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78 lines
2.1 KiB
C
78 lines
2.1 KiB
C
/* Math functions for i387.
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Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by John C. Bowman <bowman@ipp-garching.mpg.de>, 1995.
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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, write to the Free
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Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA.
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*/
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#include <win32k.h>
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INT
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APIENTRY
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EngMulDiv(
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_In_ INT iMultiplicand,
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_In_ INT iMultiplier,
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_In_ INT iDivisor)
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{
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INT64 i64Multiplied, i64Result;
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/* Check for divide by zero */
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if (iDivisor == 0)
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{
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/* Quick sign check and return "infinite" */
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return ((iMultiplicand ^ iMultiplier) < 0) ? INT_MIN : INT_MAX;
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}
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/* We want to deal with a positive divisor to simplify the logic. */
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if (iDivisor < 0)
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{
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iMultiplicand = -iMultiplicand;
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iDivisor = -iDivisor;
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}
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/* Do the multiplication */
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i64Multiplied = Int32x32To64(iMultiplicand, iMultiplier);
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/* If the result is positive, we add to round, else we subtract to round. */
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if (i64Multiplied >= 0)
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{
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i64Multiplied += (iDivisor / 2);
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}
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else
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{
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i64Multiplied -= (iDivisor / 2);
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}
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/* Now do the divide */
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i64Result = i64Multiplied / iDivisor;
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/* Check for positive overflow */
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if (i64Result > INT_MAX)
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{
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return INT_MAX;
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}
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/* Check for negative overflow. */
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if (i64Result < INT_MIN)
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{
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return INT_MIN;
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}
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return (INT)i64Result;
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}
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