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authorLasse Collin <lasse.collin@tukaani.org>2024-01-11 14:39:46 +0200
committerLasse Collin <lasse.collin@tukaani.org>2024-01-11 14:39:46 +0200
commit35c03ec6bf66f1b159964c9721a2dce0e2859b20 (patch)
treeff6f31b68a54170ea2af5166d0e4fe5dbadfecf4 /src/liblzma
parentliblzma: Rename arch-specific CRC functions and macros. (diff)
downloadxz-35c03ec6bf66f1b159964c9721a2dce0e2859b20.tar.xz
liblzma: CRC: Update CLMUL comments to more generic wording.
Diffstat (limited to '')
-rw-r--r--src/liblzma/check/crc32_fast.c16
-rw-r--r--src/liblzma/check/crc64_fast.c10
2 files changed, 13 insertions, 13 deletions
diff --git a/src/liblzma/check/crc32_fast.c b/src/liblzma/check/crc32_fast.c
index 7157e2f4..cf7d75da 100644
--- a/src/liblzma/check/crc32_fast.c
+++ b/src/liblzma/check/crc32_fast.c
@@ -93,10 +93,10 @@ crc32_generic(const uint8_t *buf, size_t size, uint32_t crc)
// Function dispatching //
//////////////////////////
-// If both the generic and CLMUL implementations are built, then the
-// function to use is selected at runtime since system running the
-// binary may not have the CLMUL instructions.
-// The three dispatch methods in order of priority:
+// If both the generic and arch-optimized implementations are built, then
+// the function to use is selected at runtime because the system running
+// the binary might not have the arch-specific instruction set extension(s)
+// available. The three dispatch methods in order of priority:
//
// 1. Indirect function (ifunc). This method is slightly more efficient
// than the constructor method because it will change the entry in the
@@ -195,10 +195,10 @@ extern LZMA_API(uint32_t)
lzma_crc32(const uint8_t *buf, size_t size, uint32_t crc)
{
#if defined(CRC_GENERIC) && defined(CRC_ARCH_OPTIMIZED)
- // If CLMUL is available, it is the best for non-tiny inputs,
- // being over twice as fast as the generic slice-by-four version.
- // However, for size <= 16 it's different. In the extreme case
- // of size == 1 the generic version can be five times faster.
+ // On x86-64, if CLMUL is available, it is the best for non-tiny
+ // inputs, being over twice as fast as the generic slice-by-four
+ // version. However, for size <= 16 it's different. In the extreme
+ // case of size == 1 the generic version can be five times faster.
// At size >= 8 the CLMUL starts to become reasonable. It
// varies depending on the alignment of buf too.
//
diff --git a/src/liblzma/check/crc64_fast.c b/src/liblzma/check/crc64_fast.c
index 4edca1a2..eb1a4ae4 100644
--- a/src/liblzma/check/crc64_fast.c
+++ b/src/liblzma/check/crc64_fast.c
@@ -88,8 +88,8 @@ crc64_generic(const uint8_t *buf, size_t size, uint64_t crc)
// Function dispatching //
//////////////////////////
-// If both the generic and CLMUL implementations are usable, then the
-// function that is used is selected at runtime. See crc32_fast.c.
+// If both the generic and arch-optimized implementations are usable, then
+// the function that is used is selected at runtime. See crc32_fast.c.
typedef uint64_t (*crc64_func_type)(
const uint8_t *buf, size_t size, uint64_t crc);
@@ -160,9 +160,9 @@ lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc)
return crc64_func(buf, size, crc);
#elif defined(CRC_ARCH_OPTIMIZED)
- // If CLMUL is used unconditionally without runtime CPU detection
- // then omitting the generic version and its 8 KiB lookup table
- // makes the library smaller.
+ // If arch-optimized version is used unconditionally without runtime
+ // CPU detection then omitting the generic version and its 8 KiB
+ // lookup table makes the library smaller.
//
// FIXME: Lookup table isn't currently omitted on 32-bit x86,
// see crc64_table.c.