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85 lines
2.5 KiB
C
85 lines
2.5 KiB
C
/* lround adapted to be llround for Newlib, 2009 by Craig Howland. */
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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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#ifndef _DOUBLE_IS_32BITS
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long long int
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llround(double x)
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{
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__int32_t sign, exponent_less_1023;
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/* Most significant word, least significant word. */
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__uint32_t msw, lsw;
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long long int result;
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EXTRACT_WORDS(msw, lsw, x);
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/* Extract sign. */
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sign = ((msw & 0x80000000) ? -1 : 1);
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/* Extract exponent field. */
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exponent_less_1023 = ((msw & 0x7ff00000) >> 20) - 1023;
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msw &= 0x000fffff;
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msw |= 0x00100000;
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/* exponent_less_1023 in [-1023,1024] */
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if (exponent_less_1023 < 20)
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{
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/* exponent_less_1023 in [-1023,19] */
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if (exponent_less_1023 < 0)
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{
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if (exponent_less_1023 < -1)
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return 0;
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else
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return sign;
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}
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else
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{
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/* exponent_less_1023 in [0,19] */
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/* shift amt in [0,19] */
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msw += 0x80000 >> exponent_less_1023;
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/* shift amt in [20,1] */
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result = msw >> (20 - exponent_less_1023);
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}
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}
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else if (exponent_less_1023 < (8 * sizeof (long long int)) - 1)
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{
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/* 64bit longlong: exponent_less_1023 in [20,62] */
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if (exponent_less_1023 >= 52)
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/* 64bit longlong: exponent_less_1023 in [52,62] */
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/* 64bit longlong: shift amt in [32,42] */
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result = ((long long int) msw << (exponent_less_1023 - 20))
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/* 64bit longlong: shift amt in [0,10] */
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| (lsw << (exponent_less_1023 - 52));
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else
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{
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/* 64bit longlong: exponent_less_1023 in [20,51] */
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unsigned int tmp = lsw
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/* 64bit longlong: shift amt in [0,31] */
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+ (0x80000000 >> (exponent_less_1023 - 20));
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if (tmp < lsw)
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++msw;
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/* 64bit longlong: shift amt in [0,31] */
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result = ((long long int) msw << (exponent_less_1023 - 20))
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/* ***64bit longlong: shift amt in [32,1] */
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| SAFE_RIGHT_SHIFT (tmp, (52 - exponent_less_1023));
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}
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}
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else
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/* Result is too large to be represented by a long long int. */
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return (long long int)x;
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return sign * result;
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}
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#endif /* _DOUBLE_IS_32BITS */
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