/* frexp.c - frexp math routine *//* Copyright 1992-1996 Wind River Systems, Inc. *//*modification history--------------------01j,23may01,to   doc fix01i,05feb99,dgp  document errno values01h,05aug96,dbt  frexp now returned a value >= 0.5 and strictly less than 1.0.		 (SPR #4280).		 Updated copyright.01g,05feb93,jdi  doc changes based on kdl review.01f,02dec92,jdi  doc tweaks.01e,28oct92,jdi  documentation cleanup.01d,21sep92,smb  replaced orignal versions.01c,20sep92,smb  documentation additions01b,30jul92,kdl  replaced routine contents with frexp() from floatLib.c.01a,08jul92,smb  written, documentation.*//*DESCRIPTIONSEE ALSO: American National Standard X3.159-1989NOMANUAL*/#include "math.h"#include "stddef.h"#include "errno.h"#include "private/mathP.h"/********************************************************************************* frexp - break a floating-point number into a normalized fraction and power of 2 (ANSI)** This routine breaks a double-precision number <value> into a normalized* fraction and integral power of 2.  It stores the integer exponent in <pexp>.** INCLUDE FILES: math.h** RETURNS: * The double-precision value <x>, such that the magnitude of <x> is* in the interval [1/2,1) or zero, and <value> equals <x> times* 2 to the power of <pexp>. If <value> is zero, both parts of the result* are zero.* * ERRNO: EDOM**/double frexp    (    double value,	/* number to be normalized */    int *pexp   	/* pointer to the exponent */    )    {    double r;    *pexp = 0;    /* determine number type */    switch (fpTypeGet(value, &r))	      	{        case NAN:		/* NOT A NUMBER */    	case INF:		/* INFINITE */            errno = EDOM;	    return (value);    	case ZERO:		/* ZERO */	    return (0.0);	default:	    /*	     * return value must be strictly less than 1.0 and >=0.5 .	     */	    if ((r = fabs(value)) >= 1.0)	        for(; (r >= 1.0); (*pexp)++, r /= 2.0);	    else	        for(; (r < 0.5); (*pexp)--, r *= 2.0);	    return (value < 0 ? -r : r);        }    }