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From: "Junxian Zhu" <>
To: <>
Cc: "Junxian Zhu" <>
Subject: [PATCH v2] mips: Use builtins for ffs and ffsll
Date: Tue,  6 Feb 2024 16:34:56 +0800	[thread overview]
Message-ID: <> (raw)

From: Junxian Zhu <>

__builtin_ffs{,ll} basically on __builtin_ctz{,ll} in MIPS GCC compiler.
The hardware ctz instructions were available after MIPS{32,64} Release1. By using builtin ctz. It can also reduce code size of ffs/ffsll.

Checked on mips o32. mips64.

Signed-off-by: Junxian Zhu <>
 sysdeps/mips/math-use-builtins-ffs.h | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 sysdeps/mips/math-use-builtins-ffs.h

diff --git a/sysdeps/mips/math-use-builtins-ffs.h b/sysdeps/mips/math-use-builtins-ffs.h
new file mode 100644
index 0000000000..2ab6a03a16
--- /dev/null
+++ b/sysdeps/mips/math-use-builtins-ffs.h
@@ -0,0 +1,3 @@
+#include <sysdep.h>
+#define USE_FFS_BUILTIN (__mips_isa_rev >= 1)
+#define USE_FFSLL_BUILTIN (__mips_isa_rev >= 1)

             reply	other threads:[~2024-02-06  8:35 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-06  8:34 Junxian Zhu [this message]
2024-02-13  7:45 ` Maxim Kuvyrkov

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