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5e27ca23
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2025-09-19T14:21:49
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x86: Reformat NASM code to improve readability
(and simplify the checkstyle script)
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7e45654c
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2024-03-04T18:10:16
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Merge branch 'main' into dev
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3202feb0
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2024-02-29T16:10:20
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x86-64 SIMD: Support CET if C compiler enables it
- Detect at configure time, via the __CET__ C preprocessor macro,
whether the C compiler will include either indirect branch tracking
(IBT) or shadow stack support, and define a NASM macro (__CET__) if
so.
- Modify the x86-64 SIMD code so that it includes appropriate endbr64
instructions (to support IBT) and an appropriate .note.gnu.property
section (to support both IBT and shadow stack) when __CET__ is
defined.
Closes #350
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13355475
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2024-02-29T12:18:49
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x86 SIMD: Capitalize all instruction-like macros
(to improve code readability)
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e69dd40c
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2024-01-23T13:26:41
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Reorganize source to make things easier to find
- Move all libjpeg documentation, except for README.ijg, into the doc/
subdirectory.
- Move the TurboJPEG C API documentation from doc/html/ into
doc/turbojpeg/.
- Move all C source code and headers into a src/ subdirectory.
- Move turbojpeg-jni.c into the java/ subdirectory.
Referring to #226, there is no ideal solution to this problem. A
semantically ideal solution would have involved placing all source code,
including the SIMD and Java source code, under src/ (or perhaps placing
C library source code under lib/ and C test program source code under
test/), all header files under include/, and all documentation under
doc/. However:
- To me it makes more sense to have separate top-level directories for
each language, since the SIMD extensions and the Java API are
technically optional features. src/ now contains only the code that
is relevant to the core C API libraries and associated programs.
- I didn't want to bury the java/ and simd/ directories or add a level
of depth to them, since both directories already contain source code
that is 3-4 levels deep.
- I would prefer not to separate the header files from the C source
code, because:
1. It would be disruptive. libjpeg and libjpeg-turbo have
historically placed C source code and headers in the same
directory, and people who are familiar with both projects (self
included) are used to looking for the headers in the same directory
as the C source code.
2. In terms of how the headers are used internally in libjpeg-turbo,
the distinction between public and private headers is a bit fuzzy.
- It didn't make sense to separate the test source code from the library
source code, since there is not a clear distinction in some cases.
(For instance, the IJG image I/O functions are used by cjpeg and djpeg
as well as by the TurboJPEG API.)
This solution is minimally disruptive, since it keeps all C source code
and headers together and keeps java/ and simd/ as top-level directories.
It is a bit awkward, because java/ and simd/ technically contain source
code, even though they are not under src/. However, other solutions
would have been more awkward for different reasons.
Closes #226
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7b844bfd
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2023-07-28T11:46:10
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x86-64 SIMD: Use std stack frame/prologue/epilogue
This allows debuggers and profilers to reliably capture backtraces from
within the x86-64 SIMD functions.
In places where rbp was previously used to access temporary variables
(after stack alignment), we now use r15 and save/restore it accordingly.
The total amount of work is approximately the same, because the previous
code pushed the pre-alignment stack pointer to the aligned stack. The
new prologue and epilogue actually have fewer instructions.
Also note that the {un}collect_args macros now use rbp instead of rax to
access arguments passed on the stack, so we save a few instructions
there as well.
Based on:
https://github.com/alk/libjpeg-turbo/commit/debcc7c3b436467aea8d02c66a514c5099d0ad37
Closes #707
Closes #708
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cd342acf
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2020-10-27T16:42:14
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Merge branch 'master' into dev
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d27b935a
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2020-10-27T15:04:39
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Consistify formatting to simplify checkstyle
The checkstyle script was hastily developed prior to libjpeg-turbo 2.0
beta1, so it has a lot of exceptions and is thus prone to false
negatives. This commit eliminates some of those exceptions.
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f60b6dd3
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2019-11-12T17:42:39
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Remove vestigial jpeg_nbits_table.inc
Not needed since 087c29e07f7533ec82fd7eb1dafc84c29e7870ec
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bbedb4b5
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2019-11-05T15:43:21
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Merge branch 'master' into dev
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cf54623b
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2019-11-05T12:21:25
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Mac: Support hiding SIMD fct symbols w/ NASM 2.14+
(NASM 2.14+ now supports the private_extern section directive, which was
previously only available with YASM.)
