1 /* wf_exp.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 /* 17 * wrapper expf(x) 18 */ 19 20 #include "fdlibm.h" 21 #include <errno.h> 22 23 #ifdef __STDC__ 24 static const float 25 #else 26 static float 27 #endif 28 o_threshold= 8.8721679688e+01, /* 0x42b17180 */ 29 u_threshold= -1.0397208405e+02; /* 0xc2cff1b5 */ 30 31 #ifdef __STDC__ expf(float x)32 float expf(float x) /* wrapper expf */ 33 #else 34 float expf(x) /* wrapper expf */ 35 float x; 36 #endif 37 { 38 #ifdef _IEEE_LIBM 39 return __ieee754_expf(x); 40 #else 41 float z; 42 struct exception exc; 43 z = __ieee754_expf(x); 44 if(_LIB_VERSION == _IEEE_) return z; 45 if(finitef(x)) { 46 if(x>o_threshold) { 47 /* expf(finite) overflow */ 48 #ifndef HUGE_VAL 49 #define HUGE_VAL inf 50 double inf = 0.0; 51 52 SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ 53 #endif 54 exc.type = OVERFLOW; 55 exc.name = "expf"; 56 exc.err = 0; 57 exc.arg1 = exc.arg2 = (double)x; 58 if (_LIB_VERSION == _SVID_) 59 exc.retval = HUGE; 60 else 61 exc.retval = HUGE_VAL; 62 if (_LIB_VERSION == _POSIX_) 63 errno = ERANGE; 64 else if (!matherr(&exc)) { 65 errno = ERANGE; 66 } 67 if (exc.err != 0) 68 errno = exc.err; 69 return exc.retval; 70 } else if(x<u_threshold) { 71 /* expf(finite) underflow */ 72 exc.type = UNDERFLOW; 73 exc.name = "expf"; 74 exc.err = 0; 75 exc.arg1 = exc.arg2 = (double)x; 76 exc.retval = 0.0; 77 if (_LIB_VERSION == _POSIX_) 78 errno = ERANGE; 79 else if (!matherr(&exc)) { 80 errno = ERANGE; 81 } 82 if (exc.err != 0) 83 errno = exc.err; 84 return exc.retval; 85 } 86 } 87 return z; 88 #endif 89 } 90 91 #ifdef _DOUBLE_IS_32BITS 92 93 #ifdef __STDC__ exp(double x)94 double exp(double x) 95 #else 96 double exp(x) 97 double x; 98 #endif 99 { 100 return (double) expf((float) x); 101 } 102 103 #endif /* defined(_DOUBLE_IS_32BITS) */ 104