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Remove costly memory reads/writes in vp8_reset_mb_tokens_context()

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Tests on x86 showed this function costed 2.7% of total decoding time
because of all the memory reads/writes. After modification, it only
costs about 0.7% of decoding time, which gives a 2% gain.

Change-Id: I5003ee30b6dc6dea0bfa42a6ad7e7c22fcc7b215
This commit is contained in:
Yunqing Wang 2010-05-28 14:34:39 -04:00 committed by John Koleszar
parent 1689564bb5
commit d33bf3d664
1 changed files with 30 additions and 11 deletions
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41
vp8/decoder/detokenize.c
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@ -67,23 +67,42 @@ void vp8_reset_mb_tokens_context(MACROBLOCKD *x)
ENTROPY_CONTEXT *l;
int i;
for (i = 0; i < 24; i++)
{
/* Clear entropy contexts for Y blocks */
a = A[Y1CONTEXT];
l = L[Y1CONTEXT];
*a = 0;
*(a+1) = 0;
*(a+2) = 0;
*(a+3) = 0;
*l = 0;
*(l+1) = 0;
*(l+2) = 0;
*(l+3) = 0;
a = A[ vp8_block2context[i] ] + vp8_block2above[i];
l = L[ vp8_block2context[i] ] + vp8_block2left[i];
/* Clear entropy contexts for U blocks */
a = A[UCONTEXT];
l = L[UCONTEXT];
*a = 0;
*(a+1) = 0;
*l = 0;
*(l+1) = 0;
*a = *l = 0;
}
/* Clear entropy contexts for V blocks */
a = A[VCONTEXT];
l = L[VCONTEXT];
*a = 0;
*(a+1) = 0;
*l = 0;
*(l+1) = 0;
/* Clear entropy contexts for Y2 blocks */
if (x->mbmi.mode != B_PRED && x->mbmi.mode != SPLITMV)
{
a = A[Y2CONTEXT] + vp8_block2above[24];
l = L[Y2CONTEXT] + vp8_block2left[24];
*a = *l = 0;
a = A[Y2CONTEXT];
l = L[Y2CONTEXT];
*a = 0;
*l = 0;
}
}
DECLARE_ALIGNED(16, extern const unsigned int, vp8dx_bitreader_norm[256]);
#define NORMALIZE \