[FFmpeg-devel] [PATCH 10/10] lavc/flacenc: partially unroll loop in flac_enc_lpc_32
James Darnley
james.darnley at gmail.com
Wed Feb 12 00:11:22 CET 2014
Now does 6 samples per iteration, up from 2.
>From 1.6 to 2.1 times faster again. 2.5 to 3.9 times faster overall.
Runtime is reduced by a further 4 to 17%. Reduced by 9 to 65% overall.
Same conditions as previously.
---
libavcodec/x86/flac_dsp_gpl.asm | 30 +++++++++++++++++++++++++++---
1 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/libavcodec/x86/flac_dsp_gpl.asm b/libavcodec/x86/flac_dsp_gpl.asm
index e36c76b..704e461 100644
--- a/libavcodec/x86/flac_dsp_gpl.asm
+++ b/libavcodec/x86/flac_dsp_gpl.asm
@@ -157,15 +157,25 @@ mova [rsp], m4 ; sign extend mask
.looplen:
pxor m0, m0
+ pxor m4, m4
+ pxor m6, m6
xor posj, posj
xor negj, negj
.looporder:
movd m2, [coefsq+posj*4] ; c = coefs[j]
SPLATD m2
movh m1, [smpq+negj*4-4] ; s = smp[i-j-1]
+ movh m5, [smpq+negj*4-4+mmsize/2]
+ movh m7, [smpq+negj*4-4+mmsize]
pshufd m1, m1, q3130
+ pshufd m5, m5, q3130
+ pshufd m7, m7, q3130
pmuldq m1, m2
+ pmuldq m5, m2
+ pmuldq m7, m2
paddq m0, m1 ; p += c * s
+ paddq m4, m5
+ paddq m6, m7
add posj, 1
sub negj, 1
@@ -175,14 +185,28 @@ mova [rsp], m4 ; sign extend mask
pxor m2, m2
HACK_PSRAQ m0, m3, [rsp], m2
+ pxor m2, m2
+ HACK_PSRAQ m4, m3, [rsp], m2
+ pxor m2, m2
+ HACK_PSRAQ m6, m3, [rsp], m2
CLIPQ m0, [pq_int_min], [pq_int_max], m2
+ CLIPQ m4, [pq_int_min], [pq_int_max], m2
+ CLIPQ m6, [pq_int_min], [pq_int_max], m2
pshufd m0, m0, q0020 ; pack into first 2 dwords
+ pshufd m4, m4, q0020
+ pshufd m6, m6, q0020
movh m1, [smpq]
+ movh m5, [smpq+mmsize/2]
+ movh m7, [smpq+mmsize]
psubd m1, m0 ; smp[i] - p
+ psubd m5, m4
+ psubd m7, m6
movh [resq], m1 ; res[i] = smp[i] - (p >> shift)
+ movh [resq+mmsize/2], m5
+ movh [resq+mmsize], m7
- add resq, mmsize/2
- add smpq, mmsize/2
- sub lenmp, mmsize/8
+ add resq, (3*mmsize)/2
+ add smpq, (3*mmsize)/2
+ sub lenmp, (3*mmsize)/8
jg .looplen
RET
--
1.7.9
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