diff options
| author | Roland Scheidegger <rscheidegger_lists@hispeed.ch> | 2012-04-20 02:10:57 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2012-04-21 00:27:06 +0200 |
| commit | a812b599b504b39a8021827da89d5e23fb361cc9 (patch) | |
| tree | 34b3f8ce41b8cdca8df4f3b84682731b09c94f34 /libavcodec/h264_cabac.c | |
| parent | 3194ab78a6c4ea0a4c60c91c4d0ea34028ca408f (diff) | |
h264: assembly version of get_cabac for x86_64 with PIC (v4)
This adds a hand-optimized assembly version for get_cabac much like the
existing one, but it works if the table offsets are RIP-relative.
Compared to the non-RIP-relative version this adds 2 lea instructions
and it needs one extra register.
There is a surprisingly large performance improvement over the c version (more
so than the generated assembly seems to suggest) just in get_cabac, I measured
roughly 40% faster for get_cabac on a K8. However, overall the difference is
not that big, I measured roughly 5% on a test clip on a K8 and a Core2.
Hopefully it still compiles on x86 32bit...
v2: incorporated feedback from Loren Merritt to avoid rip-relative movs
for every table, and got rid of unnecessary @GOTPCREL.
v3: apply similar fixes to the the decode_significance functions, and use
same macro arguments for non-pic case.
v4: prettify inline asm arguments, add a non-fast-cmov version (as I expect
the c code to be faster otherwise since both cmov and sbb suck hard on a
Prescott, even can't construct the mask with a 64bit shift as that's just as
terrible - it's quite difficult to find usable instructions on that chip...).
This is tested to work but not on a P4, in theory it _should_ be fast there.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavcodec/h264_cabac.c')
| -rw-r--r-- | libavcodec/h264_cabac.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/libavcodec/h264_cabac.c b/libavcodec/h264_cabac.c index 65f2cb4dc8..6c59d174a2 100644 --- a/libavcodec/h264_cabac.c +++ b/libavcodec/h264_cabac.c @@ -1659,7 +1659,7 @@ decode_cabac_residual_internal(H264Context *h, DCTELEM *block, index[coeff_count++] = last;\ } const uint8_t *sig_off = significant_coeff_flag_offset_8x8[MB_FIELD]; -#if ARCH_X86 && HAVE_7REGS && !defined(BROKEN_RELOCATIONS) +#if ARCH_X86 && HAVE_7REGS coeff_count= decode_significance_8x8_x86(CC, significant_coeff_ctx_base, index, last_coeff_ctx_base, sig_off); } else { |