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25 lines
1.2 KiB
25 lines
1.2 KiB
commit 5d070d12b3a52bc44dd1b71743abc4b6243862ae
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Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Date: Thu Feb 8 10:08:40 2024 -0300
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x86: Expand the comment on when REP STOSB is used on memset
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Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
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(cherry picked from commit 491e55beab7457ed310a4a47496f4a333c5d1032)
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diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
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index 9984c3ca0fafab6a..97839a22483b0613 100644
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--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
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+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
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@@ -21,7 +21,9 @@
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2. If size is less than VEC, use integer register stores.
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3. If size is from VEC_SIZE to 2 * VEC_SIZE, use 2 VEC stores.
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4. If size is from 2 * VEC_SIZE to 4 * VEC_SIZE, use 4 VEC stores.
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- 5. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
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+ 5. On machines ERMS feature, if size is greater or equal than
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+ __x86_rep_stosb_threshold then REP STOSB will be used.
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+ 6. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
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4 VEC stores and store 4 * VEC at a time until done. */
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#include <sysdep.h>
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