Implement C99's signbit() macro.

svn path=/head/; revision=110734

lib/libc/gen/Makefile.inc

@@ -24,7 +24,7 @@ SRCS+=  __xuname.c _pthread_stubs.c _rand48.c _spinlock_stub.c _thread_init.c \
 	scandir.c seed48.c seekdir.c semctl.c \
 	setdomainname.c sethostname.c setjmperr.c setmode.c \
 	setproctitle.c setprogname.c \
-	siginterrupt.c siglist.c signal.c \
+	siginterrupt.c siglist.c signal.c signbit.c \
 	sigsetops.c sleep.c srand48.c statvfs.c stringlist.c strtofflags.c \
 	sysconf.c sysctl.c sysctlbyname.c sysctlnametomib.c \
 	syslog.c telldir.c termios.c time.c times.c timezone.c ttyname.c \
@@ -53,7 +53,8 @@ MAN+=	alarm.3 arc4random.3 \
 	nice.3 nlist.3 pause.3 popen.3 pselect.3 psignal.3 pwcache.3 \
 	raise.3 rand48.3 readpassphrase.3 rfork_thread.3 \
 	scandir.3 setjmp.3 setmode.3 setproctitle.3 shm_open.3 \
-	siginterrupt.3 signal.3 sigsetops.3 sleep.3 statvfs.3 stringlist.3 \
+	siginterrupt.3 signal.3 signbit.3 sigsetops.3 sleep.3 \
+	statvfs.3 stringlist.3 \
 	strtofflags.3 sysconf.3 sysctl.3 syslog.3 tcgetpgrp.3 \
 	tcsendbreak.3 tcsetattr.3 tcsetpgrp.3 time.3 times.3 timezone.3 \
 	ttyname.3 tzset.3 ualarm.3 ucontext.3 ulimit.3 uname.3 \

lib/libc/gen/signbit.3

@@ -0,0 +1,57 @@
+.\" Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd February 11, 2003
+.Dt FPCLASSIFY 3
+.Os
+.Sh NAME
+.Nm signbit
+.Nd "determine whether a floating-point number's sign is negative"
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In math.h
+.Ft int
+.Fn signbit "real-floating x"
+.Sh DESCRIPTION
+The
+.Fn signbit
+macro takes an argument of
+.Va x
+and returns non-zero if the value of its sign is negative, otherwise 0.
+.Sh SEE ALSO
+.Xr fpclassify 3 ,
+.Xr math 3
+.Sh STANDARDS
+The
+.Fn signbit
+macro conforms to
+.St -isoC-99 .
+.Sh HISTORY
+The
+.Fn signbit
+macro was added in
+.Fx 5.1 .

lib/libc/gen/signbit.c

@@ -0,0 +1,40 @@
+/*-
+ * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <math.h>
+
+#include "fpmath.h"
+
+int
+__signbit(double d)
+{
+	union IEEEd2bits u;
+
+	u.d = d;
+	return (u.bits.sign);
+}

lib/msun/src/math.h

@@ -50,6 +50,7 @@ extern const union __nan_un {
     ((sizeof (x) == sizeof (float)) ? __fpclassifyf(x) \
     : (sizeof (x) == sizeof (double)) ? __fpclassifyd(x) \
     : __fpclassifyl(x))
+#define	signbit(x)	__signbit(x)
 
 typedef	__double_t	double_t;
 typedef	__float_t	float_t;
@@ -147,6 +148,7 @@ __BEGIN_DECLS
 int	__fpclassifyd(double);
 int	__fpclassifyf(float);
 int	__fpclassifyl(long double);
+int	__signbit(double);
 
 double	acos(double);
 double	asin(double);