b4efbe1ed839dd5782feed0ec89a03f Mon Sep 17 00:00:00 2001 From: Christophe Gisquet Date: Sat, 6 Apr 2013 10:52:12 +0000 Subject: sbrdsp: unroll sbr_autocorrelate_c 1410 cycles to 1148 on Arrandale/Win64. Signed-off-by: Michael Niedermayer --- libavcodec/sbrdsp.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'libavcodec/sbrdsp.c') diff --git a/libavcodec/sbrdsp.c b/libavcodec/sbrdsp.c index 6fede79..e2280cc 100644 --- a/libavcodec/sbrdsp.c +++ b/libavcodec/sbrdsp.c @@ -122,9 +122,34 @@ static av_always_inline void autocorrelate(const float x[40][2], static void sbr_autocorrelate_c(const float x[40][2], float phi[3][2][2]) { +#if 0 + // This code is slower because it multiplies memory accesses. + // It is left as eucational purpose and because it may offer + // a better reference for writing arch-specific dsp functions. autocorrelate(x, phi, 0); autocorrelate(x, phi, 1); autocorrelate(x, phi, 2); +#else + float real_sum2 = x[ 0][0] * x[ 2][0] + x[ 0][1] * x[ 2][1]; + float imag_sum2 = x[ 0][0] * x[ 2][1] - x[ 0][1] * x[ 2][0]; + float real_sum1 = 0.f, imag_sum1 = 0.f, real_sum0 = 0.0f; + int i; + for (i = 1; i < 38; i++) { + real_sum0 += x[i][0] * x[i ][0] + x[i][1] * x[i ][1]; + real_sum1 += x[i][0] * x[i+1][0] + x[i][1] * x[i+1][1]; + imag_sum1 += x[i][0] * x[i+1][1] - x[i][1] * x[i+1][0]; + real_sum2 += x[i][0] * x[i+2][0] + x[i][1] * x[i+2][1]; + imag_sum2 += x[i][0] * x[i+2][1] - x[i][1] * x[i+2][0]; + } + phi[2-2][1][0] = real_sum2; + phi[2-2][1][1] = imag_sum2; + phi[2 ][1][0] = real_sum0 + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1]; + phi[1 ][0][0] = real_sum0 + x[38][0] * x[38][0] + x[38][1] * x[38][1]; + phi[2-1][1][0] = real_sum1 + x[ 0][0] * x[ 1][0] + x[ 0][1] * x[ 1][1]; + phi[2-1][1][1] = imag_sum1 + x[ 0][0] * x[ 1][1] - x[ 0][1] * x[ 1][0]; + phi[0 ][0][0] = real_sum1 + x[38][0] * x[39][0] + x[38][1] * x[39][1]; + phi[0 ][0][1] = imag_sum1 + x[38][0] * x[39][1] - x[38][1] * x[39][0]; +#endif } static void sbr_hf_gen_c(float (*X_high)[2], const float (*X_low)[2], -- cgit v1.1