public inbox for libc-alpha@sourceware.org
 help / color / mirror / Atom feed
From: Javier Pello <devel@otheo.eu>
To: libc-alpha@sourceware.org
Subject: [PATCH 2/4] elf: Simplify hwcaps masked value bit counting
Date: Mon, 5 Sep 2022 20:10:27 +0200	[thread overview]
Message-ID: <20220905201027.0338ebf933cfd767cfa83da3@otheo.eu> (raw)
In-Reply-To: <20220905200652.d69204581d15c64647da5cd2@otheo.eu>

Use a simpler way to count the number of bits set in the masked
value in _dl_important_hwcaps.

Signed-off-by: Javier Pello <devel@otheo.eu>
---
 elf/dl-hwcaps.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/elf/dl-hwcaps.c b/elf/dl-hwcaps.c
index 92eb5379..8f11a18f 100644
--- a/elf/dl-hwcaps.c
+++ b/elf/dl-hwcaps.c
@@ -197,8 +197,8 @@ _dl_important_hwcaps (const char *glibc_hwcaps_prepend,
 		  + hwcaps_counts.total_length);
 
   /* Count the number of bits set in the masked value.  */
-  for (n = 0; (~((1ULL << n) - 1) & masked) != 0; ++n)
-    if ((masked & (1ULL << n)) != 0)
+  for (uint64_t mm = masked; mm != 0; mm >>= 1)
+    if ((mm & 1ULL) != 0)
       ++cnt;
 
   /* For TLS enabled builds always add 'tls'.  */
-- 
2.36.0

  parent reply	other threads:[~2022-09-05 18:11 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-05 18:06 [PATCH 0/4] elf: Fix hwcaps string size overestimation Javier Pello
2022-09-05 18:09 ` [PATCH 1/4] " Javier Pello
2022-09-08 10:15   ` Florian Weimer
2022-09-05 18:10 ` Javier Pello [this message]
2022-09-05 18:12 ` [PATCH 3/4] elf: Remove unneeded conditional in _dl_important_hwcaps Javier Pello
2022-09-05 18:13 ` [PATCH 4/4] elf: Simplify hwcaps power set string construction Javier Pello
2022-09-06  7:35 ` [PATCH 0/4] elf: Fix hwcaps string size overestimation Florian Weimer
2022-09-06 18:12   ` Javier Pello
2022-09-08 11:23     ` Florian Weimer
2022-09-14 18:07       ` [PATCH 0/6] Remove legacy hwcaps support Javier Pello
2022-09-14 18:08         ` [PATCH 1/6] elf: Remove legacy hwcaps support from the dynamic loader Javier Pello
2022-09-14 18:10         ` [PATCH 2/6] elf: Remove legacy hwcaps support from ldconfig Javier Pello
2022-09-14 18:10         ` [PATCH 3/6] elf: Remove hwcap parameter from add_to_cache signature Javier Pello
2022-09-14 18:12         ` [PATCH 4/6] elf: Remove hwcap and bits_hwcap fields from struct cache_entry Javier Pello
2022-09-14 18:13         ` [PATCH 5/6] elf: Remove _dl_string_hwcap Javier Pello
2022-09-14 18:15         ` [PATCH 6/6] elf: Simplify output of hwcap subdirectories in ld.so help Javier Pello
2022-09-15  8:42           ` Carlos O'Donell
2022-09-15 19:12             ` Javier Pello
2022-09-14 21:23         ` [PATCH 0/6] Remove legacy hwcaps support Joseph Myers
2022-09-17 14:17         ` [PATCH v2 " Javier Pello
2022-09-17 14:18           ` [PATCH v2 1/6] elf: Remove legacy hwcaps support from the dynamic loader Javier Pello
2022-09-22 11:46             ` Florian Weimer
2022-09-17 14:19           ` [PATCH v2 2/6] elf: Remove legacy hwcaps support from ldconfig Javier Pello
2022-09-22 12:14             ` Florian Weimer
2022-09-17 14:20           ` [PATCH v2 3/6] elf: Remove hwcap parameter from add_to_cache signature Javier Pello
2022-09-22 16:02             ` Florian Weimer
2022-09-17 14:22           ` [PATCH v2 4/6] elf: Remove hwcap and bits_hwcap fields from struct cache_entry Javier Pello
2022-09-22 16:03             ` Florian Weimer
2022-09-17 14:23           ` [PATCH v2 5/6] elf: Remove _dl_string_hwcap Javier Pello
2022-09-17 14:24           ` [PATCH v2 6/6] elf: Simplify output of hwcap subdirectories in ld.so help Javier Pello
2022-09-21 16:26           ` [PATCH v2 0/6] Remove legacy hwcaps support Joseph Myers
2022-09-27 18:03           ` [PATCH v3 0/8] " Javier Pello
2022-09-27 18:05             ` [PATCH v3 1/8] x86_64: Remove platform directory library loading test Javier Pello
2022-10-03 14:56               ` Adhemerval Zanella Netto
2022-10-04 17:53                 ` Javier Pello
2022-10-04 17:59                   ` Adhemerval Zanella Netto
2022-09-27 18:05             ` [PATCH v3 2/8] elf: Remove legacy hwcaps support from the dynamic loader Javier Pello
2022-09-27 18:06             ` [PATCH v3 3/8] elf: Remove legacy hwcaps support from ldconfig Javier Pello
2022-10-03 15:31               ` Adhemerval Zanella Netto
2022-09-27 18:07             ` [PATCH v3 4/8] elf: Remove hwcap parameter from add_to_cache signature Javier Pello
2022-09-27 18:08             ` [PATCH v3 5/8] elf: Remove hwcap and bits_hwcap fields from struct cache_entry Javier Pello
2022-09-27 18:08             ` [PATCH v3 6/8] Add NEWS entry for legacy hwcaps removal Javier Pello
2022-10-03 15:44               ` Adhemerval Zanella Netto
2022-10-03 19:29                 ` Andreas Schwab
2022-10-03 19:49                   ` Adhemerval Zanella Netto
2022-10-03 19:59                     ` Florian Weimer
2022-10-04 18:00                       ` Adhemerval Zanella Netto
2022-10-05 18:12                         ` Javier Pello
2022-10-06 11:03                           ` Adhemerval Zanella Netto
2022-09-27 18:09             ` [PATCH v3 7/8] elf: Remove _dl_string_hwcap Javier Pello
2022-10-03 16:52               ` Adhemerval Zanella Netto
2022-09-27 18:10             ` [PATCH v3 8/8] elf: Simplify output of hwcap subdirectories in ld.so help Javier Pello
2022-10-03 17:02               ` Adhemerval Zanella Netto

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220905201027.0338ebf933cfd767cfa83da3@otheo.eu \
    --to=devel@otheo.eu \
    --cc=libc-alpha@sourceware.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).