0cbb654791
zero, one, two, half are replaced by const literals The policy was to use the f suffix for float consts (1.0f), but don't use suffix for long double consts (these consts can be exactly represented as double).
68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
/* origin: FreeBSD /usr/src/lib/msun/src/s_modf.c */
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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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* 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 "libm.h"
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double modf(double x, double *iptr)
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{
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int32_t i0,i1,j0;
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uint32_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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if (j0 < 0) { /* |x| < 1 */
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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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i = 0x000fffff >> j0;
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if (((i0&i)|i1) == 0) { /* x is integral */
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uint32_t high;
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*iptr = x;
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GET_HIGH_WORD(high, x);
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INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
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return x;
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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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} else if (j0 > 51) { /* no fraction part */
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uint32_t high;
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if (j0 == 0x400) { /* inf/NaN */
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*iptr = x;
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return 0.0 / x;
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}
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*iptr = x;
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GET_HIGH_WORD(high, x);
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INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
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return x;
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} else { /* fraction part in low x */
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i = (uint32_t)0xffffffff >> (j0 - 20);
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if ((i1&i) == 0) { /* x is integral */
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uint32_t high;
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*iptr = x;
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GET_HIGH_WORD(high, x);
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INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
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return x;
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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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