missing VAX manual for infnan(3), from 4.4 BSD

2 files changed, 184 insertions, 1 deletions

diff --git a/lib/libm/Makefile b/lib/libm/Makefile
index c4662314aa8..db35e854131 100644
--- a/lib/libm/Makefile
+++ b/lib/libm/Makefile
@@ -1,5 +1,5 @@
 #  $NetBSD: Makefile,v 1.28 1995/11/20 22:06:19 jtc Exp $
-#  $OpenBSD: Makefile,v 1.10 1997/03/25 17:07:33 rahnds Exp $
+#  $OpenBSD: Makefile,v 1.11 1997/09/01 02:13:12 mickey Exp $
 #
 #  @(#)Makefile 5.1beta 93/09/24 
 # 
@@ -62,6 +62,7 @@ ARCH_SRCS = e_acos.S e_asin.S e_atanh.S e_cosh.S e_exp.S e_log.S e_log10.S \
 .PATH:	${.CURDIR}/arch/vax
 NOIEEE_ARCH=n_infnan.S n_argred.S n_sqrt.S
 ARCH_SRCS = n_atan2.S n_cabs.S n_cbrt.S n_sincos.S n_tan.S n_support.S 
+MAN+=infnan.3
 .endif
 
 .if (${MACHINE_ARCH} == "mvme88k")
diff --git a/lib/libm/man/infnan.3 b/lib/libm/man/infnan.3
new file mode 100644
index 00000000000..a27eee52c29
--- /dev/null
+++ b/lib/libm/man/infnan.3
@@ -0,0 +1,182 @@
+.\"	$OpenBSD: infnan.3,v 1.1 1997/09/01 02:13:13 mickey Exp $
+.\"
+.\" Copyright (c) 1985, 1991, 1993
+.\"	The Regents of the University of California.  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.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"	This product includes software developed by the University of
+.\"	California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+.\"
+.\"     @(#)infnan.3	8.1 (Berkeley) 6/4/93
+.\"
+.Dd June 4, 1993
+.Dt INFNAN 3 vax
+.Os
+.Sh NAME
+.Nm infnan
+.Nd signals invalid floating\-point operations on a
+.Tn VAX
+(temporary)
+.Sh SYNOPSIS
+.Fd #include <math.h>
+.Ft double 
+.Fn infnan "int iarg"
+.Sh DESCRIPTION
+At some time in the future, some of the useful properties of
+the Infinities and \*(Nas in the
+.Tn IEEE
+standard 754 for Binary
+Floating\-Point Arithmetic will be simulated in
+.Tn UNIX
+on the
+.Tn DEC VAX
+by using its Reserved Operands.  Meanwhile, the
+Invalid, Overflow and Divide\-by\-Zero exceptions of the
+.Tn IEEE
+standard are being approximated on a
+.Tn VAX
+by calls to a
+procedure
+.Fn infnan
+in appropriate places in
+.Xr libm 3 .
+When
+better exception\-handling is implemented in
+.Tn UNIX , 
+only
+.Fn infnan
+among the codes in
+.Xr libm
+will have to be changed.
+And users of
+.Xr libm
+can design their own
+.Fn infnan
+now to
+insulate themselves from future changes.
+.Pp
+Whenever an elementary function code in
+.Xr libm
+has to
+simulate one of the aforementioned
+.Tn IEEE
+exceptions, it calls
+.Fn infnan iarg
+with an appropriate value of
+.Fa iarg .
+Then a
+reserved operand fault stops computation.  But
+.Fn infnan
+could
+be replaced by a function with the same name that returns
+some plausible value, assigns an apt value to the global
+variable
+.Va errno ,
+and allows computation to resume.
+Alternatively, the Reserved Operand Fault Handler could be
+changed to respond by returning that plausible value, etc.
+instead of aborting.
+.Pp
+In the table below, the first two columns show various
+exceptions signaled by the
+.Tn IEEE
+standard, and the default
+result it prescribes.  The third column shows what value is
+given to
+.Fa iarg
+by functions in
+.Xr libm
+when they
+invoke
+.Fn infnan iarg
+under analogous circumstances on a
+.Tn VAX . 
+Currently
+.Fn infnan
+stops computation under all those
+circumstances.  The last two columns offer an alternative;
+they suggest a setting for
+.Va errno
+and a value for a
+revised
+.Fn infnan
+to return.  And a C program to
+implement that suggestion follows. 
+.sp 0.5
+.Bd -filled -offset indent
+.Bl -column "IEEE Signal" "IEEE Default" XXERANGE ERANGEXXorXXEDOM
+.It IEEE Signal	IEEE Default Ta
+.Fa iarg Ta
+.Va errno Ta
+.Fn infnan
+.It Invalid	\*(Na Ta
+.Dv EDOM	EDOM	0
+.It Overflow	\(+-\*(If Ta
+.Dv ERANGE	ERANGE	HUGE
+.It Div\-by\-0	\(+-Infinity Ta
+.Dv \(+-ERANGE	ERANGE or EDOM	\(+-HUGE
+.It 	( Ns Dv HUGE No "= 1.7e38 ... nearly  2.0**127)"
+.El
+.Ed
+.Pp
+ALTERNATIVE
+.Fn infnan :
+.Bd -literal -offset indent
+#include	<math.h>
+#include	<errno.h>
+extern int	errno ;
+double	infnan(iarg)
+int	iarg ;
+{
+	switch(iarg) {
+	case	\0ERANGE:	errno = ERANGE; return(HUGE);
+	case	\-ERANGE:	errno = EDOM;	return(\-HUGE);
+	default:		errno = EDOM;	return(0);
+	}
+}
+.Ed
+.Sh SEE ALSO
+.Xr math 3 ,
+.Xr intro 2 ,
+.Xr signal 3 .
+.Pp
+.Dv ERANGE
+and
+.Dv EDOM
+are defined in
+.Aq Pa errno.h .
+(See
+.Xr intro 2
+for explanation of
+.Dv EDOM
+and
+.Dv ERANGE . )
+.Sh HISTORY
+The
+.Fn infnan
+function appeared in 
+.Bx 4.3 .