/* derived from /netlib/fdlibm */ /* @(#)s_floor.c 1.3 95/01/18 *//* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunSoft, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice  * is preserved. * ==================================================== */ /* * floor(x) * Return x rounded toward -inf to integral value * Method: *	Bit twiddling. * Exception: *	Inexact flag raised if x not equal to floor(x). */ #include "fdlibm.h" static const double Huge = 1.0e300; 	double floor(double x){	int i0,i1,j0;	unsigned i,j;	i0 =  __HI(x);	i1 =  __LO(x);	j0 = ((i0>>20)&0x7ff)-0x3ff;	if(j0<20) {	    if(j0<0) { 	/* raise inexact if x != 0 */		if(Huge+x>0.0) {/* return 0*sign(x) if |x|<1 */		    if(i0>=0) {i0=i1=0;} 		    else if(((i0&0x7fffffff)|i1)!=0)			{ i0=0xbff00000;i1=0;}		}	    } else {		i = (0x000fffff)>>j0;		if(((i0&i)|i1)==0) return x; /* x is integral */		if(Huge+x>0.0) {	/* raise inexact flag */		    if(i0<0) i0 += (0x00100000)>>j0;		    i0 &= (~i); i1=0;		}	    }	} else if (j0>51) {	    if(j0==0x400) return x+x;	/* inf or NaN */	    else return x;		/* x is integral */	} else {	    i = ((unsigned)(0xffffffff))>>(j0-20);	    if((i1&i)==0) return x;	/* x is integral */	    if(Huge+x>0.0) { 		/* raise inexact flag */		if(i0<0) {		    if(j0==20) i0+=1; 		    else {			j = i1+(1<<(52-j0));			if(j<i1) i0 +=1 ; 	/* got a carry */			i1=j;		    }		}		i1 &= (~i);	    }	}	__HI(x) = i0;	__LO(x) = i1;	return x;}