Update manpages for new math library.
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# @(#)Makefile 5.1beta 93/09/24
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# $Id: Makefile,v 1.14 1994/02/15 01:00:46 jtc Exp $
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# $Id: Makefile,v 1.15 1994/02/25 19:32:18 jtc Exp $
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#
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# ====================================================
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# Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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@ -84,8 +84,8 @@ MAN3+= acos.0 acosh.0 asin.0 asinh.0 atan.0 atan2.0 atanh.0 ceil.0 \
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MLINKS+=erf.3 erfc.3
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MLINKS+=exp.3 expm1.3 exp.3 log.3 exp.3 log10.3 exp.3 log1p.3 exp.3 pow.3
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MLINKS+=hypot.3 cabs.3
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MLINKS+=ieee.3 copysign.3 ieee.3 drem.3 ieee.3 finite.3 ieee.3 logb.3 \
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ieee.3 scalb.3
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MLINKS+=ieee.3 copysign.3 ieee.3 finite.3 ieee.3 ilogb.3 \
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ieee.3 nextafter.3 ieee.3 remainder.3 ieee.3 scalbn.3
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MLINKS+=j0.3 j1.3 j0.3 jn.3 j0.3 y0.3 j0.3 y1.3 j0.3 yn.3
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MLINKS+=lgamma.3 gamma.3
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MLINKS+=sqrt.3 cbrt.3
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@ -30,47 +30,76 @@
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)ieee.3 6.4 (Berkeley) 5/6/91
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.\" $Id: ieee.3,v 1.5 1993/10/29 17:10:12 jtc Exp $
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.\" $Id: ieee.3,v 1.6 1994/02/25 19:32:26 jtc Exp $
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.\"
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.Dd May 6, 1991
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.Dd Feb 25, 1994
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.Dt IEEE 3
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.Os BSD 4.3
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.Os
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.Sh NAME
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.Nm copysign ,
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.Nm drem ,
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.Nm finite ,
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.Nm logb ,
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.Nm scalb
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.Nd exponent manipulations
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.Nm ilogb ,
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.Nm nextafter ,
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.Nm remainder ,
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.Nm scalbn
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.Nd Functions for IEEE arithmetic
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.Sh SYNOPSIS
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.Fd #include <math.h>
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.Ft double
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.Fn copysign "double x" "double y"
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.Ft double
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.Fn drem "double x" "double y"
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.Ft int
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.Fn finite "double x"
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.Ft int
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.Fn ilogb "double x"
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.Ft double
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.Fn logb "double x"
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.Fn nextafter "double x" "double y"
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.Ft double
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.Fn remainder "double x" "double y"
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.Ft double
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.Fn scalb "double x" "int n"
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.Fn scalbn "double x" "int n"
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.Sh DESCRIPTION
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These functions are required for, or recommended by the
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.Tn IEEE
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standard
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754 for floating\-point arithmetic.
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These functions are required or recommended by
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.St -ieee754 .
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.Pp
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The
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.Fn copysign
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function
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returns
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.Fa x
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with its sign changed to
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.Fa y Ns 's.
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.Pp
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The
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.Fn drem
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function
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.Fn finite
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returns the value 1 just when
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\-\*(If \*(Lt
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.Fa x
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\*(Lt +\*(If;
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otherwise a
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zero is returned
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(when
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.Pf \\*(Ba Ns Fa x Ns \\*(Ba
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= \*(If or
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.Fa x
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is \*(Na
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.Pp
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.Fn ilogb
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returns
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.Fa x Ns 's exponent
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.Fa n ,
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in integer format.
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.Fn ilogb \*(Pm\*(If
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returns
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.Dv INT_MAX u
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and
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.Fn ilogb 0
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returns
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.Dv INT_MIN .
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.Pp
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.Fn nextafter
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returns the next machine representable number from
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.Fa x
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in direction
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.Fa y .
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.Pp
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.Fn remainder
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returns the remainder
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.Fa r
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:=
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@ -103,166 +132,21 @@ the remainder is computed exactly and
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.Pf \\*(Ba Fa y No \\*(Ba/2.
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.Sm on
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But
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.Fn drem x 0
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is exceptional.
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(See below under
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.Sx DIAGNOSTICS . )
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.Fn remainder x 0
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and
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.Fn remainder \*(If 0
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are invalid operations that produce a \*(Na.
