From f79d847400d218cfd0b95f10358fe6e65ec3c9c4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Martin=20Storsj=C3=B6?= Date: Mon, 1 Aug 2016 10:04:42 +0300 Subject: [PATCH] intreadwrite: Use the __unaligned keyword on MSVC for ARM and x86_64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit AV_WN64 is meant for unaligned data, but the existing av_alias* unions (without a definition for the av_alias attribute - we don't have one for MSVC) indicate to the compiler that they would have sufficient alignment for normal access, i.e. the compiler is free to assume 8 byte alignment. On ARM, this makes sure that AV_WN64 (or two consecutive AV_WN32) is done with two str instructions instead of one strd. Signed-off-by: Martin Storsjö --- libavutil/intreadwrite.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/libavutil/intreadwrite.h b/libavutil/intreadwrite.h index 5f65957ce5..32747b21cb 100644 --- a/libavutil/intreadwrite.h +++ b/libavutil/intreadwrite.h @@ -197,6 +197,11 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias; # define AV_RN(s, p) (*((const __unaligned uint##s##_t*)(p))) # define AV_WN(s, p, v) (*((__unaligned uint##s##_t*)(p)) = (v)) +#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_X64)) && AV_HAVE_FAST_UNALIGNED + +# define AV_RN(s, p) (*((const __unaligned uint##s##_t*)(p))) +# define AV_WN(s, p, v) (*((__unaligned uint##s##_t*)(p)) = (v)) + #elif AV_HAVE_FAST_UNALIGNED # define AV_RN(s, p) (((const av_alias##s*)(p))->u##s)