simd/arm/jcsample-neon.c


Log

Author Commit Date CI Message
DRC 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.)
DRC 98c45838 2025-08-21T11:22:51 Fix issues with Windows Arm64EC builds Arm64EC basically wraps native Arm64 functions with an emulated Windows/x64 ABI, which can improve performance for Windows/x64 applications running under the x64 emulator on Windows/Arm. When building for Arm64EC, the compiler defines _M_X64 and _M_ARM64EC but not _M_ARM64.
DRC ea4ee229 2024-12-11T16:51:39 Neon: Disable some strict compiler warnings We use a standard set of strict compiler warnings with Clang and GCC to continuously test and maintain C89 conformance in the libjpeg API code. However, SIMD extensions need not comply with that. The Neon code specifically uses some C99isms, so disable -Wdeclaration-after-statement, -Wc99-extensions, and -Wpedantic in the scope of that code. Also modify the Neon feature tests so that they will succeed if any of the aforementioned compiler warnings are enabled.
DRC e69dd40c 2024-01-23T13:26:41 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
Jonathan Wright eb14189c 2020-11-17T12:48:49 Fix Neon SIMD build issues with Visual Studio - Use the _M_ARM and _M_ARM64 macros provided by Visual Studio for compile-time detection of Arm builds, since __arm__ and __aarch64__ are only present in GNU-compatible compilers. - Neon/intrinsics: Use the _CountLeadingZeros() and _CountLeadingZeros64() intrinsics provided by Visual Studio, since __builtin_clz() and __builtin_clzl() are only present in GNU-compatible compilers. - Neon/intrinsics: Since Visual Studio does not support static vector initialization, replace static initialization of Neon vectors with the appropriate intrinsics. Compared to the static initialization approach, this produces identical assembly code with both GCC and Clang. - Neon/intrinsics: Since Visual Studio does not support inline assembly code, provide alternative code paths for Visual Studio whenever inline assembly is used. - Build: Set FLOATTEST appropriately for AArch64 Visual Studio builds (Visual Studio does not emit fused multiply-add [FMA] instructions by default for such builds.) - Neon/intrinsics: Move temporary buffer allocation outside of nested loops. Since Visual Studio configures Arm builds with a relatively small amount of stack memory, attempting to allocate those buffers within the inner loops caused a stack overflow. Closes #461 Closes #475
Jonathan Wright 366168aa 2018-08-06T15:14:34 Neon: Intrinsics impl. of h2v1 & h2v2 downsampling The previous AArch64 GAS implementation has been removed, since the intrinsics implementation provides the same or better performance. There was no previous AArch32 GAS implementation.