Commit e5fb4b61 authored by Ronald S. Bultje's avatar Ronald S. Bultje

Use pmovmskb to skip quantize loops over empty coefficients.

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
parent 5b872402
......@@ -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
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