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- /*
- * ====================================================
- * 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.
- * ====================================================
- */
- /*
- * 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 <features.h>
- /* Prevent math.h from defining a colliding inline */
- #undef __USE_EXTERN_INLINES
- #include "math.h"
- #include "math_private.h"
- static const double huge = 1.0e300;
- double ceil(double x)
- {
- int32_t i0,i1,_j0;
- u_int32_t i,j;
- EXTRACT_WORDS(i0,i1,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=0x80000000;i1=0;}
- else if((i0|i1)!=0) { i0=0x3ff00000;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 = ((u_int32_t)(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);
- }
- }
- INSERT_WORDS(x,i0,i1);
- return x;
- }
- libm_hidden_def(ceil)
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