kmx git

Commit	Date	Message
5e27ca23	2025-09-19T14:21:49	x86: Reformat NASM code to improve readability (and simplify the checkstyle script)
4e151a4a	2025-08-26T21:11:07	Remove vestigial filenames from SIMD code headers These were a relic of libjpeg/SIMD, which attempted to follow the conventions of the libjpeg source code, but they are no longer relevant (or even accurate in some cases.)
eb753630	2024-08-31T16:50:08	Update URLs - Eliminate unnecessary "www." - Use HTTPS. - Update Java, MSYS, tdm-gcc, and NSIS URLs. - Update URL and title of Agner Fog's assembly language optimization manual. - Remove extraneous information about MASM and Borland Turbo Assembler and outdated NASM URLs from the x86 assembly headers, and mention Yasm.
13355475	2024-02-29T12:18:49	x86 SIMD: Capitalize all instruction-like macros (to improve code readability)
fa2b6ea0	2024-01-12T18:21:41	Eliminate duplicate copies of jpeg_nbits_table ef9a4e05ba919494cbebe50e15f332de5ab97e82 (libjpeg-turbo 1.4.x), which was based on https://bug815473.bmoattachments.org/attachment.cgi?id=692126 (https://bugzilla.mozilla.org/show_bug.cgi?id=815473), modified the C baseline Huffman encoder so that it precomputes jpeg_nbits_table, in order to facilitate sharing the table among multiple processes. However, libjpeg-turbo never shared the table, and because the table was implemented as a static array, f3a8684cd1c28e557d394470962a7a224c76ddbc (libjpeg-turbo 1.5.x) and 37bae1a0e977ee1ba769e6f0aa27e519ab6e58c6 (libjpeg-turbo 2.0.x) each introduced a duplicate copy of the table for (respectively) the SSE2 baseline Huffman encoder and the C progressive Huffman encoder. This commit does the following: - Move the duplicated code in jchuff.c and jcphuff.c, originally introduced in 0cfc4c17b740cb2cbb11f9d85c8ab3745d5b913a and 37bae1a0e977ee1ba769e6f0aa27e519ab6e58c6, into a header (jpeg_nbits.h). - Credit the co-author of 0cfc4c17b740cb2cbb11f9d85c8ab3745d5b913a. (Refer to https://sourceforge.net/p/libjpeg-turbo/patches/57). - Modify the SSE2 baseline Huffman encoder so that the C Huffman encoders can share its definition of jpeg_nbits_table. - Move the definition of jpeg_nbits_table into a C source file (jpeg_nbits.c) rather than a header, and define the table only if USE_CLZ_INTRINSIC is undefined and the SSE2 baseline Huffman encoder will not be built. - Apply hidden symbol visibility to the shared definition of jpeg_nbits_table, if the compiler supports the necessary attribute. (In practice, only Visual C++ doesn't.) Closes #114 See also: https://bugzilla.mozilla.org/show_bug.cgi?id=1501523
9c6f79e9	2019-11-13T14:36:37	Fix formatting issues detected by checkstyle
cbf0fcc8	2019-11-05T11:56:06	i386 SSE2 Huffman: Fix pointer arithmetic issue Splitting the pointer arithmetic in GET_SYM() into a separate add and sub instruction was an attempt to work around an error ("invalid operand type") that occurred when assembling the file with NASM. However, this created a link error on macOS ("ld: illegal text-relocation to '_jconst_huff_encode_one_block' in simd/CMakeFiles/simd.dir/i386/jchuff-sse2.asm.o from '_jsimd_huff_encode_one_block_sse2' in simd/CMakeFiles/simd.dir/i386/jchuff-sse2.asm.o for architecture i386") and also changed the alignment of the code in ways that might have affected the previous benchmark results (which took a great deal of time to obtain.) Ultimately, the path of least resistance is just to require NASM 2.13 or later.
087c29e0	2018-10-22T10:05:18	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
3a32d199	2019-10-17T19:59:01	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.
9a51a87a	2019-10-17T11:21:32	x86 SIMD: Remove obsolete [TAB8] comments With apologies to Richard Hendricks, our assembly code no longer uses tabs.
81baa1b5	2018-03-21T13:03:30	simd/i386/jchuff-sse2.asm: Minor formatting tweak
19c791cd	2018-03-08T10:55:20	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.
88421563	2018-02-23T21:56:32	Make SIMD symbols private for x86[-64] ELF builds
c0f3512d	2017-08-31T20:57:19	Merge branch 'master' into dev
6abd3916	2016-11-15T08:47:43	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/

