minix/lib/nbsd_libm/src/s_logbf.c
Gianluca Guida 0dc9e0996a Import unmodified NetBSD's libm for compiling with new libc.
As the current libc includes a libm implementation, with the new libc
this is needed. Unneeded (for the moment) archs have been removed.
2011-03-18 15:52:16 +00:00

36 lines
949 B
C

/* s_logbf.c -- float version of s_logb.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include <sys/cdefs.h>
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: s_logbf.c,v 1.7 2002/05/26 22:01:57 wiz Exp $");
#endif
#include "math.h"
#include "math_private.h"
float
logbf(float x)
{
int32_t ix;
GET_FLOAT_WORD(ix,x);
ix &= 0x7fffffff; /* high |x| */
if(ix==0) return (float)-1.0/fabsf(x);
if(ix>=0x7f800000) return x*x;
if((ix>>=23)==0) /* IEEE 754 logb */
return -126.0;
else
return (float) (ix-127);
}