From f64c2e710fa1a7b59753224e717f57c48462076f Mon Sep 17 00:00:00 2001
From: Mans Rullgard <mans@mansr.com>
Date: Mon, 12 Dec 2011 00:50:08 +0000
Subject: [PATCH] bswap: make generic implementation more compiler-friendly
With these changes, gcc 4.5 and later recognise it as a bswap
and use the proper instructions on ARM and x86. On x86, the
16-bit bswap is recognised from gcc 4.1.
Signed-off-by: Mans Rullgard <mans@mansr.com>
---
libavutil/arm/bswap.h | 2 ++
libavutil/bswap.h | 13 ++-----------
libavutil/x86/bswap.h | 4 ++++
3 files changed, 8 insertions(+), 11 deletions(-)
diff --git a/libavutil/arm/bswap.h b/libavutil/arm/bswap.h
index 478ae981fba..f94cbcf23ff 100644
--- a/libavutil/arm/bswap.h
+++ b/libavutil/arm/bswap.h
@@ -51,6 +51,7 @@ static av_always_inline av_const unsigned av_bswap16(unsigned x)
}
#endif
+#if !AV_GCC_VERSION_AT_LEAST(4,5)
#define av_bswap32 av_bswap32
static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
{
@@ -66,6 +67,7 @@ static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
#endif /* HAVE_ARMV6 */
return x;
}
+#endif /* !AV_GCC_VERSION_AT_LEAST(4,5) */
#endif /* __ARMCC_VERSION */
diff --git a/libavutil/bswap.h b/libavutil/bswap.h
index 3657ccd402c..8a350e1cd5c 100644
--- a/libavutil/bswap.h
+++ b/libavutil/bswap.h
@@ -65,23 +65,14 @@ static av_always_inline av_const uint16_t av_bswap16(uint16_t x)
#ifndef av_bswap32
static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
{
- x= ((x<<8)&0xFF00FF00) | ((x>>8)&0x00FF00FF);
- x= (x>>16) | (x<<16);
- return x;
+ return AV_BSWAP32C(x);
}
#endif
#ifndef av_bswap64
static inline uint64_t av_const av_bswap64(uint64_t x)
{
- union {
- uint64_t ll;
- uint32_t l[2];
- } w, r;
- w.ll = x;
- r.l[0] = av_bswap32 (w.l[1]);
- r.l[1] = av_bswap32 (w.l[0]);
- return r.ll;
+ return (uint64_t)av_bswap32(x) << 32 | av_bswap32(x >> 32);
}
#endif
diff --git a/libavutil/x86/bswap.h b/libavutil/x86/bswap.h
index b60d9ccd6cf..6840b632cbd 100644
--- a/libavutil/x86/bswap.h
+++ b/libavutil/x86/bswap.h
@@ -28,13 +28,16 @@
#include "config.h"
#include "libavutil/attributes.h"
+#if !AV_GCC_VERSION_AT_LEAST(4,1)
#define av_bswap16 av_bswap16
static av_always_inline av_const unsigned av_bswap16(unsigned x)
{
__asm__("rorw $8, %w0" : "+r"(x));
return x;
}
+#endif /* !AV_GCC_VERSION_AT_LEAST(4,1) */
+#if !AV_GCC_VERSION_AT_LEAST(4,5)
#define av_bswap32 av_bswap32
static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
{
@@ -57,5 +60,6 @@ static inline uint64_t av_const av_bswap64(uint64_t x)
return x;
}
#endif
+#endif /* !AV_GCC_VERSION_AT_LEAST(4,5) */
#endif /* AVUTIL_X86_BSWAP_H */
--
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