1 /* s_ilogbl.c -- long double version of s_ilogb.c. 2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. 3 */ 4 5 /* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 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 * ==================================================== 14 */ 15 16 #if defined(LIBM_SCCS) && !defined(lint) 17 static char rcsid[] = "$NetBSD: $"; 18 #endif 19 20 /* ilogbl(long double 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) 25 */ 26 27 #include <math.h> 28 #include "quadmath-imp.h" 29 #ifndef FP_ILOGB0 30 # define FP_ILOGB0 INT_MIN 31 #endif 32 #ifndef FP_ILOGBNAN 33 # define FP_ILOGBNAN INT_MAX 34 #endif 35 36 int ilogbq (__float128 x) 37 { 38 int64_t hx,lx; 39 int ix; 40 41 GET_FLT128_WORDS64(hx,lx,x); 42 hx &= 0x7fffffffffffffffLL; 43 if(hx <= 0x0001000000000000LL) { 44 if((hx|lx)==0) 45 { errno = EDOM; feraiseexcept (FE_INVALID); return FP_ILOGB0; } /* ilogbl(0) = FP_ILOGB0 */ 46 else /* subnormal x */ 47 if(hx==0) { 48 for (ix = -16431; lx>0; lx<<=1) ix -=1; 49 } else { 50 for (ix = -16382, hx<<=15; hx>0; hx<<=1) ix -=1; hypotq(__float128 x,__float128 y)51 } 52 return ix; 53 } 54 else if (hx<0x7fff000000000000LL) return (hx>>48)-0x3fff; 55 else if (FP_ILOGBNAN != INT_MAX) { 56 /* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */ 57 if (((hx^0x7fff000000000000LL)|lx) == 0) 58 { errno = EDOM; feraiseexcept (FE_INVALID); return INT_MAX; } 59 } 60 { errno = EDOM; feraiseexcept (FE_INVALID); return FP_ILOGBNAN; } 61 } 62