[FFmpeg-devel] [PATCH 2/5] DCA: use a local variable for loop boundary
Kostya
kostya.shishkov
Mon Apr 12 05:34:02 CEST 2010
On Sun, Apr 11, 2010 at 11:05:51PM +0100, Mans Rullgard wrote:
> This prevents gcc reloading the value from memory on each iteration
> of the loop.
> ---
> libavcodec/dca.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/libavcodec/dca.c b/libavcodec/dca.c
> index 596756c..7a6841d 100644
> --- a/libavcodec/dca.c
> +++ b/libavcodec/dca.c
> @@ -757,6 +757,7 @@ static void qmf_32_subbands(DCAContext * s, int chans,
> const float *prCoeff;
> int i;
>
> + int sb_act = s->subband_activity[chans];
> int subindex;
>
> scale *= sqrt(1/8.0);
> @@ -770,7 +771,7 @@ static void qmf_32_subbands(DCAContext * s, int chans,
> /* Reconstructed channel sample index */
> for (subindex = 0; subindex < 8; subindex++) {
> /* Load in one sample from each subband and clear inactive subbands */
> - for (i = 0; i < s->subband_activity[chans]; i++){
> + for (i = 0; i < sb_act; i++){
> uint32_t v = AV_RN32A(&samples_in[i][subindex]) ^ ((i-1)&2)<<30;
> AV_WN32A(&s->raXin[i], v);
> }
looks ok
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