xref: /freebsd/lib/msun/man/ieee_test.3 (revision 05c7a37afb48ddd5ee1bd921a5d46fe59cc70b15)
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32.\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
33.\"	$Id: ieee_test.3,v 1.1.1.1 1994/08/19 09:39:43 jkh Exp $
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35.Dd March 10, 1994
36.Dt IEEE_TEST 3
37.Os
38.Sh NAME
39.Nm logb ,
40.Nm logbf ,
41.Nm scalb ,
42.Nm scalbf ,
43.Nm significand ,
44.Nm significandf
45.Nd IEEE test functions
46.Sh SYNOPSIS
47.Fd #include <math.h>
48.Ft double
49.Fn logb "double x"
50.Ft float
51.Fn logbf "float x"
52.Ft double
53.Fn scalb "double x" "double n"
54.Ft float
55.Fn scalbf "float x" "float n"
56.Ft double
57.Fn significand "double x"
58.Ft float
59.Fn significandf "float x"
60.Sh DESCRIPTION
61These functions allow users to test conformance to
62.St -ieee754 .
63Their use is not otherwise recommended.
64.Pp
65.Fn logb x
66and
67.Fn logbf x
68return
69.Fa x Ns 's exponent
70.Fa n ,
71a signed integer converted to double\-precision floating\-point.
72.Fn logb \*(Pm\*(If
73= +\*(If;
74.Fn logb 0
75= -\*(If with a division by zero exception.
76.Pp
77.Fn scalbn x n
78and
79.Fn scalbnf x n
80return
81.Fa x Ns \(**(2** Ns Fa n )
82computed by exponent manipulation.
83.Pp
84.Fn significand x
85and
86.Fn significandf x
87return
88.Fa sig ,
89where
90.Fa x
91:=
92.Fa sig No \(** 2** Ns Fa n
93with 1 \(<=
94.Fa sig
95< 2.
96.Fn significand x
97and
98.Fn significandf x
99are not defined when
100.Fa x
101is 0, \*(Pm\*(If, or \*(Na.
102.Sh SEE ALSO
103.Xr ieee 3 ,
104.Xr math 3
105
106.Sh STANDARDS
107.St -ieee754
108