av_bswapXX() are used in context that expect exact size types, notably
variable arguments to av_log(). On Linux RV64, uint_fast32_t is an
unsigned long, so the current inline assembler does not work properly.
Since GCC and Clang gained their byte-swap built-ins before they
supported RISC-V, we can simply defer to them. As an added bonus, the
compiler can do instruction scheduling, which it couldn't with the Zbb
inline assembler.
If the target supports the Basic bit-manipulation (Zbb) extension, then
the REV8 instruction is available to reverse byte order.
Note that this instruction only exists at the "XLEN" register size,
so we need to right shift the result down to the data width.
If Zbb is not supported, then this patchset does nothing. Support for
run-time detection is left for the future. Currently, there are no
bits in auxv/ELF HWCAP for Z-extensions, so there are no clean ways to
do this.
There are no particular reasons to force the compiler to use the same
register as output and input operand. This forces an extra MOV
instruction if the input value needs to be reused after the swap.
In most cases, this makes no differences, as the compiler will seleect
the same register for both operands either way.
Signed-off-by: Martin Storsjö <martin@martin.st>
This reduces the number of false dependencies on header files and
speeds up compilation.
Originally committed as revision 22407 to svn://svn.ffmpeg.org/ffmpeg/trunk
Otherwise doxygen complains about ambiguous filenames when files exist
under the same name in different subdirectories.
Originally committed as revision 16912 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
while playing with some new hardware, I found it's running a forked mplayer
-- and it looks like they're following the GPL.
The maintainer's page is here: http://atty.jp/?Zaurus/mplayer
Unfortunately it's mostly in Japanese, so it's hard to figure out any
details.
Their code looks quite interesting (at least to those of us w/ ARM CPUs).
The patches I've attached are the patches from atty.jp with a couple of
modifications by myself:
- ported to current CVS
- reverted their change of removing SNOW support from ffmpeg
- cleaned up their bswap mess
- removed DOS-style linebreaks from various files
patch by (Bernhard Rosenkraenzer: bero, arklinux org)
Originally committed as revision 4311 to svn://svn.ffmpeg.org/ffmpeg/trunk
Rémi Denis-Courmont
Janne Grunau
Mans Rullgard
Diego Biurrun
Stefano Sabatini
Aurelien Jacobs
Luca Barbato
Michael Niedermayer
Bernhard Rosenkränzer
Zdenek Kabelac
Fabrice Bellard