Diego Biurrun <[email protected]> writes:

> On Sat, May 14, 2011 at 09:41:01AM +0100, Måns Rullgård wrote:
>> Justin Ruggles <[email protected]> writes:
>> 
>> > This does all the actual bit counting as a final step.
>> > x86 benchmarks:
>> > 50% faster in function count_mantissa_bits()
>> > 16% faster in function bit_alloc()
>> > ---
>> >  libavcodec/ac3dsp.c              |   33 ++++++++--------
>> >  libavcodec/ac3dsp.h              |    4 +-
>> >  libavcodec/ac3enc.c              |   78 
>> > +++++++++++++++++++++-----------------
>> >  libavcodec/arm/Makefile          |    1 -
>> >  libavcodec/arm/ac3dsp_arm.S      |   52 -------------------------
>> >  libavcodec/arm/ac3dsp_init_arm.c |    2 -
>> >  6 files changed, 63 insertions(+), 107 deletions(-)
>> >  delete mode 100644 libavcodec/arm/ac3dsp_arm.S
>> > +static void count_mantissa_bits_update_ch(AC3EncodeContext *s, int ch,
>> > +                                          uint16_t 
>> > mant_cnt[AC3_MAX_BLOCKS][16],
>> > +                                          int start, int end)
>> > +{
>> > +    int blk, i;
>> > +
>> > +    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
>> > +        uint8_t *bap = s->blocks[blk].exp_ref_block[ch]->bap[ch];
>> > +        for (i = start; i < end; i++)
>> > +            mant_cnt[blk][bap[i]]++;
>> 
>> This loop will suck with gcc on ARM.
>
> I'm curious as to why, could you elaborate?

Because gcc sucks, what else?  This particular suckage was the main
reason for writing that function assembler at all.

-- 
Måns Rullgård
[email protected]
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