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# define TGSOURCE "exp.c"
#include <errno.h>
#include <math.h>
#include "_tgmath.h"
/** exponential function **/
TYPE TGFN(exp)(TYPE x)
{
int MAXLOOPS = 10;
int i;
int factorial = 1;
TYPE exponent = 1.0;
TYPE power = 1.0;
switch (fpclassify(x)) {
case FP_ZERO: return 1.0;
case FP_INFINITE: return signbit(x) ? 0.0 : x;
default: break;
}
if (0) {
errno = ERANGE; /* The magnitude of ARGUMENT(x) is too large */
/* RETURN_FAILURE(CONSTANT(HUGE_VAL), A range error occurred); */
return TGHUGE;
}
/* TODO: tweak max loops */
/* exp x = 1 + x + x^2/2! + x^3/3! + x^4/4! ... */
for (i = 1; i < MAXLOOPS; i++) {
power *= x;
factorial *= i;
exponent += power / factorial;
}
/* RETURN_SUCCESS(the exponential function of ARGUMENT(x)); */
return exponent;
}
/***
compute the exponential function of ARGUMENT(x).
***/
/*
IMPLEMENTATION(The value returned on a domain error, CONSTANT(HUGE_VAL))
LINK(m)
STDC(1)
*/
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