1*627f7eb2Smrg /* s_ilogbl.c -- long double version of s_ilogb.c.
2*627f7eb2Smrg * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
3*627f7eb2Smrg */
4*627f7eb2Smrg
5*627f7eb2Smrg /*
6*627f7eb2Smrg * ====================================================
7*627f7eb2Smrg * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8*627f7eb2Smrg *
9*627f7eb2Smrg * Developed at SunPro, a Sun Microsystems, Inc. business.
10*627f7eb2Smrg * Permission to use, copy, modify, and distribute this
11*627f7eb2Smrg * software is freely granted, provided that this notice
12*627f7eb2Smrg * is preserved.
13*627f7eb2Smrg * ====================================================
14*627f7eb2Smrg */
15*627f7eb2Smrg
16*627f7eb2Smrg #if defined(LIBM_SCCS) && !defined(lint)
17*627f7eb2Smrg static char rcsid[] = "NetBSD: ";
18*627f7eb2Smrg #endif
19*627f7eb2Smrg
20*627f7eb2Smrg /* ilogbl(long double x)
21*627f7eb2Smrg * return the binary exponent of non-zero x
22*627f7eb2Smrg * ilogbl(0) = FP_ILOGB0
23*627f7eb2Smrg * ilogbl(NaN) = FP_ILOGBNAN (no signal is raised)
24*627f7eb2Smrg * ilogbl(+-Inf) = INT_MAX (no signal is raised)
25*627f7eb2Smrg */
26*627f7eb2Smrg
27*627f7eb2Smrg #include <math.h>
28*627f7eb2Smrg #include "quadmath-imp.h"
29*627f7eb2Smrg #ifndef FP_ILOGB0
30*627f7eb2Smrg # define FP_ILOGB0 INT_MIN
31*627f7eb2Smrg #endif
32*627f7eb2Smrg #ifndef FP_ILOGBNAN
33*627f7eb2Smrg # define FP_ILOGBNAN INT_MAX
34*627f7eb2Smrg #endif
35*627f7eb2Smrg
ilogbq(__float128 x)36*627f7eb2Smrg int ilogbq (__float128 x)
37*627f7eb2Smrg {
38*627f7eb2Smrg int64_t hx,lx;
39*627f7eb2Smrg int ix;
40*627f7eb2Smrg
41*627f7eb2Smrg GET_FLT128_WORDS64(hx,lx,x);
42*627f7eb2Smrg hx &= 0x7fffffffffffffffLL;
43*627f7eb2Smrg if(hx <= 0x0001000000000000LL) {
44*627f7eb2Smrg if((hx|lx)==0)
45*627f7eb2Smrg { errno = EDOM; feraiseexcept (FE_INVALID); return FP_ILOGB0; } /* ilogbl(0) = FP_ILOGB0 */
46*627f7eb2Smrg else /* subnormal x */
47*627f7eb2Smrg if(hx==0) {
48*627f7eb2Smrg for (ix = -16431; lx>0; lx<<=1) ix -=1;
49*627f7eb2Smrg } else {
50*627f7eb2Smrg for (ix = -16382, hx<<=15; hx>0; hx<<=1) ix -=1;
51*627f7eb2Smrg }
52*627f7eb2Smrg return ix;
53*627f7eb2Smrg }
54*627f7eb2Smrg else if (hx<0x7fff000000000000LL) return (hx>>48)-0x3fff;
55*627f7eb2Smrg else if (FP_ILOGBNAN != INT_MAX) {
56*627f7eb2Smrg /* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */
57*627f7eb2Smrg if (((hx^0x7fff000000000000LL)|lx) == 0)
58*627f7eb2Smrg { errno = EDOM; feraiseexcept (FE_INVALID); return INT_MAX; }
59*627f7eb2Smrg }
60*627f7eb2Smrg { errno = EDOM; feraiseexcept (FE_INVALID); return FP_ILOGBNAN; }
61*627f7eb2Smrg }
62