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-rw-r--r--libm/float/asinf.c186
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diff --git a/libm/float/asinf.c b/libm/float/asinf.c
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--- a/libm/float/asinf.c
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-/* asinf.c
- *
- * Inverse circular sine
- *
- *
- *
- * SYNOPSIS:
- *
- * float x, y, asinf();
- *
- * y = asinf( x );
- *
- *
- *
- * DESCRIPTION:
- *
- * Returns radian angle between -pi/2 and +pi/2 whose sine is x.
- *
- * A polynomial of the form x + x**3 P(x**2)
- * is used for |x| in the interval [0, 0.5]. If |x| > 0.5 it is
- * transformed by the identity
- *
- * asin(x) = pi/2 - 2 asin( sqrt( (1-x)/2 ) ).
- *
- *
- * ACCURACY:
- *
- * Relative error:
- * arithmetic domain # trials peak rms
- * IEEE -1, 1 100000 2.5e-7 5.0e-8
- *
- *
- * ERROR MESSAGES:
- *
- * message condition value returned
- * asinf domain |x| > 1 0.0
- *
- */
- /* acosf()
- *
- * Inverse circular cosine
- *
- *
- *
- * SYNOPSIS:
- *
- * float x, y, acosf();
- *
- * y = acosf( x );
- *
- *
- *
- * DESCRIPTION:
- *
- * Returns radian angle between -pi/2 and +pi/2 whose cosine
- * is x.
- *
- * Analytically, acos(x) = pi/2 - asin(x). However if |x| is
- * near 1, there is cancellation error in subtracting asin(x)
- * from pi/2. Hence if x < -0.5,
- *
- * acos(x) = pi - 2.0 * asin( sqrt((1+x)/2) );
- *
- * or if x > +0.5,
- *
- * acos(x) = 2.0 * asin( sqrt((1-x)/2) ).
- *
- *
- * ACCURACY:
- *
- * Relative error:
- * arithmetic domain # trials peak rms
- * IEEE -1, 1 100000 1.4e-7 4.2e-8
- *
- *
- * ERROR MESSAGES:
- *
- * message condition value returned
- * acosf domain |x| > 1 0.0
- */
-
-/* asin.c */
-
-/*
-Cephes Math Library Release 2.2: June, 1992
-Copyright 1984, 1987, 1992 by Stephen L. Moshier
-Direct inquiries to 30 Frost Street, Cambridge, MA 02140
-*/
-
-/* Single precision circular arcsine
- * test interval: [-0.5, +0.5]
- * trials: 10000
- * peak relative error: 6.7e-8
- * rms relative error: 2.5e-8
- */
-#include <math.h>
-extern float PIF, PIO2F;
-
-float sqrtf( float );
-
-float asinf( float xx )
-{
-float a, x, z;
-int sign, flag;
-
-x = xx;
-
-if( x > 0 )
- {
- sign = 1;
- a = x;
- }
-else
- {
- sign = -1;
- a = -x;
- }
-
-if( a > 1.0 )
- {
- mtherr( "asinf", DOMAIN );
- return( 0.0 );
- }
-
-if( a < 1.0e-4 )
- {
- z = a;
- goto done;
- }
-
-if( a > 0.5 )
- {
- z = 0.5 * (1.0 - a);
- x = sqrtf( z );
- flag = 1;
- }
-else
- {
- x = a;
- z = x * x;
- flag = 0;
- }
-
-z =
-(((( 4.2163199048E-2 * z
- + 2.4181311049E-2) * z
- + 4.5470025998E-2) * z
- + 7.4953002686E-2) * z
- + 1.6666752422E-1) * z * x
- + x;
-
-if( flag != 0 )
- {
- z = z + z;
- z = PIO2F - z;
- }
-done:
-if( sign < 0 )
- z = -z;
-return( z );
-}
-
-
-
-
-float acosf( float x )
-{
-
-if( x < -1.0 )
- goto domerr;
-
-if( x < -0.5)
- return( PIF - 2.0 * asinf( sqrtf(0.5*(1.0+x)) ) );
-
-if( x > 1.0 )
- {
-domerr: mtherr( "acosf", DOMAIN );
- return( 0.0 );
- }
-
-if( x > 0.5 )
- return( 2.0 * asinf( sqrtf(0.5*(1.0-x) ) ) );
-
-return( PIO2F - asinf(x) );
-}
-