5e27ca23

2025-09-19T14:21:49

x86: Reformat NASM code to improve readability (and simplify the checkstyle script)

4e151a4a

2025-08-26T21:11:07

Remove vestigial filenames from SIMD code headers These were a relic of libjpeg/SIMD, which attempted to follow the conventions of the libjpeg source code, but they are no longer relevant (or even accurate in some cases.)

eb753630

2024-08-31T16:50:08

Update URLs - Eliminate unnecessary "www." - Use HTTPS. - Update Java, MSYS, tdm-gcc, and NSIS URLs. - Update URL and title of Agner Fog's assembly language optimization manual. - Remove extraneous information about MASM and Borland Turbo Assembler and outdated NASM URLs from the x86 assembly headers, and mention Yasm.

13355475

2024-02-29T12:18:49

x86 SIMD: Capitalize all instruction-like macros (to improve code readability)

fa2b6ea0

2024-01-12T18:21:41

Eliminate duplicate copies of jpeg_nbits_table ef9a4e05ba919494cbebe50e15f332de5ab97e82 (libjpeg-turbo 1.4.x), which was based on https://bug815473.bmoattachments.org/attachment.cgi?id=692126 (https://bugzilla.mozilla.org/show_bug.cgi?id=815473), modified the C baseline Huffman encoder so that it precomputes jpeg_nbits_table, in order to facilitate sharing the table among multiple processes. However, libjpeg-turbo never shared the table, and because the table was implemented as a static array, f3a8684cd1c28e557d394470962a7a224c76ddbc (libjpeg-turbo 1.5.x) and 37bae1a0e977ee1ba769e6f0aa27e519ab6e58c6 (libjpeg-turbo 2.0.x) each introduced a duplicate copy of the table for (respectively) the SSE2 baseline Huffman encoder and the C progressive Huffman encoder. This commit does the following: - Move the duplicated code in jchuff.c and jcphuff.c, originally introduced in 0cfc4c17b740cb2cbb11f9d85c8ab3745d5b913a and 37bae1a0e977ee1ba769e6f0aa27e519ab6e58c6, into a header (jpeg_nbits.h). - Credit the co-author of 0cfc4c17b740cb2cbb11f9d85c8ab3745d5b913a. (Refer to https://sourceforge.net/p/libjpeg-turbo/patches/57). - Modify the SSE2 baseline Huffman encoder so that the C Huffman encoders can share its definition of jpeg_nbits_table. - Move the definition of jpeg_nbits_table into a C source file (jpeg_nbits.c) rather than a header, and define the table only if USE_CLZ_INTRINSIC is undefined and the SSE2 baseline Huffman encoder will not be built. - Apply hidden symbol visibility to the shared definition of jpeg_nbits_table, if the compiler supports the necessary attribute. (In practice, only Visual C++ doesn't.) Closes #114 See also: https://bugzilla.mozilla.org/show_bug.cgi?id=1501523

9c6f79e9

2019-11-13T14:36:37

Fix formatting issues detected by checkstyle

cbf0fcc8

2019-11-05T11:56:06

i386 SSE2 Huffman: Fix pointer arithmetic issue Splitting the pointer arithmetic in GET_SYM() into a separate add and sub instruction was an attempt to work around an error ("invalid operand type") that occurred when assembling the file with NASM. However, this created a link error on macOS ("ld: illegal text-relocation to '_jconst_huff_encode_one_block' in simd/CMakeFiles/simd.dir/i386/jchuff-sse2.asm.o from '_jsimd_huff_encode_one_block_sse2' in simd/CMakeFiles/simd.dir/i386/jchuff-sse2.asm.o for architecture i386") and also changed the alignment of the code in ways that might have affected the previous benchmark results (which took a great deal of time to obtain.) Ultimately, the path of least resistance is just to require NASM 2.13 or later.

087c29e0

2018-10-22T10:05:18

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

3a32d199

2019-10-17T19:59:01

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.

9a51a87a

2019-10-17T11:21:32

x86 SIMD: Remove obsolete [TAB8] comments With apologies to Richard Hendricks, our assembly code no longer uses tabs.

81baa1b5

2018-03-21T13:03:30

simd/i386/jchuff-sse2.asm: Minor formatting tweak

19c791cd

2018-03-08T10:55:20

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.

88421563

2018-02-23T21:56:32

Make SIMD symbols private for x86[-64] ELF builds

c0f3512d

2017-08-31T20:57:19

Merge branch 'master' into dev

6abd3916

2016-11-15T08:47:43

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/

kc3-lang/libjpeg-turbo/simd/i386/jchuff-sse2.asm

simd/i386/jchuff-sse2.asm

Log