1 files changed, 101 insertions, 0 deletions

diff --git a/src/m_fixed.h b/src/m_fixed.h
new file mode 100644
index 0000000..2eb36db
--- /dev/null
+++ b/src/m_fixed.h
@@ -0,0 +1,101 @@
+/* Emacs style mode select   -*- C++ -*-
+ *-----------------------------------------------------------------------------
+ *
+ *
+ *  PrBoom: a Doom port merged with LxDoom and LSDLDoom
+ *  based on BOOM, a modified and improved DOOM engine
+ *  Copyright (C) 1999 by
+ *  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
+ *  Copyright (C) 1999-2000 by
+ *  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
+ *  Copyright 2005, 2006 by
+ *  Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ *  02111-1307, USA.
+ *
+ * DESCRIPTION:
+ *      Fixed point arithemtics, implementation.
+ *
+ *-----------------------------------------------------------------------------*/
+
+#ifndef __M_FIXED__
+#define __M_FIXED__
+
+#include "config.h"
+#include "doomtype.h"
+
+/*
+ * Fixed point, 32bit as 16.16.
+ */
+
+#define FRACBITS 16
+#define FRACUNIT (1<<FRACBITS)
+
+typedef int fixed_t;
+
+/*
+ * Absolute Value
+ *
+ * killough 5/10/98: In djgpp, use inlined assembly for performance
+ * killough 9/05/98: better code seems to be gotten from using inlined C
+ */
+
+inline static const int D_abs(int x)
+{
+  fixed_t _t = (x),_s;
+  _s = _t >> (8*sizeof _t-1);
+  return (_t^_s)-_s;
+}
+/*
+ * Fixed Point Multiplication
+ */
+
+/* CPhipps - made __inline__ to inline, as specified in the gcc docs
+ * Also made const */
+
+inline static CONSTFUNC fixed_t FixedMul(fixed_t a, fixed_t b)
+{
+  return (fixed_t)((int_64_t) a*b >> FRACBITS);
+}
+/*
+ * Fixed Point Division
+ */
+
+/* CPhipps - made __inline__ to inline, as specified in the gcc docs
+ * Also made const */
+
+inline static CONSTFUNC fixed_t FixedDiv(fixed_t a, fixed_t b)
+{
+  return ((unsigned)D_abs(a)>>14) >= (unsigned)D_abs(b) ? ((a^b)>>31) ^ INT_MAX :
+    (fixed_t)(((int_64_t) a << FRACBITS) / b);
+}
+
+
+/* CPhipps -
+ * FixedMod - returns a % b, guaranteeing 0<=a<b
+ * (notice that the C standard for % does not guarantee this)
+ */
+
+inline static CONSTFUNC fixed_t FixedMod(fixed_t a, fixed_t b)
+{
+  if (b & (b-1)) {
+    fixed_t r = a % b;
+    return ((r<0) ? r+b : r);
+  } else
+    return (a & (b-1));
+}
+
+#endif