OpenLibm/src/s_ilogb.c
Ed Schouten 7e5585aaca Rename openlibm.h to openlibm_math.h.
This is a bit more consistent with the naming of the other header files
(openlibm_complex.h and openlibm_fenv.h). Re-add an openlibm.h header
that includes all of the public headers as a shorthand.

Fix up all of the source files to include <openlibm_math.h> instead of
<openlibm.h>. While there, fix ordering of the includes.
2015-01-11 23:37:01 +01:00

49 lines
1.2 KiB
C

/* @(#)s_ilogb.c 5.1 93/09/24 */
/*
* ====================================================
* 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 "cdefs-compat.h"
//__FBSDID("$FreeBSD: src/lib/msun/src/s_ilogb.c,v 1.10 2008/02/22 02:30:35 das Exp $");
/* ilogb(double x)
* return the binary exponent of non-zero x
* ilogb(0) = FP_ILOGB0
* ilogb(NaN) = FP_ILOGBNAN (no signal is raised)
* ilogb(inf) = INT_MAX (no signal is raised)
*/
#include <limits.h>
#include <openlibm_math.h>
#include "math_private.h"
DLLEXPORT int
ilogb(double x)
{
int32_t hx,lx,ix;
EXTRACT_WORDS(hx,lx,x);
hx &= 0x7fffffff;
if(hx<0x00100000) {
if((hx|lx)==0)
return FP_ILOGB0;
else /* subnormal x */
if(hx==0) {
for (ix = -1043; lx>0; lx<<=1) ix -=1;
} else {
for (ix = -1022,hx<<=11; hx>0; hx<<=1) ix -=1;
}
return ix;
}
else if (hx<0x7ff00000) return (hx>>20)-1023;
else if (hx>0x7ff00000 || lx!=0) return FP_ILOGBNAN;
else return INT_MAX;
}