Split out the ilogb(3) family out of ieee(3) and properly document it.

This commit is contained in:
jruoho 2011-05-10 06:38:33 +00:00
parent de9a772ed6
commit 31061e207a
3 changed files with 114 additions and 24 deletions

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@ -1,4 +1,4 @@
# $NetBSD: Makefile,v 1.107 2011/04/16 05:48:50 jruoho Exp $
# $NetBSD: Makefile,v 1.108 2011/05/10 06:38:33 jruoho Exp $
#
# @(#)Makefile 5.1beta 93/09/24
#
@ -204,7 +204,7 @@ MAN+= acos.3 acosh.3 asin.3 asinh.3 atan.3 atan2.3 atanh.3 \
ceil.3 copysign.3 cos.3 cosh.3 \
erf.3 exp.3 \
fabs.3 fmod.3 frexp.3 hypot.3 ieee.3 \
ieee_test.3 isinff.3 j0.3 ldexp.3 lgamma.3 lrint.3 \
ieee_test.3 ilogb.3 isinff.3 j0.3 ldexp.3 lgamma.3 lrint.3 \
math.3 modf.3 nextafter.3 \
remainder.3 rint.3 round.3 \
sin.3 sinh.3 sqrt.3 \
@ -249,11 +249,11 @@ MLINKS+=fabs.3 fabsf.3
MLINKS+=fmod.3 fmodf.3
MLINKS+=hypot.3 hypotf.3
MLINKS+=ieee.3 finite.3 ieee.3 finitef.3 \
ieee.3 ilogb.3 ieee.3 ilogbf.3 \
ieee.3 scalbn.3 ieee.3 scalbnf.3
MLINKS+=ieee_test.3 logb.3 ieee_test.3 logbf.3
MLINKS+=ieee_test.3 scalb.3 ieee_test.3 scalbf.3
MLINKS+=ieee_test.3 significand.3 ieee_test.3 significandf.3
MLINKS+=ilogb.3 ilogbf.3 \
MLINKS+=isinff.3 isnanf.3
MLINKS+=j0.3 j0f.3 j0.3 j1.3 j0.3 j1f.3 j0.3 jn.3 j0.3 jnf.3 \
j0.3 y0.3 j0.3 y0f.3 j0.3 y1.3 j0.3 y1f.3 j0.3 yn.3 j0.3 ynf.3

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@ -26,7 +26,7 @@
.\" SUCH DAMAGE.
.\"
.\" from: @(#)ieee.3 6.4 (Berkeley) 5/6/91
.\" $NetBSD: ieee.3,v 1.24 2011/04/13 04:57:10 jruoho Exp $
.\" $NetBSD: ieee.3,v 1.25 2011/05/10 06:38:33 jruoho Exp $
.\"
.Dd April 12, 2011
.Dt IEEE 3
@ -34,8 +34,6 @@
.Sh NAME
.Nm finite ,
.Nm finitef ,
.Nm ilogb ,
.Nm ilogbf ,
.Nm scalbn ,
.Nm scalbnf
.Nd functions for IEEE arithmetic
@ -47,10 +45,6 @@
.Fn finite "double x"
.Ft int
.Fn finitef "float x"
.Ft int
.Fn ilogb "double x"
.Ft int
.Fn ilogbf "float x"
.Ft double
.Fn scalbn "double x" "int n"
.Ft float
@ -72,20 +66,6 @@ zero is returned
.Fa x
is \*(Na).
.Pp
.Fn ilogb
returns
.Fa x Ns 's exponent
.Fa n ,
in integer format.
.Fn ilogb \*(Pm\*(If
returns
.Dv INT_MAX
and
.Fn ilogb 0
returns
.Dv INT_MIN .
is even.
.Pp
.Fn scalbn
returns
.Fa x Ns \(**(2** Ns Fa n )

110
lib/libm/man/ilogb.3 Normal file
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@ -0,0 +1,110 @@
.\" $NetBSD: ilogb.3,v 1.1 2011/05/10 06:38:33 jruoho Exp $
.\"
.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi>
.\" 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
.\"
.Dd May 10, 2011
.Dt ILOGB 3
.Os
.Sh NAME
.Nm ilogb ,
.Nm ilogbf
.Nd an unbiased exponent
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft int
.Fn ilogb "double x"
.Ft int
.Fn ilogbf "float x"
.Sh DESCRIPTION
The
.Fn ilogb
and
.Fn ilogbf
functions return the exponent of the non-zero real floating-point number
.Fa x
as a signed integer value.
Formally the return value is the integral part of
.Bd -ragged -offset indent
log_r |
.Va x | ,
.Ed
.Pp
where
.Fa r
is the radix of the machine's floating-point arithmetic defined by the
.Dv FLT_RADIX
constant in
.In float.h .
.Sh RETURN VALUES
As described above, upon successful completion,
the functions return the exponent.
Functionally this is the same as calling the corresponding
.Xr logb 3
function and casting the return value to
.Vt int .
.Pp
The following special cases may occur:
.Bl -enum -offset indent
.It
If
.Fa x
is zero, the value of
.Dv FP_ILOGB0
is returned and a domain error occurs.
.It
If
.Fa x
is infinite, a domain error occurs and the value of
.Dv INT_MAX
is returned.
.It
If
.Fa x
is \*(Na, a domain error is raised and the value of
.Dv FP_ILOGBNAN
is returned.
.It
If the correct value is outside the range of the return type,
a domain error occurs but an unspecified value is returned.
.El
.Sh SEE ALSO
.Xr ilog2 3 ,
.Xr logb 3 ,
.Xr math 3
.Sh STANDARDS
The described functions conform to
.St -isoC-99 .
.Sh BUGS
Neither
.Dv FP_ILOGB0
nor
.Dv FP_ILOGBNAN
is defined currently in
.Nx .
Furthermore, the
.Vt long double
variant of the functions is not yet supported.