/* @(#)s_ceil.c 5.1 93/09/24 */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice * is preserved. * ==================================================== */ #include #if defined(LIBM_SCCS) && !defined(lint) __RCSID("\$NetBSD: s_ceil.c,v 1.13.6.1 2014/05/22 11:36:57 yamt Exp \$"); #endif /* * ceil(x) * Return x rounded toward -inf to integral value * Method: * Bit twiddling. * Exception: * Inexact flag raised if x not equal to ceil(x). */ #include "math.h" #include "math_private.h" static const double huge = 1.0e300; #ifndef __HAVE_LONG_DOUBLE __strong_alias(_ceill, ceil) __weak_alias(ceill, ceil) #endif double ceil(double x) { int32_t i0,i1,jj0; u_int32_t i,j; EXTRACT_WORDS(i0,i1,x); jj0 = ((i0>>20)&0x7ff)-0x3ff; if(jj0<20) { if(jj0<0) { /* raise inexact if x != 0 */ if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ if(i0<0) {i0=0x80000000;i1=0;} else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;} } } else { i = (0x000fffff)>>jj0; if(((i0&i)|i1)==0) return x; /* x is integral */ if(huge+x>0.0) { /* raise inexact flag */ if(i0>0) i0 += (0x00100000)>>jj0; i0 &= (~i); i1=0; } } } else if (jj0>51) { if(jj0==0x400) return x+x; /* inf or NaN */ else return x; /* x is integral */ } else { i = ((u_int32_t)(0xffffffff))>>(jj0-20); if((i1&i)==0) return x; /* x is integral */ if(huge+x>0.0) { /* raise inexact flag */ if(i0>0) { if(jj0==20) i0+=1; else { j = i1 + (1<<(52-jj0)); if(j<(u_int32_t)i1) i0+=1; /* got a carry */ i1 = j; } } i1 &= (~i); } } INSERT_WORDS(x,i0,i1); return x; }