83 lines
1.5 KiB
C
83 lines
1.5 KiB
C
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// Emacs style mode select -*- C++ -*-
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//-----------------------------------------------------------------------------
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//
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// $Id:$
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//
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// Copyright (C) 1993-1996 by id Software, Inc.
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your option) any later version.
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//
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// This program 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
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// GNU General Public License for more details.
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//
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// $Log:$
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//
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// DESCRIPTION:
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// Fixed point implementation.
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//
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//-----------------------------------------------------------------------------
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#include "stdlib.h"
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#include "doomtype.h"
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#include "i_system.h"
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#include "m_fixed.h"
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// Fixme. __USE_C_FIXED__ or something.
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fixed_t
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FixedMul
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( fixed_t a,
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fixed_t b )
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{
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return ((long long) a * (long long) b) >> FRACBITS;
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}
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//
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// FixedDiv, C version.
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//
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fixed_t
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FixedDiv
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( fixed_t a,
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fixed_t b )
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{
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if ( (abs(a)>>14) >= abs(b))
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return (a^b)<0 ? MININT : MAXINT;
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return FixedDiv2 (a,b);
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}
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fixed_t
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FixedDiv2
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( fixed_t a,
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fixed_t b )
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{
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#if 1
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long long c;
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c = ((long long)a<<16) / ((long long)b);
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return (fixed_t) c;
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#else
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double c;
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c = ((double)a) / ((double)b) * FRACUNIT;
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if (c >= 2147483648.0 || c < -2147483648.0)
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I_Error("FixedDiv: divide by zero");
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return (fixed_t) c;
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#endif
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}
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