Add and document ffsl(), fls() and flsl().
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dfa5456537
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@ -42,6 +42,9 @@ int bcmp(const void *, const void *, size_t); /* LEGACY */
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void bcopy(const void *, void *, size_t); /* LEGACY */
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void bzero(void *, size_t); /* LEGACY */
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int ffs(int);
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int ffsl(long);
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int fls(int);
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int flsl(long);
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char *index(const char *, int); /* LEGACY */
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char *rindex(const char *, int); /* LEGACY */
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int strcasecmp(const char *, const char *);
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@ -83,8 +83,8 @@ SRCS+= ${_src}
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KQSRCS= adddi3.c anddi3.c ashldi3.c ashrdi3.c cmpdi2.c divdi3.c iordi3.c \
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lshldi3.c lshrdi3.c moddi3.c muldi3.c negdi2.c notdi2.c qdivrem.c \
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subdi3.c ucmpdi2.c udivdi3.c umoddi3.c xordi3.c
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KSRCS= bcmp.c ffs.c index.c mcount.c rindex.c strcat.c strcmp.c strcpy.c \
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strlen.c strncpy.c
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KSRCS= bcmp.c ffs.c ffsl.c fls.c flsl.c index.c mcount.c rindex.c \
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strcat.c strcmp.c strcpy.c strlen.c strncpy.c
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libkern: libkern.gen libkern.${MACHINE_ARCH}
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@ -6,7 +6,8 @@
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CFLAGS+= -I${.CURDIR}/locale
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# machine-independent string sources
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MISRCS+=bcmp.c bcopy.c bzero.c ffs.c index.c memccpy.c memchr.c memcmp.c \
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MISRCS+=bcmp.c bcopy.c bzero.c ffs.c ffsl.c fls.c flsl.c index.c memccpy.c \
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memchr.c memcmp.c \
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memcpy.c memmove.c memset.c rindex.c stpcpy.c strcasecmp.c strcat.c \
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strchr.c strcmp.c strcoll.c strcpy.c strcspn.c strdup.c strerror.c \
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strlcat.c strlcpy.c strlen.c strmode.c strncat.c strncmp.c strncpy.c \
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@ -32,6 +33,9 @@ MAN+= bcmp.3 bcopy.3 bstring.3 bzero.3 ffs.3 index.3 memccpy.3 memchr.3 \
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strspn.3 strstr.3 strtok.3 strxfrm.3 swab.3 wcscoll.3 wcstok.3 \
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wcswidth.3 wcsxfrm.3 wmemchr.3
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MLINKS+=ffs.3 ffsl.3
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MLINKS+=ffs.3 fls.3
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MLINKS+=ffs.3 flsl.3
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MLINKS+=index.3 rindex.3
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MLINKS+=strcasecmp.3 strncasecmp.3
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MLINKS+=strcat.3 strncat.3
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@ -38,23 +38,44 @@
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.Dt FFS 3
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.Os
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.Sh NAME
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.Nm ffs
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.Nd find first bit set in a bit string
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.Nm ffs ,
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.Nm ffsl ,
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.Nm fls ,
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.Nm flsl
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.Nd find first or last bit set in a bit string
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In strings.h
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.Ft int
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.Fn ffs "int value"
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.Ft int
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.Fn ffsl "long value"
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.Ft int
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.Fn fls "int value"
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.Ft int
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.Fn flsl "long value"
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.Sh DESCRIPTION
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The
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.Fn ffs
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function finds the first bit set in
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and
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.Fn ffsl
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functions find the first bit set in
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.Fa value
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and returns the index of that bit.
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and return the index of that bit.
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.Pp
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The
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.Fn fls
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and
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.Fn flsl
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functions find the last bit set in
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.Fa value
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and return the index of that bit.
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.Pp
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Bits are numbered starting from 1, starting at the right-most
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bit.
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A return value of 0 means that the argument was zero.
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(least significant) bit.
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A return value of zero from any of these functions means that the
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argument was zero.
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.Sh SEE ALSO
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.Xr bitstring 3
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.Sh HISTORY
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@ -69,3 +90,11 @@ before it was moved to
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for
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.St -p1003.1-2001
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compliance.
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.Pp
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The
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.Fn ffsl ,
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.Fn fls
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and
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.Fn flsl
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functions appeared in
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.Fx 5.3 .
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@ -40,7 +40,7 @@ __FBSDID("$FreeBSD$");
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#include <strings.h>
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/*
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* ffs -- vax ffs instruction
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* Find First Set bit
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*/
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int
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ffs(int mask)
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@ -50,6 +50,6 @@ ffs(int mask)
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if (mask == 0)
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return(0);
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for (bit = 1; !(mask & 1); bit++)
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mask >>= 1;
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return(bit);
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(unsigned int)mask >>= 1;
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return (bit);
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}
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52
lib/libc/string/ffsl.c
Normal file
52
lib/libc/string/ffsl.c
Normal file
@ -0,0 +1,52 @@
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <strings.h>
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/*
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* Find First Set bit
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*/
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int
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ffsl(long mask)
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{
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int bit;
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if (mask == 0)
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return(0);
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for (bit = 1; !(mask & 1); bit++)
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(unsigned long)mask >>= 1;
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return (bit);
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}
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52
lib/libc/string/fls.c
Normal file
52
lib/libc/string/fls.c
Normal file
@ -0,0 +1,52 @@
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <strings.h>
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/*
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* Find Last Set bit
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*/
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int
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fls(int mask)
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{
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int bit;
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if (mask == 0)
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return (0);
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for (bit = 1; mask != 1; bit++)
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(unsigned int)mask >>= 1;
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return (bit);
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}
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52
lib/libc/string/flsl.c
Normal file
52
lib/libc/string/flsl.c
Normal file
@ -0,0 +1,52 @@
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <strings.h>
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/*
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* Find Last Set bit
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*/
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int
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flsl(long mask)
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{
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int bit;
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if (mask == 0)
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return (0);
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for (bit = 1; mask != 1; bit++)
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(unsigned long)mask >>= 1;
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return (bit);
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}
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