git: aae89f6f0957 - main - amd64: use compiler intrinsics for bsf* and bsr*

Mateusz Guzik mjg at FreeBSD.org
Mon Feb 1 05:02:45 UTC 2021


The branch main has been updated by mjg:

URL: https://cgit.FreeBSD.org/src/commit/?id=aae89f6f09576351cc3a9a54959649e60fdd849b

commit aae89f6f09576351cc3a9a54959649e60fdd849b
Author:     Mateusz Guzik <mjg at FreeBSD.org>
AuthorDate: 2021-01-31 23:35:30 +0000
Commit:     Mateusz Guzik <mjg at FreeBSD.org>
CommitDate: 2021-02-01 04:53:23 +0000

    amd64: use compiler intrinsics for bsf* and bsr*
---
 sys/amd64/include/cpufunc.h | 36 ++++--------------------------------
 1 file changed, 4 insertions(+), 32 deletions(-)

diff --git a/sys/amd64/include/cpufunc.h b/sys/amd64/include/cpufunc.h
index 763ed2c64c8a..8ef298e1d7d5 100644
--- a/sys/amd64/include/cpufunc.h
+++ b/sys/amd64/include/cpufunc.h
@@ -65,41 +65,13 @@ breakpoint(void)
 	__asm __volatile("int $3");
 }
 
-static __inline __pure2 u_int
-bsfl(u_int mask)
-{
-	u_int	result;
-
-	__asm __volatile("bsfl %1,%0" : "=r" (result) : "rm" (mask));
-	return (result);
-}
-
-static __inline __pure2 u_long
-bsfq(u_long mask)
-{
-	u_long	result;
-
-	__asm __volatile("bsfq %1,%0" : "=r" (result) : "rm" (mask));
-	return (result);
-}
-
-static __inline __pure2 u_int
-bsrl(u_int mask)
-{
-	u_int	result;
+#define	bsfl(mask)	__builtin_ctz(mask)
 
-	__asm __volatile("bsrl %1,%0" : "=r" (result) : "rm" (mask));
-	return (result);
-}
+#define	bsfq(mask)	__builtin_ctzl(mask)
 
-static __inline __pure2 u_long
-bsrq(u_long mask)
-{
-	u_long	result;
+#define	bsrl(mask)	(__builtin_clz(mask) ^ 0x1f)
 
-	__asm __volatile("bsrq %1,%0" : "=r" (result) : "rm" (mask));
-	return (result);
-}
+#define	bsrq(mask)	(__builtin_clzl(mask) ^ 0x3f)
 
 static __inline void
 clflush(u_long addr)


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