Module: libav Branch: master Commit: dabf8dd34afdbb6dc9dc7603d7a5228fc67de4c8
Author: Christophe GISQUET <[email protected]> Committer: Ronald S. Bultje <[email protected]> Date: Wed Feb 22 17:48:59 2012 +0100 SBR DSP: unroll sum_square The length is even, so some unrolling can be performed. Timings are for x86: - 32bits: 102c -> 82c - 64bits: 82c -> 69c Signed-off-by: Ronald S. Bultje <[email protected]> --- libavcodec/sbrdsp.c | 13 +++++++++---- 1 files changed, 9 insertions(+), 4 deletions(-) diff --git a/libavcodec/sbrdsp.c b/libavcodec/sbrdsp.c index f942759..8c88fb3 100644 --- a/libavcodec/sbrdsp.c +++ b/libavcodec/sbrdsp.c @@ -35,13 +35,18 @@ static void sbr_sum64x5_c(float *z) static float sbr_sum_square_c(float (*x)[2], int n) { - float sum = 0.0f; + float sum0 = 0.0f, sum1 = 0.0f; int i; - for (i = 0; i < n; i++) - sum += x[i][0] * x[i][0] + x[i][1] * x[i][1]; + for (i = 0; i < n; i += 2) + { + sum0 += x[i + 0][0] * x[i + 0][0]; + sum1 += x[i + 0][1] * x[i + 0][1]; + sum0 += x[i + 1][0] * x[i + 1][0]; + sum1 += x[i + 1][1] * x[i + 1][1]; + } - return sum; + return sum0 + sum1; } static void sbr_neg_odd_64_c(float *x) _______________________________________________ libav-commits mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-commits
