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/* @(#)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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* ceill(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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* Exception: |
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* Inexact flag raised if x not equal to ceil(x). |
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*/ |
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#include <math.h> |
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#include "math_private.h" |
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static const long double huge = 1.0e4930L; |
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long double |
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ceill(long double x) |
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{ |
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int32_t i1,jj0; |
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u_int32_t i,j,se,i0,sx; |
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GET_LDOUBLE_WORDS(se,i0,i1,x); |
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sx = (se>>15)&1; |
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jj0 = (se&0x7fff)-0x3fff; |
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if(jj0<31) { |
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if(jj0<0) { /* raise inexact if x != 0 */ |
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if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ |
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if(sx) {se=0x8000;i0=0;i1=0;} |
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else if((i0|i1)!=0) { se=0x3fff;i0=0x80000000;i1=0;} |
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} |
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} else { |
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i = (0x7fffffff)>>jj0; |
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if(((i0&i)|i1)==0) return x; /* x is integral */ |
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if(huge+x>0.0) { /* raise inexact flag */ |
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if(sx==0) { |
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if (jj0>0 && (i0+(0x80000000>>jj0))>i0) |
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i0+=0x80000000>>jj0; |
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else |
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{ |
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i = 0x7fffffff; |
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++se; |
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} |
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} |
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i0 &= (~i); i1=0; |
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} |
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} |
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} else if (jj0>62) { |
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if(jj0==0x4000) return x+x; /* inf or NaN */ |
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else return x; /* x is integral */ |
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} else { |
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i = ((u_int32_t)(0xffffffff))>>(jj0-31); |
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if((i1&i)==0) return x; /* x is integral */ |
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if(huge+x>0.0) { /* raise inexact flag */ |
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if(sx==0) { |
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if(jj0==31) i0+=1; |
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else { |
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j = i1 + (1<<(63-jj0)); |
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if(j<i1) i0+=1; /* got a carry */ |
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i1 = j; |
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} |
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} |
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i1 &= (~i); |
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} |
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} |
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SET_LDOUBLE_WORDS(x,se,i0,i1); |
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return x; |
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} |