e_acoshf.c - vx32 - Local 9vx git repository for patches.
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       ---
       e_acoshf.c (1379B)
       ---
            1 /* e_acoshf.c -- float version of e_acosh.c.
            2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
            3  */
            4 
            5 /*
            6  * ====================================================
            7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
            8  *
            9  * Developed at SunPro, a Sun Microsystems, Inc. business.
           10  * Permission to use, copy, modify, and distribute this
           11  * software is freely granted, provided that this notice
           12  * is preserved.
           13  * ====================================================
           14  */
           15 
           16 #ifndef lint
           17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_acoshf.c,v 1.7 2002/05/28 17:03:12 alfred Exp $";
           18 #endif
           19 
           20 #include "math.h"
           21 #include "math_private.h"
           22 
           23 static const float
           24 one        = 1.0,
           25 ln2        = 6.9314718246e-01;  /* 0x3f317218 */
           26 
           27 float
           28 __ieee754_acoshf(float x)
           29 {
           30         float t;
           31         int32_t hx;
           32         GET_FLOAT_WORD(hx,x);
           33         if(hx<0x3f800000) {                /* x < 1 */
           34             return (x-x)/(x-x);
           35         } else if(hx >=0x4d800000) {        /* x > 2**28 */
           36             if(hx >=0x7f800000) {        /* x is inf of NaN */
           37                 return x+x;
           38             } else
           39                 return __ieee754_logf(x)+ln2;        /* acosh(huge)=log(2x) */
           40         } else if (hx==0x3f800000) {
           41             return 0.0;                        /* acosh(1) = 0 */
           42         } else if (hx > 0x40000000) {        /* 2**28 > x > 2 */
           43             t=x*x;
           44             return __ieee754_logf((float)2.0*x-one/(x+__ieee754_sqrtf(t-one)));
           45         } else {                        /* 1<x<2 */
           46             t = x-one;
           47             return log1pf(t+__ieee754_sqrtf((float)2.0*t+t*t));
           48         }
           49 }