ffmpeg | branch: master | James Darnley <jdarn...@obe.tv> | Sat Feb 11 13:25:09
2017 +0100| [7627df15d411a69f236b4650e88b1ab911f38efc] | committer: James
Darnley
x86util: import MOVHL macro
Originally committed to x264 in 1637239a by Henrik Gramner who has
agreed to re-license it as LGPL. Original commit message follows.
x86: Avoid some bypass delays and false dependencies
A bypass delay of 1-3 clock cycles may occur on some CPUs when transitioning
between int and float domains, so try to avoid that if possible.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7627df15d411a69f236b4650e88b1ab911f38efc
---
libavutil/x86/x86util.asm | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/libavutil/x86/x86util.asm b/libavutil/x86/x86util.asm
index c063436..1408f0a 100644
--- a/libavutil/x86/x86util.asm
+++ b/libavutil/x86/x86util.asm
@@ -876,3 +876,15 @@
psrlq %1, 8*(%2)
%endif
%endmacro
+
+%macro MOVHL 2 ; dst, src
+%ifidn %1, %2
+ punpckhqdq %1, %2
+%elif cpuflag(avx)
+ punpckhqdq %1, %2, %2
+%elif cpuflag(sse4)
+ pshufd %1, %2, q3232 ; pshufd is slow on some older CPUs, so only use
it on more modern ones
+%else
+ movhlps %1, %2 ; may cause an int/float domain transition and
has a dependency on dst
+%endif
+%endmacro
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