From 7ce331c01ce6eb7b3f5c715a38a24359da9c6ee2 Mon Sep 17 00:00:00 2001
From: Eric Andersen <andersen@codepoet.org>
Date: Thu, 22 Nov 2001 14:04:29 +0000
Subject: Totally rework the math library, this time based on the MacOs X math
 library (which is itself based on the math lib from FreeBSD).  -Erik

---
 libm/float/log2f.c | 129 -----------------------------------------------------
 1 file changed, 129 deletions(-)
 delete mode 100644 libm/float/log2f.c

(limited to 'libm/float/log2f.c')

diff --git a/libm/float/log2f.c b/libm/float/log2f.c
deleted file mode 100644
index 5cd5f4838..000000000
--- a/libm/float/log2f.c
+++ /dev/null
@@ -1,129 +0,0 @@
-/*							log2f.c
- *
- *	Base 2 logarithm
- *
- *
- *
- * SYNOPSIS:
- *
- * float x, y, log2f();
- *
- * y = log2f( x );
- *
- *
- *
- * DESCRIPTION:
- *
- * Returns the base 2 logarithm of x.
- *
- * The argument is separated into its exponent and fractional
- * parts.  If the exponent is between -1 and +1, the base e
- * logarithm of the fraction is approximated by
- *
- *     log(1+x) = x - 0.5 x**2 + x**3 P(x)/Q(x).
- *
- * Otherwise, setting  z = 2(x-1)/x+1),
- * 
- *     log(x) = z + z**3 P(z)/Q(z).
- *
- *
- *
- * ACCURACY:
- *
- *                      Relative error:
- * arithmetic   domain     # trials      peak         rms
- *    IEEE      exp(+-88)   100000      1.1e-7      2.4e-8
- *    IEEE      0.5, 2.0    100000      1.1e-7      3.0e-8
- *
- * In the tests over the interval [exp(+-88)], the logarithms
- * of the random arguments were uniformly distributed.
- *
- * ERROR MESSAGES:
- *
- * log singularity:  x = 0; returns MINLOGF/log(2)
- * log domain:       x < 0; returns MINLOGF/log(2)
- */
-
-/*
-Cephes Math Library Release 2.2:  June, 1992
-Copyright 1984, 1992 by Stephen L. Moshier
-Direct inquiries to 30 Frost Street, Cambridge, MA 02140
-*/
-
-#include <math.h>
-static char fname[] = {"log2"};
-
-/* Coefficients for log(1+x) = x - x**2/2 + x**3 P(x)
- * 1/sqrt(2) <= x < sqrt(2)
- */
-
-static float P[] = {
- 7.0376836292E-2,
--1.1514610310E-1,
- 1.1676998740E-1,
--1.2420140846E-1,
- 1.4249322787E-1,
--1.6668057665E-1,
- 2.0000714765E-1,
--2.4999993993E-1,
- 3.3333331174E-1
-};
-
-#define LOG2EA 0.44269504088896340735992
-#define SQRTH 0.70710678118654752440
-extern float MINLOGF, LOGE2F;
-
-float frexpf(float, int *), polevlf(float, float *, int);
-
-float log2f(float xx)
-{
-float x, y, z;
-int e;
-
-x = xx;
-/* Test for domain */
-if( x <= 0.0 )
-	{
-	if( x == 0.0 )
-		mtherr( fname, SING );
-	else
-		mtherr( fname, DOMAIN );
-	return( MINLOGF/LOGE2F );
-	}
-
-/* separate mantissa from exponent */
-x = frexpf( x, &e );
-
-
-/* logarithm using log(1+x) = x - .5x**2 + x**3 P(x)/Q(x) */
-
-if( x < SQRTH )
-	{
-	e -= 1;
-	x = 2.0*x - 1.0;
-	}	
-else
-	{
-	x = x - 1.0;
-	}
-
-z = x*x;
-y = x * ( z * polevlf( x, P, 8 ) );
-y = y - 0.5 * z;   /*  y - 0.5 * x**2  */
-
-
-/* Multiply log of fraction by log2(e)
- * and base 2 exponent by 1
- *
- * ***CAUTION***
- *
- * This sequence of operations is critical and it may
- * be horribly defeated by some compiler optimizers.
- */
-z = y * LOG2EA;
-z += x * LOG2EA;
-z += y;
-z += x;
-z += (float )e;
-return( z );
-}
-- 
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