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Diffstat (limited to 'newlib/libm/math/w_exp.c')
-rw-r--r--newlib/libm/math/w_exp.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/newlib/libm/math/w_exp.c b/newlib/libm/math/w_exp.c
new file mode 100644
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+++ b/newlib/libm/math/w_exp.c
@@ -0,0 +1,136 @@
+
+/* @(#)w_exp.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+FUNCTION
+ <<exp>>, <<expf>>---exponential
+INDEX
+ exp
+INDEX
+ expf
+
+ANSI_SYNOPSIS
+ #include <math.h>
+ double exp(double <[x]>);
+ float expf(float <[x]>);
+
+TRAD_SYNOPSIS
+ #include <math.h>
+ double exp(<[x]>);
+ double <[x]>;
+
+ float expf(<[x]>);
+ float <[x]>;
+
+DESCRIPTION
+ <<exp>> and <<expf>> calculate the exponential of <[x]>, that is,
+ @ifinfo
+ e raised to the power <[x]> (where e
+ @end ifinfo
+ @tex
+ $e^x$ (where $e$
+ @end tex
+ is the base of the natural system of logarithms, approximately 2.71828).
+
+ You can use the (non-ANSI) function <<matherr>> to specify
+ error handling for these functions.
+
+RETURNS
+ On success, <<exp>> and <<expf>> return the calculated value.
+ If the result underflows, the returned value is <<0>>. If the
+ result overflows, the returned value is <<HUGE_VAL>>. In
+ either case, <<errno>> is set to <<ERANGE>>.
+
+PORTABILITY
+ <<exp>> is ANSI C. <<expf>> is an extension.
+
+*/
+
+/*
+ * wrapper exp(x)
+ */
+
+#include "fdlibm.h"
+#include <errno.h>
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+static const double
+#else
+static double
+#endif
+o_threshold= 7.09782712893383973096e+02, /* 0x40862E42, 0xFEFA39EF */
+u_threshold= -7.45133219101941108420e+02; /* 0xc0874910, 0xD52D3051 */
+
+#ifdef __STDC__
+ double exp(double x) /* wrapper exp */
+#else
+ double exp(x) /* wrapper exp */
+ double x;
+#endif
+{
+#ifdef _IEEE_LIBM
+ return __ieee754_exp(x);
+#else
+ double z;
+ struct exception exc;
+ z = __ieee754_exp(x);
+ if(_LIB_VERSION == _IEEE_) return z;
+ if(finite(x)) {
+ if(x>o_threshold) {
+ /* exp(finite) overflow */
+#ifndef HUGE_VAL
+#define HUGE_VAL inf
+ double inf = 0.0;
+
+ SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
+#endif
+ exc.type = OVERFLOW;
+ exc.name = "exp";
+ exc.err = 0;
+ exc.arg1 = exc.arg2 = x;
+ if (_LIB_VERSION == _SVID_)
+ exc.retval = HUGE;
+ else
+ exc.retval = HUGE_VAL;
+ if (_LIB_VERSION == _POSIX_)
+ errno = ERANGE;
+ else if (!matherr(&exc)) {
+ errno = ERANGE;
+ }
+ if (exc.err != 0)
+ errno = exc.err;
+ return exc.retval;
+ } else if(x<u_threshold) {
+ /* exp(finite) underflow */
+ exc.type = UNDERFLOW;
+ exc.name = "exp";
+ exc.err = 0;
+ exc.arg1 = exc.arg2 = x;
+ exc.retval = 0.0;
+ if (_LIB_VERSION == _POSIX_)
+ errno = ERANGE;
+ else if (!matherr(&exc)) {
+ errno = ERANGE;
+ }
+ if (exc.err != 0)
+ errno = exc.err;
+ return exc.retval;
+ }
+ }
+ return z;
+#endif
+}
+
+#endif /* defined(_DOUBLE_IS_32BITS) */