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authorimp <imp@FreeBSD.org>2012-10-22 13:21:11 +0000
committerimp <imp@FreeBSD.org>2012-10-22 13:21:11 +0000
commitf9a05f9a0a07c02f6cb54808ae52eef16ee600df (patch)
treedcfde716e825dca2dc349ddef1b51df367fcc5e1 /lib/msun
parent3896267af2a650940674384d2ef0faa831cae76d (diff)
downloadFreeBSD-src-f9a05f9a0a07c02f6cb54808ae52eef16ee600df.zip
FreeBSD-src-f9a05f9a0a07c02f6cb54808ae52eef16ee600df.tar.gz
Revert r241756
Diffstat (limited to 'lib/msun')
-rw-r--r--lib/msun/src/e_expf.c62
1 files changed, 0 insertions, 62 deletions
diff --git a/lib/msun/src/e_expf.c b/lib/msun/src/e_expf.c
index 432eaa2..a479076 100644
--- a/lib/msun/src/e_expf.c
+++ b/lib/msun/src/e_expf.c
@@ -21,68 +21,6 @@ __FBSDID("$FreeBSD$");
#include "math.h"
#include "math_private.h"
-/* __ieee754_expf
- * Returns the exponential of x.
- *
- * Method
- * 1. Argument reduction:
- * Reduce x to an r so that |r| <= 0.5*ln2 ~ 0.34658.
- * Given x, find r and integer k such that
- *
- * x = k*ln2 + r, |r| <= 0.5*ln2.
- *
- * Here r will be represented as r = hi-lo for better
- * accuracy.
- *
- * 2. Approximation of exp(r) by a special rational function on
- * the interval [0,0.34658]:
- * Write
- * R(r**2) = r*(exp(r)+1)/(exp(r)-1) = 2 + r*r/6 - r**4/360 + ...
- * We use a special Remes algorithm on [0,0.34658] to generate
- * a polynomial of degree 2 to approximate R. The maximum error
- * of this polynomial approximation is bounded by 2**-27. In
- * other words,
- * R(z) ~ 2.0 + P1*z + P2*z*z
- * (where z=r*r, and the values of P1 and P2 are listed below)
- * and
- * | 2 | -27
- * | 2.0+P1*z+P2*z - R(z) | <= 2
- * | |
- * The computation of expf(r) thus becomes
- * 2*r
- * expf(r) = 1 + -------
- * R - r
- * r*R1(r)
- * = 1 + r + ----------- (for better accuracy)
- * 2 - R1(r)
- * where
- * 2 4
- * R1(r) = r - (P1*r + P2*r)
- *
- * 3. Scale back to obtain expf(x):
- * From step 1, we have
- * expf(x) = 2^k * expf(r)
- *
- * Special cases:
- * expf(INF) is INF, exp(NaN) is NaN;
- * expf(-INF) is 0, and
- * for finite argument, only exp(0)=1 is exact.
- *
- * Accuracy:
- * according to an error analysis, the error is always less than
- * 0.5013 ulp (unit in the last place).
- *
- * Misc. info.
- * For IEEE float
- * if x > 8.8721679688e+01 then exp(x) overflow
- * if x < -1.0397208405e+02 then exp(x) underflow
- *
- * Constants:
- * The hexadecimal values are the intended ones for the following
- * constants. The decimal values may be used, provided that the
- * compiler will convert from decimal to binary accurately enough
- * to produce the hexadecimal values shown.
- */
static const float
one = 1.0,
halF[2] = {0.5,-0.5,},
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