PPC is normally big endian but has special little endian load/store
instructions. Using these avoids a separate byteswap. This makes the
vorbis decoder about 5% faster. Not much else uses little-endian
read/write extensively.
GCC generates horrible PPC code for the default AV_[RW]B64 (which uses
a packed struct), so we override it with a plain pointer cast.
Originally committed as revision 18602 to svn://svn.ffmpeg.org/ffmpeg/trunk
ARMv6 and later support unaligned loads and stores for single
word/halfword but not double/multiple. GCC is ignorant of this and
will always use bytewise accesses for unaligned data. Casting to an
int32_t pointer is dangerous since a load/store double or multiple
instruction might be used (this happens with some code in FFmpeg).
Implementing the AV_[RW]* macros with inline asm using only supported
instructions gives fast and safe unaligned accesses. ARM RVCT does
the right thing with generic code.
This gives an overall speedup of up to 10%.
Originally committed as revision 18601 to svn://svn.ffmpeg.org/ffmpeg/trunk
This changes intreadwrite.h to support per-arch implementations of the
various macros allowing us to take advantage of special instructions
or other properties the compiler does not know about.
Originally committed as revision 18600 to svn://svn.ffmpeg.org/ffmpeg/trunk
Consistently apply this rule: the guard name is obtained from the
filename by stripping the leading "lib", converting '/' and '.' to
'_' and uppercasing the resulting name. Guard names in the root
directory have to be prefixed by "FFMPEG_".
Originally committed as revision 15120 to svn://svn.ffmpeg.org/ffmpeg/trunk
Patch by Jindrich Makovicka, makovick at gmail dot com
Reference thread:
Subject: Re: [PATCH] make libavcodec use bytestream functions
Date: Thu, 10 May 2007 07:49:43 +0200
Originally committed as revision 8982 to svn://svn.ffmpeg.org/ffmpeg/trunk
patch by Ramiro Polla ramiro lisha ufsc br
original thread:
date: 03/11/2007 03:06 AM
subject: [Ffmpeg-devel] [PATCH] Machine endian bytestream functions
Originally committed as revision 8803 to svn://svn.ffmpeg.org/ffmpeg/trunk
optimization/cleanup would be desirable (e.g. LE_* and LD*
should be the same on x86).
Originally committed as revision 7218 to svn://svn.ffmpeg.org/ffmpeg/trunk
