diff options
| author | Jack O'Connor <[email protected]> | 2020-10-20 11:59:25 -0400 |
|---|---|---|
| committer | Jack O'Connor <[email protected]> | 2020-10-20 12:05:27 -0400 |
| commit | b9287018935476a26389f22a14a0d2ec763e956c (patch) | |
| tree | 30971480f6274ca3a3096cd0742bde2d4765f8f5 | |
| parent | 5361572c4a0d89e5ac9cf14c0f7358a6b7c80ed2 (diff) | |
readme tweaks
| -rw-r--r-- | c/README.md | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/c/README.md b/c/README.md index f7d8cc8..6211243 100644 --- a/c/README.md +++ b/c/README.md @@ -181,12 +181,12 @@ expects to be linked with code for five different instruction sets: portable C, SSE2, SSE4.1, AVX2, and AVX-512. For each of the x86 SIMD instruction sets, two versions are available, -one in assembly (with three flavors: Unix, Windows MSVC, and Windows -GNU) and one using C intrinsics. The assembly versions are generally -preferred: they perform better, they perform more consistently across -different compilers, and they build more quickly. On the other hand, the -assembly versions are x86\_64-only, and you need to select the right -flavor for your target platform. +one in assembly (which is further divided into three flavors: Unix, +Windows MSVC, and Windows GNU) and one using C intrinsics. The assembly +versions are generally preferred: they perform better, they perform more +consistently across different compilers, and they build more quickly. On +the other hand, the assembly versions are x86\_64-only, and you need to +select the right flavor for your target platform. Here's an example of building a shared library on x86\_64 Linux using the assembly implementations: @@ -212,12 +212,12 @@ gcc -shared -O3 -o libblake3.so blake3.c blake3_dispatch.c blake3_portable.c \ ``` Note above that building `blake3_avx512.c` requires both `-mavx512f` and -`-mavx512vl` under GCC and Clang, as shown above. Under MSVC, the single -`/arch:AVX512` flag is sufficient. The MSVC equivalent of `-mavx2` is -`/arch:AVX2`. MSVC enables SSE4.1 by defaut, and it doesn't have a +`-mavx512vl` under GCC and Clang. Under MSVC, the single `/arch:AVX512` +flag is sufficient. The MSVC equivalent of `-mavx2` is `/arch:AVX2`. +MSVC enables SSE2 and SSE4.1 by defaut, and it doesn't have a corresponding flag. -If you want to omit SIMD code on x86, you need to explicitly disable +If you want to omit SIMD code entirely, you need to explicitly disable each instruction set. Here's an example of building a shared library on x86 with only portable code: |