1 /* s_ilogbl.c -- long double version of s_ilogb.c. 2 * Conversion to 80-bit long double by Mark Kettenis, kettenis@openbsd.org. 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 /* ilogbl(long double x) 17 * return the binary exponent of non-zero x 18 * ilogb(0) = FP_ILOGB0 19 * ilogb(NaN) = FP_ILOGBNAN (no signal is raised) 20 * ilogb(inf) = INT_MAX (no signal is raised) 21 */ 22 23 #include <float.h> 24 #include <math.h> 25 26 #include "math_private.h" 27 28 int 29 ilogbl(long double x) 30 { 31 int32_t esx,hx,lx,ix; 32 33 GET_LDOUBLE_WORDS(esx,hx,lx,x); 34 esx &= 0x7fff; 35 if(esx==0) { 36 if((hx|lx)==0) 37 return FP_ILOGB0; /* ilogb(0) = FP_ILOGB0 */ 38 else /* subnormal x */ 39 if(hx==0) { 40 for (ix = -16414; lx>0; lx<<=1) ix -=1; 41 } else { 42 for (ix = -16382; hx>0; hx<<=1) ix -=1; 43 } 44 return ix; 45 } 46 else if (esx<0x7fff) return (esx)-16383; 47 else if ((hx&0x7fffffff|lx)!=0) return FP_ILOGBNAN; 48 else return INT_MAX; 49 } 50 DEF_STD(ilogbl); 51