85 lines
1.7 KiB
C
85 lines
1.7 KiB
C
/* sf_rint.c -- float version of s_rint.c.
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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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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#include "fdlibm.h"
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#ifdef __STDC__
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static const float
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#else
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static float
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#endif
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TWO23[2]={
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8.3886080000e+06, /* 0x4b000000 */
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-8.3886080000e+06, /* 0xcb000000 */
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};
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#ifdef __STDC__
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float rintf(float x)
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#else
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float rintf(x)
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float x;
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#endif
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{
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__int32_t i0,j0,sx;
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__uint32_t i,i1,ix;
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float t;
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volatile float w;
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GET_FLOAT_WORD(i0,x);
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sx = (i0>>31)&1;
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ix = (i0&0x7fffffff);
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j0 = (ix>>23)-0x7f;
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if(j0<23) {
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if(FLT_UWORD_IS_ZERO(ix))
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return x;
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if(j0<0) {
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i1 = (i0&0x07fffff);
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i0 &= 0xfff00000;
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i0 |= ((i1|-i1)>>9)&0x400000;
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SET_FLOAT_WORD(x,i0);
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w = TWO23[sx]+x;
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t = w-TWO23[sx];
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GET_FLOAT_WORD(i0,t);
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SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
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return t;
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} else {
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i = (0x007fffff)>>j0;
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if((i0&i)==0) return x; /* x is integral */
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i>>=1;
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if((i0&i)!=0) i0 = (i0&(~i))|((0x200000)>>j0);
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}
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} else {
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if(!FLT_UWORD_IS_FINITE(ix)) return x+x; /* inf or NaN */
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else
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return x; /* x is integral */
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}
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SET_FLOAT_WORD(x,i0);
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w = TWO23[sx]+x;
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return w-TWO23[sx];
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}
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#ifdef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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double rint(double x)
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#else
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double rint(x)
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double x;
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#endif
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{
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return (double) rintf((float) x);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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