[FFmpeg-devel] [PATCH] NEON: put_pixels_clamped

David Conrad lessen42
Thu Apr 16 21:56:25 CEST 2009


On Apr 16, 2009, at 3:44 PM, David Conrad wrote:

> On Apr 16, 2009, at 3:32 PM, M?ns Rullg?rd wrote:
>
>> David Conrad <lessen42 at gmail.com> writes:
>>
>>> Hi,
>>>
>>> Apparently this is used for some wmv3 files in addition to the  
>>> signed
>>> variant.
>>> < 1% faster decode.
>>>
>>>
>>> commit 38cac0d21d8308e077bb762d712ab7c19e8c826d
>>> Author: David Conrad <davedc at Kozue.local>
>>> Date:   Thu Apr 16 14:30:29 2009 -0400
>>>
>>>   NEON: put_pixels_clamped
>>>
>>> diff --git a/libavcodec/arm/dsputil_neon.c b/libavcodec/arm/ 
>>> dsputil_neon.c
>>> index 37425a3..9b95130 100644
>>> --- a/libavcodec/arm/dsputil_neon.c
>>> +++ b/libavcodec/arm/dsputil_neon.c
>>> @@ -42,6 +42,7 @@ void ff_put_pixels8_xy2_no_rnd_neon(uint8_t *,  
>>> const uint8_t *, int, int);
>>> void ff_avg_pixels16_neon(uint8_t *, const uint8_t *, int, int);
>>>
>>> void ff_add_pixels_clamped_neon(const DCTELEM *, uint8_t *, int);
>>> +void ff_put_pixels_clamped_neon(const DCTELEM *, uint8_t *, int);
>>> void ff_put_signed_pixels_clamped_neon(const DCTELEM *, uint8_t *,  
>>> int);
>>>
>>> void ff_put_h264_qpel16_mc00_neon(uint8_t *, uint8_t *, int);
>>> @@ -180,6 +181,7 @@ void ff_dsputil_init_neon(DSPContext *c,  
>>> AVCodecContext *avctx)
>>>    c->avg_pixels_tab[0][0] = ff_avg_pixels16_neon;
>>>
>>>    c->add_pixels_clamped = ff_add_pixels_clamped_neon;
>>> +    c->put_pixels_clamped = ff_put_pixels_clamped_neon;
>>>    c->put_signed_pixels_clamped = ff_put_signed_pixels_clamped_neon;
>>>
>>>    c->put_h264_chroma_pixels_tab[0] = ff_put_h264_chroma_mc8_neon;
>>> diff --git a/libavcodec/arm/dsputil_neon_s.S b/libavcodec/arm/ 
>>> dsputil_neon_s.S
>>> index f16293d..159ee64 100644
>>> --- a/libavcodec/arm/dsputil_neon_s.S
>>> +++ b/libavcodec/arm/dsputil_neon_s.S
>>> @@ -273,6 +273,30 @@ function ff_put_h264_qpel8_mc00_neon, export=1
>>>        pixfunc2 put_ pixels8_y2,   _no_rnd, vhadd.u8
>>>        pixfunc2 put_ pixels8_xy2,  _no_rnd, vshrn.u16, 1
>>>
>>> +function ff_put_pixels_clamped_neon, export=1
>>> +        vld1.64         {d16-d19}, [r0,:128]!
>>> +        vqmovn.u16      d0, q8
>>> +        vld1.64         {d20-d23}, [r0,:128]!
>>> +        vqmovn.u16      d1, q9
>>> +        vqmovn.u16      d2, q10
>>> +        vld1.64         {d24-d27}, [r0,:128]!
>>> +        vqmovn.u16      d3, q11
>>> +        vqmovn.u16      d4, q12
>>> +        vld1.64         {d28-d31}, [r0,:128]!
>>> +        vqmovn.u16      d5, q13
>>> +        vqmovn.u16      d6, q14
>>> +        vst1.64         {d0},      [r1,:64], r2
>>> +        vqmovn.u16      d7, q15
>>> +        vst1.64         {d1},      [r1,:64], r2
>>> +        vst1.64         {d2},      [r1,:64], r2
>>> +        vst1.64         {d3},      [r1,:64], r2
>>> +        vst1.64         {d4},      [r1,:64], r2
>>> +        vst1.64         {d5},      [r1,:64], r2
>>> +        vst1.64         {d6},      [r1,:64], r2
>>> +        vst1.64         {d7},      [r1,:64], r2
>>> +        bx              lr
>>> +        .endfunc
>>
>> Shouldn't those be vqmovun.s16?  I'd also try to interleave them with
>> the loads and stores a bit more for better dual-issue opportunities.
>
> Unsigned pixels; MMX does the same (packuswb for put_pixels_clamped  
> vs. packsswb for put_signed_pixels_clamped)

Oops, you're right, I didn't read packuswb. New patch attached.

> Also, the loads take two issue cycles since they're loading 4  
> registers; shouldn't they be able to dual issue on both cycles?


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