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131 lines
2.7 KiB
C
131 lines
2.7 KiB
C
/* Copyright 2016 Samsung Electronics Co., Ltd.
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* Copyright 2016 University of Szeged
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is based on work under the following copyright and permission
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* notice:
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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 SunSoft, 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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* @(#)s_floor.c 1.3 95/01/18
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*/
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#include "jerry-libm-internal.h"
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/* floor(x)
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* Return x rounded toward -inf to integral value
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*
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* Method:
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* Bit twiddling.
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*
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* Exception:
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* Inexact flag raised if x not equal to floor(x).
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*/
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#define huge 1.0e300
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double
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floor (double x)
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{
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int i0, i1, j0;
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unsigned i, j;
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i0 = __HI (x);
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i1 = __LO (x);
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j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
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if (j0 < 20)
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{
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if (j0 < 0) /* raise inexact if x != 0 */
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{
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if (huge + x > 0.0) /* return 0 * sign(x) if |x| < 1 */
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{
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if (i0 >= 0)
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{
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i0 = i1 = 0;
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}
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else if (((i0 & 0x7fffffff) | i1) != 0)
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{
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i0 = 0xbff00000;
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i1 = 0;
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}
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}
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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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return x;
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}
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if (huge + x > 0.0) /* raise inexact flag */
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{
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if (i0 < 0)
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{
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i0 += (0x00100000) >> j0;
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}
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i0 &= (~i);
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i1 = 0;
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}
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}
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}
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else if (j0 > 51)
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{
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if (j0 == 0x400) /* inf or NaN */
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{
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return x + x;
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}
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else /* x is integral */
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{
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return x;
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}
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}
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else
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{
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i = ((unsigned) (0xffffffff)) >> (j0 - 20);
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if ((i1 & i) == 0) /* x is integral */
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{
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return x;
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}
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if (huge + x > 0.0) /* raise inexact flag */
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{
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if (i0 < 0)
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{
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if (j0 == 20)
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{
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i0 += 1;
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}
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else
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{
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j = i1 + (1 << (52 - j0));
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if (j < i1) /* got a carry */
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{
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i0 += 1;
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}
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i1 = j;
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}
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}
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i1 &= (~i);
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}
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}
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__HI (x) = i0;
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__LO (x) = i1;
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return x;
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} /* floor */
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#undef huge
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