FYI,
I forgot to comment in the commit message:
I kept the original code for 64 bit because while using r2b works in 64
bits, using it severely hurt performance to the point that it was well
below c code.
This is probably due to how things like instruction order, length and
layout in memory can affect performance(see agner docs).
This probably leaves some room for performance improvements since most
X265 assembler is based primarily on algorithms implementing x265
functionality but not all aspects of processor function. While writing
optimized assembler for every processor is unrealistic, the assembler of
each simd level could be optimized for the latest processor that
supports it.(i.e. the sse4 assembler could be optimized to support the
latest processor that support only up to sse4).
One downside is these types of optimizations are more likely to generate
code that looks like the jumbled code generated by a compiler and thus
be less easy to read, understand and maintain. Of course more comments
can help here.
Is x265 interested in such optimizations?
On 02/25/2015 08:31 PM, Deepthi Nandakumar wrote:
Thanks, pushed.
On Thu, Feb 26, 2015 at 8:03 AM, <[email protected]
<mailto:[email protected]>> wrote:
# HG changeset patch
# User David T Yuen <[email protected] <mailto:[email protected]>>
# Date 1424917924 28800
# Node ID 13346cb90bff040492f0688226f44182bb6b97d8
# Parent 74c716607444c77b9d5ea1dce5b99c875f0b20fe
Fixed 32 bit bug in intrapred dc4 sse2
Changed register written from to one that supports low byte access
in 32 bit
Also moved pw_257 constant to const-a.asm
diff -r 74c716607444 -r 13346cb90bff source/common/x86/const-a.asm
--- a/source/common/x86/const-a.asm Tue Feb 24 13:39:16 2015 +0530
+++ b/source/common/x86/const-a.asm Wed Feb 25 18:32:04 2015 -0800
@@ -37,6 +37,7 @@
const pw_32, times 16 dw 32
const pw_128, times 16 dw 128
const pw_256, times 16 dw 256
+const pw_257, times 16 dw 257
const pw_512, times 16 dw 512
const pw_1023, times 8 dw 1023
const pw_1024, times 16 dw 1024
diff -r 74c716607444 -r 13346cb90bff source/common/x86/intrapred8.asm
--- a/source/common/x86/intrapred8.asm Tue Feb 24 13:39:16 2015 +0530
+++ b/source/common/x86/intrapred8.asm Wed Feb 25 18:32:04 2015 -0800
@@ -65,8 +65,6 @@
pw_planar32_L: dw 31, 30, 29, 28, 27, 26, 25, 24
pw_planar32_H: dw 23, 22, 21, 20, 19, 18, 17, 16
-pw_257: times 8 dw 257
-
const ang_table
%assign x 0
%rep 32
@@ -80,6 +78,7 @@
cextern pw_8
cextern pw_16
cextern pw_32
+cextern pw_257
cextern pw_1024
cextern pb_unpackbd1
cextern multiL
@@ -144,12 +143,21 @@
paddw m2, m1
psraw m2, 2
packuswb m2, m2
+%if ARCH_X86_64
movq r4, m2
mov [r0], r4b
shr r4, 8
mov [r0 + r1], r4b
shr r4, 8
mov [r0 + r1 * 2], r4b
+%else
+ movd r2d, m2
+ mov [r0], r2b
+ shr r2, 8
+ mov [r0 + r1], r2b
+ shr r2, 8
+ mov [r0 + r1 * 2], r2b
+%endif
.end:
RET
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