FFmpeg/libavutil/arm/intreadwrite.h
Mans Rullgard ababec7b95 arm: intreadwrite: disable inline asm for gcc 4.7 and later
Starting with version 4.7, gcc properly supports unaligned
memory accesses on ARM.  Not using the inline asm with these
compilers results in better code.

Signed-off-by: Mans Rullgard <mans@mansr.com>
2012-05-02 17:26:39 +01:00

86 lines
2.4 KiB
C

/*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_ARM_INTREADWRITE_H
#define AVUTIL_ARM_INTREADWRITE_H
#include <stdint.h>
#include "config.h"
#include "libavutil/attributes.h"
#if HAVE_FAST_UNALIGNED && HAVE_INLINE_ASM && !AV_GCC_VERSION_AT_LEAST(4,7)
#define AV_RN16 AV_RN16
static av_always_inline unsigned AV_RN16(const void *p)
{
const uint8_t *q = p;
unsigned v;
#ifdef __thumb__
__asm__ ("ldrh %0, %1" : "=r"(v) : "m"(q[0]), "m"(q[1]));
#else
__asm__ ("ldrh %0, %1" : "=r"(v) : "Uq"(q[0]), "m"(q[1]));
#endif
return v;
}
#define AV_WN16 AV_WN16
static av_always_inline void AV_WN16(void *p, uint16_t v)
{
__asm__ ("strh %1, %0" : "=m"(*(uint16_t *)p) : "r"(v));
}
#define AV_RN32 AV_RN32
static av_always_inline uint32_t AV_RN32(const void *p)
{
const struct __attribute__((packed)) { uint32_t v; } *q = p;
uint32_t v;
__asm__ ("ldr %0, %1" : "=r"(v) : "m"(*q));
return v;
}
#define AV_WN32 AV_WN32
static av_always_inline void AV_WN32(void *p, uint32_t v)
{
__asm__ ("str %1, %0" : "=m"(*(uint32_t *)p) : "r"(v));
}
#define AV_RN64 AV_RN64
static av_always_inline uint64_t AV_RN64(const void *p)
{
const struct __attribute__((packed)) { uint32_t v; } *q = p;
uint64_t v;
__asm__ ("ldr %Q0, %1 \n\t"
"ldr %R0, %2 \n\t"
: "=&r"(v)
: "m"(q[0]), "m"(q[1]));
return v;
}
#define AV_WN64 AV_WN64
static av_always_inline void AV_WN64(void *p, uint64_t v)
{
__asm__ ("str %Q2, %0 \n\t"
"str %R2, %1 \n\t"
: "=m"(*(uint32_t*)p), "=m"(*((uint32_t*)p+1))
: "r"(v));
}
#endif /* HAVE_INLINE_ASM */
#endif /* AVUTIL_ARM_INTREADWRITE_H */