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Use pmovmskb to skip quantize loops over empty coefficients.

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If none of the 16 coefficients that we quantize per loop iteration
are larger than the zbin, directly skip to the next round of coeffs,
rather than doing a full quantize loop that will eventually result
in 16 zeroes. This incurs a jump cost, but saves a lot of other work.
32x32 quant goes from 1349 -> 1184 cycles. The same approach yielded
no significantly positive results for smaller transforms, so is not
used there (8x8: 103 -> 101 cycles; 16x16: 302 -> 306 cycles).

Change-Id: I8fca17dc2543fc8eed1dbcd5100145e3c3a9b647
This commit is contained in:
Ronald S. Bultje 2013-07-01 12:03:20 -07:00
parent 5b87240230
commit e5fb4b61b6
1 changed files with 25 additions and 9 deletions
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34
vp9/encoder/x86/vp9_quantize_ssse3.asm
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@ -15,10 +15,10 @@ pw_1: times 8 dw 1
SECTION .text
%macro QUANTIZE_FN 1
cglobal quantize_%1, 0, 6, 15, coeff, ncoeff, skip, zbin, round, quant, \
shift, qcoeff, dqcoeff, dequant, zbin_oq, \
eob, scan, iscan
%macro QUANTIZE_FN 2
cglobal quantize_%1, 0, %2, 15, coeff, ncoeff, skip, zbin, round, quant, \
shift, qcoeff, dqcoeff, dequant, zbin_oq, \
eob, scan, iscan
cmp dword skipm, 0
jne .blank
@ -43,9 +43,8 @@ cglobal quantize_%1, 0, 6, 15, coeff, ncoeff, skip, zbin, round, quant, \
mova m4, [r2] ; m4 = shift
mov r4, dqcoeffmp
mov r5, iscanmp
mov r2, eobmp
pxor m5, m5 ; m5 = dedicated zero
DEFINE_ARGS coeff, ncoeff, eob, qcoeff, dqcoeff, iscan
DEFINE_ARGS coeff, ncoeff, d1, qcoeff, dqcoeff, iscan, d2, d3, d4, d5, d6, eob
lea coeffq, [ coeffq+ncoeffq*2]
lea iscanq, [ iscanq+ncoeffq*2]
lea qcoeffq, [ qcoeffq+ncoeffq*2]
@ -119,6 +118,12 @@ cglobal quantize_%1, 0, 6, 15, coeff, ncoeff, skip, zbin, round, quant, \
%endif
pcmpgtw m7, m6, m0 ; m7 = c[i] >= zbin
pcmpgtw m12, m11, m0 ; m12 = c[i] >= zbin
%ifidn %1, b_32x32
pmovmskb r6, m7
pmovmskb r2, m12
or r6, r2
jz .skip_iter
%endif
paddw m6, m1 ; m6 += round
paddw m11, m1 ; m11 += round
pmulhw m14, m6, m2 ; m14 = m6*q>>16
@ -159,16 +164,27 @@ cglobal quantize_%1, 0, 6, 15, coeff, ncoeff, skip, zbin, round, quant, \
pmaxsw m8, m13
add ncoeffq, mmsize
jl .ac_only_loop
%ifidn %1, b_32x32
jmp .accumulate_eob
.skip_iter:
mova [qcoeffq+ncoeffq*2+ 0], m5
mova [qcoeffq+ncoeffq*2+16], m5
mova [dqcoeffq+ncoeffq*2+ 0], m5
mova [dqcoeffq+ncoeffq*2+16], m5
add ncoeffq, mmsize
jl .ac_only_loop
%endif
.accumulate_eob:
; horizontally accumulate/max eobs and write into [eob] memory pointer
mov r2, eobmp
pshufd m7, m8, 0xe
pmaxsw m8, m7
pshuflw m7, m8, 0xe
pmaxsw m8, m7
pshuflw m7, m8, 0x1
pmaxsw m8, m7
pextrw [eobq], m8, 0
pextrw [r2], m8, 0
RET
; skip-block, i.e. just write all zeroes
@ -194,5 +210,5 @@ cglobal quantize_%1, 0, 6, 15, coeff, ncoeff, skip, zbin, round, quant, \
%endmacro
INIT_XMM ssse3
QUANTIZE_FN b
QUANTIZE_FN b_32x32
QUANTIZE_FN b, 6
QUANTIZE_FN b_32x32, 7