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vorbisdec: replace div/mod in loop with a counter

2x speedup of surround decoding on Cortex-A9.

Signed-off-by: Mans Rullgard <mans@mansr.com>
tags/n1.0
Mans Rullgard 13 years ago
parent
commit
9fcda25e35
1 changed files with 12 additions and 5 deletions
  1. +12
    -5
      libavcodec/vorbisdec.c

+ 12
- 5
libavcodec/vorbisdec.c View File

@@ -1409,17 +1409,24 @@ static av_always_inline int vorbis_residue_decode_internal(vorbis_context *vc,
}

} else if (vr_type == 2) {
voffs = voffset;
unsigned voffs_div = FASTDIV(voffset, ch);
unsigned voffs_mod = voffset - voffs_div * ch;

for (k = 0; k < step; ++k) {
coffs = get_vlc2(gb, codebook.vlc.table, codebook.nb_bits, 3) * dim;
for (l = 0; l < dim; ++l, ++voffs) {
vec[voffs / ch + (voffs % ch) * vlen] += codebook.codevectors[coffs + l]; // FPMATH FIXME use if and counter instead of / and %
for (l = 0; l < dim; ++l) {
vec[voffs_div + voffs_mod * vlen] +=
codebook.codevectors[coffs + l];

av_dlog(NULL, " pass %d offs: %d curr: %f change: %f cv offs.: %d+%d \n",
pass, voffset / ch + (voffs % ch) * vlen,
vec[voffset / ch + (voffs % ch) * vlen],
pass, voffs_div + voffs_mod * vlen,
vec[voffs_div + voffs_mod * vlen],
codebook.codevectors[coffs + l], coffs, l);

if (++voffs_mod == ch) {
voffs_div++;
voffs_mod = 0;
}
}
}
}


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