[PATCH 4/4] x86: Expand the comment on when REP STOSB is used on memset

Adhemerval Zanella adhemerval.zanella@linaro.org
Tue Oct 31 20:09:25 GMT 2023


---
 sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
index 3d9ad49cb9..0821b32997 100644
--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
@@ -21,7 +21,9 @@
    2. If size is less than VEC, use integer register stores.
    3. If size is from VEC_SIZE to 2 * VEC_SIZE, use 2 VEC stores.
    4. If size is from 2 * VEC_SIZE to 4 * VEC_SIZE, use 4 VEC stores.
-   5. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
+   5. On machines ERMS feature, if size is greater or equal than
+      __x86_rep_stosb_threshold then REP STOSB will be used.
+   6. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
       4 VEC stores and store 4 * VEC at a time until done.  */
 
 #include <sysdep.h>
-- 
2.34.1



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