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.Pp
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The
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.Fn finite
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function returns the value 1 just when
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\-\*(If \*(Lt
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.Fa x
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\*(Lt +\*(If;
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otherwise a
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zero is returned
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(when
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.Pf \\*(Ba Ns Fa x Ns \\*(Ba
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= \*(If or
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.Fa x
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is \*(Na or
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is the
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.Tn VAX Ns 's
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reserved operand).
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.Pp
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The
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.Fn logb
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function returns
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.Fa x Ns 's exponent
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.Fa n ,
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a signed integer converted to double\-precision floating\-point and so
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chosen that
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1 (<=
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.Pf \\*(Ba Ns Fa x Ns \\*(Ba2** Ns Fa n
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< 2
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unless
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.Fa x
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= 0 or
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(only on machines that conform to
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.Tn IEEE
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754)
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.Pf \\*(Ba Fa x Ns \\*(Ba
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= \*(If
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or
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.Fa x
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lies between 0 and the Underflow Threshold.
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(See below under
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.Sx BUGS . )
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.Pp
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The
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Fn scalb
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.Fn scalbn
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returns
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.Fa x Ns \(**(2** Ns Fa n )
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computed, for integer n, without first computing
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.Pf 2\(** Fa n .
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.Sh RETURN VALUES
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The
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.Tn IEEE
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standard
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754 defines
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.Fn drem x 0
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and
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.Fn drem \\*(If y
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to be invalid operations that produce a \*(Na.
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On the
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.Tn VAX ,
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.Fn drem x 0
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generates a reserved operand fault. No \*(If
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exists on a
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.Tn VAX .
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.Pp
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.Tn IEEE
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754 defines
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.if n \
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.Fn logb \(+-\\*(If
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= \*(If and
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.Fn logb 0
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= \-\*(If, and
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requires the latter to signal Division\-by\-Zero.
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But on a
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.Tn VAX ,
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.Fn logb 0
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= 1.0 \- 2.0**31 = \-2,147,483,647.0.
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And if the correct value of
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.Fn scalb
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would overflow on a
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.Tn VAX ,
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it generates a reserved operand fault and sets the global variable
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.Va errno
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to
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.Dv ERANGE .
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computed by exponent manipulation.
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.Sh SEE ALSO
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.Xr floor 3 ,
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.Xr math 3 ,
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.Xr infnan 3
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.Xr math 3
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.Sh HISTORY
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The
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.Nm ieee
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functions appeared in
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.Bx 4.3 .
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.Sh BUGS
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Should
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.Fn drem x 0
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and
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.Fn logb 0
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on a
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.Tn VAX
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signal invalidity
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by setting
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.Va errno No = Dv EDOM ?
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Should
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.Fn logb 0
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return \-1.7e38?
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.Pp
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.Tn IEEE
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754 currently specifies that
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.Fn logb "denormalized no."
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=
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.Fn logb "tiniest normalized no. > 0"
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but the consensus has changed to the specification in the new
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proposed
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.Tn IEEE
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standard p854, namely that
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.Fn logb x
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satisfy
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.Bd -filled -offset indent
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1 \(<=
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.Fn scalb \\*(Bax\\*(Ba \-logb(x)
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<
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Radix\0 ... = 2
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for
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.Tn IEEE
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754
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.Ed
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.Pp
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for every x except 0,
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\*(If
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and \*(Na.
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Almost every program that assumes 754's specification will work
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correctly if
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.Fn logb
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follows 854's specification instead.
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.Pp
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.Tn IEEE
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754 requires
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.Fn copysign x \\*(Na)
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=
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.Pf \(+- Ns Fa x
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but says nothing
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else about the sign of a \*(Na. A \*(Na
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.Em N Ns ot
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.Em a
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.Em N Ns umber )
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is
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similar in spirit to the
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.Tn VAX Ns 's
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reserved operand, but very
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different in important details. Since the sign bit of a
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reserved operand makes it look negative,
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.Bd -filled -offset indent
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.Fn copysign x "reserved operand"
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=
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.Pf \- Fa x ;
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.Ed
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.Pp
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should this return the reserved operand instead?
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.Sh STANDARDS
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.St -ieee754
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