1 /* ilogbq.c -- __float128 version of s_ilogb.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: $";
20 /* ilogbl(__float128 x)
21 * return the binary exponent of non-zero x
22 * ilogbl(0) = FP_ILOGB0
23 * ilogbl(NaN) = FP_ILOGBNAN (no signal is raised)
24 * ilogbl(+-Inf) = INT_MAX (no signal is raised)
30 #include "quadmath-imp.h"
33 # define FP_ILOGB0 INT_MIN
36 # define FP_ILOGBNAN INT_MAX
45 GET_FLT128_WORDS64(hx,lx,x);
46 hx &= 0x7fffffffffffffffLL;
47 if(hx <= 0x0001000000000000LL) {
52 feraiseexcept (FE_INVALID);
54 return FP_ILOGB0; /* ilogbl(0) = FP_ILOGB0 */
56 else /* subnormal x */
58 for (ix = -16431; lx>0; lx<<=1) ix -=1;
60 for (ix = -16382, hx<<=15; hx>0; hx<<=1) ix -=1;
64 else if (hx<0x7fff000000000000LL) return (hx>>48)-0x3fff;
65 else if (FP_ILOGBNAN != INT_MAX) {
66 /* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */
67 if (((hx^0x7fff000000000000LL)|lx) == 0)
71 feraiseexcept (FE_INVALID);
79 feraiseexcept (FE_INVALID);