53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
/* @(#)s_ceil.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/*
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* ceil(x)
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* Return x rounded toward -inf to integral value
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* Method:
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* Bit twiddling.
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*/
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#define NO_MATH_REDIRECT
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#include <math.h>
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#include <math_private.h>
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#include <libm-alias-double.h>
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double
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__ceil(double x)
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{
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int64_t i0,i;
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int32_t j0;
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EXTRACT_WORDS64(i0,x);
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j0 = ((i0>>52)&0x7ff)-0x3ff;
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if(j0<=51) {
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if(j0<0) {
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/* return 0*sign(x) if |x|<1 */
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if(i0<0) {i0=INT64_C(0x8000000000000000);}
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else if(i0!=0) { i0=INT64_C(0x3ff0000000000000);}
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} else {
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i = INT64_C(0x000fffffffffffff)>>j0;
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if((i0&i)==0) return x; /* x is integral */
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if(i0>0) i0 += UINT64_C(0x0010000000000000)>>j0;
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i0 &= (~i);
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}
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} else {
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if(j0==0x400) return x+x; /* inf or NaN */
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else return x; /* x is integral */
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}
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INSERT_WORDS64(x,i0);
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return x;
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}
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#ifndef __ceil
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libm_alias_double (__ceil, ceil)
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#endif
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