From 7627df15d411a69f236b4650e88b1ab911f38efc Mon Sep 17 00:00:00 2001 From: James Darnley Date: Sat, 11 Feb 2017 13:25:09 +0100 Subject: [PATCH] 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. --- libavutil/x86/x86util.asm | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/libavutil/x86/x86util.asm b/libavutil/x86/x86util.asm index c063436e0a..1408f0a176 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 -- 2.11.0