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087c29e0
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2018-10-22T10:05:18
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Optimize Huffman encoding
This commit improves the C and SSE2 Huffman encoding implementations in
the following ways:
- Avoid using xmm8-xmm15 in the x86-64 SSE2 implementation. There is no
actual need to use those registers, and avoiding them produces a
cleaner WIN64 function entry/exit-- as well as shorter code, since REX
prefixes can be avoided (this is helpful on certain CPUs, such as
Intel Atom, for which instruction fetch and decoding can be a
bottleneck.)
- Optimize register usage so that fewer REX prefixes and
register-register moves are needed.
- Use the bit counter to store the number of free bits in the bit buffer
rather than the number of bits in the bit buffer. This changes the
method for inserting a code into the bit buffer to:
(put_buffer |= code << (free_bits -= code_size));
As a result:
* Only one bit counter needs to stay in a register (we just keep it in
cl.)
* The bit buffer contents are already properly aligned to be written
out (after a byte swap.)
* Adjusting the free bits counter and checking if the bit buffer is
full can be combined into a single operation.
* We can wait to flush the bit buffer until the buffer is actually
full and not just in danger of becoming full. Thus, eight bytes can
be flushed at a time.
- Speed is quite sensitive to the alignment of branch target labels, so
insert some padding and remove branches from the flush code.
(Flushing this way isn't actually faster when compared to using
branches, but the branchless code doesn't need extra alignment and is
thus smaller.)
- Speculatively write out the bit buffer as a single 8-byte write,
falling back to a byte-by-byte write only if there are any 0xFF bytes
in the bit buffer that need to be encoded as 0xFF 0x00.
- Use MMX registers for the 32-bit implementation (so the bit buffer can
be 64 bits wide.)
- Slightly reduce overall function code size.
- Eliminate or combine a few SSE instructions.
- Make some minor improvements to instruction scheduling.
- Adjust flush_bits() in jchuff.c to handle cases in which the bit
buffer has less than 7 free bits (apparently that couldn't happen
before.)
Based on:
https://github.com/1camper/libjpeg-turbo/commit/947a09defa2ec848322b1bae050d1b57b316a32a
https://github.com/1camper/libjpeg-turbo/commit/262ebb6b816fd8a49ff4d7185f6c5153dddde02f
https://github.com/1camper/libjpeg-turbo/commit/6e9a091221bb244c8ba232a942650e94254ffcf0
See change log for performance claims.
Closes #292
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95f4d6ef
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2019-10-24T02:13:23
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Merge branch 'master' into dev
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3a32d199
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2019-10-17T19:59:01
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x86 SIMD: Consistify capitalization of NASM types
byte, word, dword, qword, oword, and yword are all assembler keywords,
so it makes sense to use lowercase for these so as not to mistake them
for macros or constants.
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9a51a87a
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2019-10-17T11:21:32
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x86 SIMD: Remove obsolete [TAB8] comments
With apologies to Richard Hendricks, our assembly code no longer uses
tabs.
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133e4af0
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2018-09-04T16:56:22
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Add x32 ABI support on Linux
The x32 ABI is similar to the x86-64 ABI but uses 32-bit pointers.
(Refer to https://sites.google.com/site/x32abi)
Based on:
https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/8da8fc5213d87336d6c7200aaeeca925603e12cf
https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/1e33dfea8042230e266b453f53d69a6e37b7f0de
https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/24ffea78da0f18d0d467d16e02dfb903e6c0181e
https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/dedcf76753c8913ef5c3c6e4ea329d29494b6065
https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/d04228a7b58b9aed5bcbec383630ec1a14a3c9ca
https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/b4ad38316ae1899c8a00b6568bb0325d82edcd7a
Closes #274
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bfc3ce31
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2018-04-10T15:50:22
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x86[-64] SIMD: Don't auto-generate jsimdcfg.inc
The old Un*x (autotools-based) build system always auto-generated this
file, but that behavior was more or less a relic of the days before the
libjpeg-turbo colorspace extensions were implemented. The thinking was
that, if a particular developer wanted to change RGB_RED, RGB_GREEN,
RGB_BLUE, or RGB_PIXELSIZE in order to compress from/decompress to
different RGB pixel layouts, then the SIMD extensions should
automatically respond to those changes whenever they were made to
jmorecfg.h. The modern reality is that changing RGB_* is no longer
necessary because of the libjpeg-turbo colorspace extensions, and
changing any of the other constants in jsimdcfg.inc can't be done
without making deeper modifications to the SIMD extensions. In general,
we treat RGB_* as a de facto, immutable part of the legacy libpjeg API.
Realistically, since the values of those constants have been the same in
every Un*x distribution released in the past 20-30 years, any software
that uses a system-supplied build of libjpeg must assume that those
constants will have default values.
