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57 lines
1.7 KiB
C
57 lines
1.7 KiB
C
/* Software floating-point emulation.
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Helper routine for _q_* routines.
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Simulate exceptions using double arithmetics.
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Copyright (C) 1999, 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Jakub Jelinek (jj@ultra.linux.cz).
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include "soft-fp.h"
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unsigned long long ___q_numbers [] = {
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0x0000000000000000ULL, /* Zero */
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0x0010100000000000ULL, /* Very tiny number */
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0x0010000000000000ULL, /* Minimum normalized number */
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0x7fef000000000000ULL, /* A huge double number */
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};
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double ___q_simulate_exceptions(int exceptions)
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{
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double d, *p = (double *)___q_numbers;
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if (exceptions & FP_EX_INVALID)
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d = p[0]/p[0];
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if (exceptions & FP_EX_OVERFLOW)
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{
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d = p[3] + p[3];
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exceptions &= ~FP_EX_INEXACT;
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}
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if (exceptions & FP_EX_UNDERFLOW)
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{
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if (exceptions & FP_EX_INEXACT)
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{
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d = p[2] * p[2];
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exceptions &= ~FP_EX_INEXACT;
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}
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else
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d = p[1] - p[2];
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}
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if (exceptions & FP_EX_DIVZERO)
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d = 1.0/p[0];
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if (exceptions & FP_EX_INEXACT)
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d = p[3] - p[2];
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return d;
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}
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