From 30a25f3742287697bc57a1bef86c19ecf5129322 Mon Sep 17 00:00:00 2001 From: Jia Tan Date: Mon, 22 Jan 2024 22:08:45 +0800 Subject: [PATCH] Docs: Add --disable-arm64-crc32 description to INSTALL. --- INSTALL | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/INSTALL b/INSTALL index d6eaa616..670e3989 100644 --- a/INSTALL +++ b/INSTALL @@ -372,7 +372,7 @@ XZ Utils Installation code. --disable-clmul-crc - Disable the use carryless multiplication for CRC + Disable the use of carryless multiplication for CRC calculation even if compiler support for it is detected. The code uses runtime detection of SSSE3, SSE4.1, and CLMUL instructions on x86. On 32-bit x86 this currently @@ -383,6 +383,16 @@ XZ Utils Installation required extensions (-msse4.1 -mpclmul) then runtime detection isn't used and the generic code is omitted. + --disable-arm64-crc32 + Disable the use of the ARM64 CRC32 instruction extension + even if compiler support for it is detected. The code will + detect support for the instruction at runtime. + + If using compiler options that unconditionally allow the + required extensions (-march=armv8-a+crc or -march=armv8.1-a + and later) then runtime detection isn't used and the + generic code is omitted. + --enable-unaligned-access Allow liblzma to use unaligned memory access for 16-bit, 32-bit, and 64-bit loads and stores. This should be