Furthermore, even if it made sense to auto-generate jsimdcfg.inc, it was
never possible to do so on Windows, so it was always going to be
necessary to manually generate the Windows version of the file whenever
any of the constants changed. This commit introduces a new custom CMake
target called "jsimdcfg" that can be used, on Un*x platforms, to
generate jsimdcfg.inc on demand, although this should only be necessary
when introducing new x86 SIMD instructions or making other deep
modifications, such as SIMD acceleration for 12-bit JPEGs.
For those who may be wondering why we don't do the same thing for
win/jconfig.h.in, it's because performing all of the necessary CMake
checks to populate that file is very slow on Windows.
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293263c3
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2018-03-17T15:14:35
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Format preprocessor macros more consistently
Within the libjpeg API code, it seems to be more the convention than not
to separate the macro name and value by two or more spaces, which
improves general readability. Making this consistent across all of
libjpeg-turbo is less about my individual preferences and more about
making it easy to automatically detect variations from our chosen
formatting convention. I intend to release the script I'm using to
validate this stuff, once it matures and stabilizes a bit.
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19c791cd
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2018-03-08T10:55:20
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Improve code formatting consistency
With rare exceptions ...
- Always separate line continuation characters by one space from
preceding code.
- Always use two-space indentation. Never use tabs.
- Always use K&R-style conditional blocks.
- Always surround operators with spaces, except in raw assembly code.
- Always put a space after, but not before, a comma.
- Never put a space between type casts and variables/function calls.
- Never put a space between the function name and the argument list in
function declarations and prototypes.
- Always surround braces ('{' and '}') with spaces.
- Always surround statements (if, for, else, catch, while, do, switch)
with spaces.
- Always attach pointer symbols ('*' and '**') to the variable or
function name.
- Always precede pointer symbols ('*' and '**') by a space in type
casts.
- Use the MIN() macro from jpegint.h within the libjpeg and TurboJPEG
API libraries (using min() from tjutil.h is still necessary for
TJBench.)
- Where it makes sense (particularly in the TurboJPEG code), put a blank
line after variable declaration blocks.
- Always separate statements in one-liners by two spaces.
The purpose of this was to ease maintenance on my part and also to make
it easier for contributors to figure out how to format patch
submissions. This was admittedly confusing (even to me sometimes) when
we had 3 or 4 different style conventions in the same source tree. The
new convention is more consistent with the formatting of other OSS code
bases.
This commit corrects deviations from the chosen formatting style in the
libjpeg API code and reformats the TurboJPEG API code such that it
conforms to the same standard.
NOTES:
- Although it is no longer necessary for the function name in function
declarations to begin in Column 1 (this was historically necessary
because of the ansi2knr utility, which allowed libjpeg to be built
with non-ANSI compilers), we retain that formatting for the libjpeg
code because it improves readability when using libjpeg's function
attribute macros (GLOBAL(), etc.)
- This reformatting project was accomplished with the help of AStyle and
Uncrustify, although neither was completely up to the task, and thus
a great deal of manual tweaking was required. Note to developers of
code formatting utilities: the libjpeg-turbo code base is an
excellent test bed, because AFAICT, it breaks every single one of the
utilities that are currently available.
- The legacy (MMX, SSE, 3DNow!) assembly code for i386 has been
formatted to match the SSE2 code (refer to
ff5685d5344273df321eb63a005eaae19d2496e3.) I hadn't intended to
bother with this, but the Loongson MMI implementation demonstrated
that there is still academic value to the MMX implementation, as an
algorithmic model for other 64-bit vector implementations. Thus, it
is desirable to improve its readability in the same manner as that of
the SSE2 implementation.
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367a8386
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2018-02-26T19:41:59
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Make SIMD syms private for x86[-64]/Mach-O builds
... if building with YASM. NASM doesn't currently support the necessary
directives.
Closes #212
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7c2bfdb0
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2018-02-26T18:43:40
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Merge branch 'master' into dev
Closes #214
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88421563
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2018-02-23T21:56:32
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Make SIMD symbols private for x86[-64] ELF builds
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ff392d81
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2018-02-17T17:29:38
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AVX2: Introduce YMMBLOCK macro for readability
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6abd3916
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2016-11-15T08:47:43
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Unified CMake-based build system
See #56 for discussion.
Fixes #21, Fixes #29, Fixes #37, Closes #56, Fixes #58, Closes #73
Obviates #82
See also:
https://sourceforge.net/p/libjpeg-turbo/feature-requests/5/
https://sourceforge.net/p/libjpeg-turbo/patches/5/
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