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30 lines
1.3 KiB
30 lines
1.3 KiB
2 days ago
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From 491e55beab7457ed310a4a47496f4a333c5d1032 Mon Sep 17 00:00:00 2001
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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Date: Thu, 8 Feb 2024 10:08:40 -0300
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Subject: [PATCH] x86: Expand the comment on when REP STOSB is used on memset
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Content-type: text/plain; charset=UTF-8
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Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
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---
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sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S | 4 +++-
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1 file changed, 3 insertions(+), 1 deletion(-)
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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 9984c3ca0f..97839a2248 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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--
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2.39.3
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