1 /* @(#)w_exp.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 #include <sys/cdefs.h> 14 #if defined(LIBM_SCCS) && !defined(lint) 15 __RCSID("$NetBSD: w_exp.c,v 1.8 1999/07/02 15:37:44 simonb Exp $"); 16 #endif 17 18 /* 19 * wrapper exp(x) 20 */ 21 22 #include "math.h" 23 #include "math_private.h" 24 25 #ifdef __STDC__ 26 static const double 27 #else 28 static double 29 #endif 30 o_threshold= 7.09782712893383973096e+02, /* 0x40862E42, 0xFEFA39EF */ 31 u_threshold= -7.45133219101941108420e+02; /* 0xc0874910, 0xD52D3051 */ 32 33 #ifdef __STDC__ 34 double exp(double x) /* wrapper exp */ 35 #else 36 double exp(x) /* wrapper exp */ 37 double x; 38 #endif 39 { 40 #ifdef _IEEE_LIBM 41 return __ieee754_exp(x); 42 #else 43 double z; 44 z = __ieee754_exp(x); 45 if(_LIB_VERSION == _IEEE_) return z; 46 if(finite(x)) { 47 if(x>o_threshold) 48 return __kernel_standard(x,x,6); /* exp overflow */ 49 else if(x<u_threshold) 50 return __kernel_standard(x,x,7); /* exp underflow */ 51 } 52 return z; 53 #endif 54 } 55