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authorimp <imp@FreeBSD.org>2012-10-22 13:20:31 +0000
committerimp <imp@FreeBSD.org>2012-10-22 13:20:31 +0000
commit3896267af2a650940674384d2ef0faa831cae76d (patch)
treee3a042777c0b002f1a54b8f865beaef7fd915bc8 /lib/msun
parent92f340b6e7dc02801983812c792c7d3964d31ef7 (diff)
downloadFreeBSD-src-3896267af2a650940674384d2ef0faa831cae76d.zip
FreeBSD-src-3896267af2a650940674384d2ef0faa831cae76d.tar.gz
Revert r241755
Diffstat (limited to 'lib/msun')
-rw-r--r--lib/msun/src/e_logf.c51
1 files changed, 0 insertions, 51 deletions
diff --git a/lib/msun/src/e_logf.c b/lib/msun/src/e_logf.c
index 77fe479..c3be6ed 100644
--- a/lib/msun/src/e_logf.c
+++ b/lib/msun/src/e_logf.c
@@ -19,57 +19,6 @@ __FBSDID("$FreeBSD$");
#include "math.h"
#include "math_private.h"
-/* __ieee754_log(x)
- * Return the logrithm of x
- *
- * Method :
- * 1. Argument Reduction: find k and f such that
- * x = 2^k * (1+f),
- * where sqrt(2)/2 < 1+f < sqrt(2) .
- *
- * 2. Approximation of log(1+f).
- * Let s = f/(2+f) ; based on log(1+f) = log(1+s) - log(1-s)
- * = 2s + 2/3 s**3 + 2/5 s**5 + .....,
- * = 2s + s*R
- * We use a special Reme algorithm on [0,0.1716] to generate
- * a polynomial of degree 8 to approximate R The maximum error
- * of this polynomial approximation is bounded by 2**-34.24. In
- * other words,
- * 2 4 6 8
- * R(z) ~ Lg1*s +Lg2*s +Lg3*s +Lg4*s
- * (the values of Lg1 to Lg7 are listed in the program)
- * and
- * | 2 8 | -34.24
- * | Lg1*s +...+Lg4*s - R(z) | <= 2
- * | |
- * Note that 2s = f - s*f = f - hfsq + s*hfsq, where hfsq = f*f/2.
- * In order to guarantee error in log below 1ulp, we compute log
- * by
- * log(1+f) = f - s*(f - R) (if f is not too large)
- * log(1+f) = f - (hfsq - s*(hfsq+R)). (better accuracy)
- *
- * 3. Finally, log(x) = k*ln2 + log(1+f).
- * = k*ln2_hi+(f-(hfsq-(s*(hfsq+R)+k*ln2_lo)))
- * Here ln2 is split into two floating point number:
- * ln2_hi + ln2_lo,
- * where n*ln2_hi is always exact for |n| < 2000.
- *
- * Special cases:
- * log(x) is NaN with signal if x < 0 (including -INF) ;
- * log(+INF) is +INF; log(0) is -INF with signal;
- * log(NaN) is that NaN with no signal.
- *
- * Accuracy:
- * according to an error analysis, the error is always less than
- * 1 ulp (unit in the last place).
- *
- * 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
ln2_hi = 6.9313812256e-01, /* 0x3f317180 */
ln2_lo = 9.0580006145e-06, /* 0x3717f7d1 */
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