w_expf.c (1264B)
1 /* w_expf.c -- float version of w_exp.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 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 #ifndef lint 17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/w_expf.c,v 1.7 2002/05/28 18:15:04 alfred Exp $"; 18 #endif 19 20 /* 21 * wrapper expf(x) 22 */ 23 24 #include "math.h" 25 #include "math_private.h" 26 27 static const float 28 o_threshold= 8.8721679688e+01, /* 0x42b17180 */ 29 u_threshold= -1.0397208405e+02; /* 0xc2cff1b5 */ 30 31 float 32 expf(float x) /* wrapper expf */ 33 { 34 #ifdef _IEEE_LIBM 35 return __ieee754_expf(x); 36 #else 37 float z; 38 z = __ieee754_expf(x); 39 if(_LIB_VERSION == _IEEE_) return z; 40 if(finitef(x)) { 41 if(x>o_threshold) 42 /* exp overflow */ 43 return (float)__kernel_standard((double)x,(double)x,106); 44 else if(x<u_threshold) 45 /* exp underflow */ 46 return (float)__kernel_standard((double)x,(double)x,107); 47 } 48 return z; 49 #endif 50 }