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87 lines
2.1 KiB
C
87 lines
2.1 KiB
C
/*
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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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* modf(double x, 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 <math.h>
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#include <math_private.h>
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static const double one = 1.0;
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double
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__modf (double x, double *iptr)
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{
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int32_t i0, i1, j0;
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u_int32_t i;
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EXTRACT_WORDS (i0, i1, x);
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j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; /* exponent of x */
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if (j0 < 20) /* integer part in high x */
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{
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if (j0 < 0) /* |x|<1 */
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{
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INSERT_WORDS (*iptr, i0 & 0x80000000, 0); /* *iptr = +-0 */
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return x;
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}
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else
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{
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i = (0x000fffff) >> j0;
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if (((i0 & i) | i1) == 0) /* x is integral */
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{
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*iptr = x;
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INSERT_WORDS (x, i0 & 0x80000000, 0); /* return +-0 */
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return x;
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}
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else
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{
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INSERT_WORDS (*iptr, i0 & (~i), 0);
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return x - *iptr;
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}
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}
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}
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else if (__builtin_expect (j0 > 51, 0)) /* no fraction part */
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{
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*iptr = x * one;
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/* We must handle NaNs separately. */
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if (j0 == 0x400 && ((i0 & 0xfffff) | i1))
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return x * one;
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INSERT_WORDS (x, i0 & 0x80000000, 0); /* return +-0 */
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return x;
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}
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else /* fraction part in low x */
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{
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i = ((u_int32_t) (0xffffffff)) >> (j0 - 20);
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if ((i1 & i) == 0) /* x is integral */
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{
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*iptr = x;
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INSERT_WORDS (x, i0 & 0x80000000, 0); /* return +-0 */
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return x;
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}
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else
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{
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INSERT_WORDS (*iptr, 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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weak_alias (__modf, modf)
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#ifdef NO_LONG_DOUBLE
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strong_alias (__modf, __modfl)
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weak_alias (__modf, modfl)
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#endif
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