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git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/ieee754/ldbl-128/s_logbl.c
1 /* s_logbl.c -- long double version of s_logb.c.
2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
13 * ====================================================
16 #if defined(LIBM_SCCS) && !defined(lint)
17 static char rcsid
[] = "$NetBSD: $";
21 * long double logbl(x)
22 * IEEE 754 logb. Included to pass IEEE test suite. Not recommend.
27 #include <math_private.h>
30 __logbl (long double x
)
34 GET_LDOUBLE_WORDS64 (hx
, lx
, x
);
35 hx
&= 0x7fffffffffffffffLL
; /* high |x| */
37 return -1.0 / fabsl (x
);
38 if (hx
>= 0x7fff000000000000LL
)
40 if ((ex
= hx
>> 48) == 0) /* IEEE 754 logb */
42 /* POSIX specifies that denormal number is treated as
43 though it were normalized. */
46 ma
= __builtin_clzll (lx
) + 64;
48 ma
= __builtin_clzll (hx
);
51 return (long double) (ex
- 16383);
54 weak_alias (__logbl
, logbl
)