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 #ifndef _IEEE_LIBM 24 #ifdef __STDC__ 25 static const float 26 #else 27 static float 28 #endif 29 o_threshold= 8.8721679688e+01, /* 0x42b17180 */ 30 u_threshold= -1.0397208405e+02; /* 0xc2cff1b5 */ 31 #endif 32 33 #ifdef __STDC__ expf(float x)34 float expf(float x) /* wrapper expf */ 35 #else 36 float expf(x) /* wrapper expf */ 37 float x; 38 #endif 39 { 40 #ifdef _IEEE_LIBM 41 return __ieee754_expf(x); 42 #else 43 float z; 44 struct exception exc; 45 z = __ieee754_expf(x); 46 if(_LIB_VERSION == _IEEE_) return z; 47 if(finitef(x)) { 48 if(x>o_threshold) { 49 /* expf(finite) overflow */ 50 #ifndef HUGE_VAL 51 #define HUGE_VAL inf 52 double inf = 0.0; 53 54 SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ 55 #endif 56 exc.type = OVERFLOW; 57 exc.name = "expf"; 58 exc.err = 0; 59 exc.arg1 = exc.arg2 = (double)x; 60 if (_LIB_VERSION == _SVID_) 61 exc.retval = HUGE; 62 else 63 exc.retval = HUGE_VAL; 64 if (_LIB_VERSION == _POSIX_) 65 errno = ERANGE; 66 else if (!matherr(&exc)) { 67 errno = ERANGE; 68 } 69 if (exc.err != 0) 70 errno = exc.err; 71 return exc.retval; 72 } else if(x<u_threshold) { 73 /* expf(finite) underflow */ 74 exc.type = UNDERFLOW; 75 exc.name = "expf"; 76 exc.err = 0; 77 exc.arg1 = exc.arg2 = (double)x; 78 exc.retval = 0.0; 79 if (_LIB_VERSION == _POSIX_) 80 errno = ERANGE; 81 else if (!matherr(&exc)) { 82 errno = ERANGE; 83 } 84 if (exc.err != 0) 85 errno = exc.err; 86 return exc.retval; 87 } 88 } 89 return z; 90 #endif 91 } 92 93 #ifdef _DOUBLE_IS_32BITS 94 95 #ifdef __STDC__ exp(double x)96 double exp(double x) 97 #else 98 double exp(x) 99 double x; 100 #endif 101 { 102 return (double) expf((float) x); 103 } 104 105 #endif /* defined(_DOUBLE_IS_32BITS) */ 106