Standard Libraries for EDK II.

[mirror_edk2.git] / StdLib / LibC / Math / s_ceil.c

/* @(#)s_ceil.c 5.1 93/09/24 */\r
/*\r
 * ====================================================\r
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.\r
 *\r
 * Developed at SunPro, a Sun Microsystems, Inc. business.\r
 * Permission to use, copy, modify, and distribute this\r
 * software is freely granted, provided that this notice\r
 * is preserved.\r
 * ====================================================\r
 */\r
#include  <LibConfig.h>\r
#include  <sys/EfiCdefs.h>\r
#if defined(LIBM_SCCS) && !defined(lint)\r
__RCSID("$NetBSD: s_ceil.c,v 1.11 2002/05/26 22:01:54 wiz Exp $");\r
#endif\r
\r
/*\r
 * ceil(x)\r
 * Return x rounded toward -inf to integral value\r
 * Method:\r
 *  Bit twiddling.\r
 * Exception:\r
 *  Inexact flag raised if x not equal to ceil(x).\r
 */\r
\r
#include "math.h"\r
#include "math_private.h"\r
\r
static const double huge = 1.0e300;\r
\r
double\r
ceil(double x)\r
{\r
  int32_t i0,i1,j0;\r
  u_int32_t i,j;\r
\r
  EXTRACT_WORDS(i0,i1,x);\r
  j0 = ((i0>>20)&0x7ff)-0x3ff;\r
  if(j0<20) {\r
      if(j0<0) {  /* raise inexact if x != 0 */\r
    if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */\r
        if(i0<0) {i0=0x80000000;i1=0;}\r
        else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;}\r
    }\r
      } else {\r
    i = (0x000fffff)>>j0;\r
    if(((i0&i)|i1)==0) return x; /* x is integral */\r
    if(huge+x>0.0) {  /* raise inexact flag */\r
        if(i0>0) i0 += (0x00100000)>>j0;\r
        i0 &= (~i); i1=0;\r
    }\r
      }\r
  } else if (j0>51) {\r
      if(j0==0x400) return x+x; /* inf or NaN */\r
      else return x;    /* x is integral */\r
  } else {\r
      i = ((u_int32_t)(0xffffffff))>>(j0-20);\r
      if((i1&i)==0) return x; /* x is integral */\r
      if(huge+x>0.0) {    /* raise inexact flag */\r
    if(i0>0) {\r
        if(j0==20) i0+=1;\r
        else {\r
      j = i1 + (1<<(52-j0));\r
      if((int32_t)j<i1) i0+=1; /* got a carry */\r
      i1 = j;\r
        }\r
    }\r
    i1 &= (~i);\r
      }\r
  }\r
  INSERT_WORDS(x,i0,i1);\r
  return x;\r
}\r