70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
/* @(#)s_modf.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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* modfl(long double x, long double *iptr)
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* return fraction part of x, and return x's integral part in *iptr.
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* Method:
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* Bit twiddling.
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*
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* Exception:
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* No exception.
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*/
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#include <openlibm_math.h>
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#include "math_private.h"
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static const long double one = 1.0;
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long double
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modfl(long double x, long double *iptr)
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{
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int32_t i0,i1,jj0;
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u_int32_t i,se;
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GET_LDOUBLE_WORDS(se,i0,i1,x);
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jj0 = (se&0x7fff)-0x3fff; /* exponent of x */
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if(jj0<32) { /* integer part in high x */
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if(jj0<0) { /* |x|<1 */
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SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */
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return x;
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} else {
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i = (0x7fffffff)>>jj0;
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if(((i0&i)|i1)==0) { /* x is integral */
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*iptr = x;
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SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
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return x;
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} else {
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SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0);
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return x - *iptr;
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}
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}
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} else if (jj0>63) { /* no fraction part */
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*iptr = x*one;
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/* We must handle NaNs separately. */
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if (jj0 == 0x4000 && ((i0 & 0x7fffffff) | i1))
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return x*one;
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SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
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return x;
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} else { /* fraction part in low x */
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i = ((u_int32_t)(0x7fffffff))>>(jj0-32);
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if((i1&i)==0) { /* x is integral */
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*iptr = x;
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SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
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return x;
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} else {
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SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i));
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return x - *iptr;
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}
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}
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}
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