Commit Graph

6 Commits

Author SHA1 Message Date
John Koleszar
209d82ad72 Add half-pixel variance RTCD functions
NEON has optimized 16x16 half-pixel variance functions, but they
were not part of the RTCD framework. Add these functions to RTCD,
so that other platforms can make use of this optimization in the
future and special-case ARM code can be removed.

A number of functions were taking two variance functions as
parameters. These functions were changed to take a single
parameter, a pointer to a struct containing all the variance
functions for that block size. This provides additional flexibility
for calling additional variance functions (the half-pixel special
case, for example) and by initializing the table for all block sizes,
we don't have to construct this function pointer table for each
macroblock.

Change-Id: I78289ff36b2715f9a7aa04d5f6fbe3d23acdc29c
2010-10-26 20:00:56 -07:00
Timothy B. Terriberry
b71962fdc9 Add runtime CPU detection support for ARM.
The primary goal is to allow a binary to be built which supports
 NEON, but can fall back to non-NEON routines, since some Android
 devices do not have NEON, even if they are otherwise ARMv7 (e.g.,
 Tegra).
The configure-generated flags HAVE_ARMV7, etc., are used to decide
 which versions of each function to build, and when
 CONFIG_RUNTIME_CPU_DETECT is enabled, the correct version is chosen
 at run time.
In order for this to work, the CFLAGS must be set to something
 appropriate (e.g., without -mfpu=neon for ARMv7, and with
 appropriate -march and -mcpu for even earlier configurations), or
 the native C code will not be able to run.
The ASFLAGS must remain set for the most advanced instruction set
 required at build time, since the ARM assembler will refuse to emit
 them otherwise.
I have not attempted to make any changes to configure to do this
 automatically.
Doing so will probably require the addition of new configure options.

Many of the hooks for RTCD on ARM were already there, but a lot of
 the code had bit-rotted, and a good deal of the ARM-specific code
 is not integrated into the RTCD structs at all.
I did not try to resolve the latter, merely to add the minimal amount
 of protection around them to allow RTCD to work.
Those functions that were called based on an ifdef at the calling
 site were expanded to check the RTCD flags at that site, but they
 should be added to an RTCD struct somewhere in the future.
The functions invoked with global function pointers still are, but
 these should be moved into an RTCD struct for thread safety (I
 believe every platform currently supported has atomic pointer
 stores, but this is not guaranteed).

The encoder's boolhuff functions did not even have _c and armv7
 suffixes, and the correct version was resolved at link time.
The token packing functions did have appropriate suffixes, but the
 version was selected with a define, with no associated RTCD struct.
However, for both of these, the only armv7 instruction they actually
 used was rbit, and this was completely superfluous, so I reworked
 them to avoid it.
The only non-ARMv4 instruction remaining in them is clz, which is
 ARMv5 (not even ARMv5TE is required).
Considering that there are no ARM-specific configs which are not at
 least ARMv5TE, I did not try to detect these at runtime, and simply
 enable them for ARMv5 and above.

Finally, the NEON register saving code was completely non-reentrant,
 since it saved the registers to a global, static variable.
I moved the storage for this onto the stack.
A single binary built with this code was tested on an ARM11 (ARMv6)
 and a Cortex A8 (ARMv7 w/NEON), for both the encoder and decoder,
 and produced identical output, while using the correct accelerated
 functions on each.
I did not test on any earlier processors.

Change-Id: I45cbd63a614f4554c3b325c45d46c0806f009eaa
2010-10-25 09:23:29 -04:00
John Koleszar
c2140b8af1 Use WebM in copyright notice for consistency
Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.

Fixes issue #97.

Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
2010-09-09 10:01:21 -04:00
John Koleszar
94c52e4da8 cosmetics: trim trailing whitespace
When the license headers were updated, they accidentally contained
trailing whitespace, so unfortunately we have to touch all the files
again.

Change-Id: I236c05fade06589e417179c0444cb39b09e4200d
2010-06-18 13:06:11 -04:00
John Koleszar
09202d8071 LICENSE: update with latest text
Change-Id: Ieebea089095d9073b3a94932791099f614ce120c
2010-06-04 16:19:40 -04:00
John Koleszar
0ea50ce9cb Initial WebM release 2010-05-18 11:58:33 -04:00