Update.
[glibc.git] / sysdeps / libm-ieee754 / s_logbf.c
blobade892a8f9d91201c919ce282acb033d022bfee0
1 /* s_logbf.c -- float version of s_logb.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
5 /*
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
12 * is preserved.
13 * ====================================================
16 #if defined(LIBM_SCCS) && !defined(lint)
17 static char rcsid[] = "$NetBSD: s_logbf.c,v 1.4 1995/05/10 20:47:51 jtc Exp $";
18 #endif
20 #include "math.h"
21 #include "math_private.h"
23 #ifdef __STDC__
24 float __logbf(float x)
25 #else
26 float __logbf(x)
27 float x;
28 #endif
30 int32_t ix;
31 GET_FLOAT_WORD(ix,x);
32 ix &= 0x7fffffff; /* high |x| */
33 if(ix==0) return (float)-1.0/fabsf(x);
34 if(ix>=0x7f800000) return x*x;
35 if((ix>>=23)==0) /* IEEE 754 logb */
36 return -126.0;
37 else
38 return (float) (ix-127);
40 weak_alias (__logbf, logbf)