[AD] fixmul bis

[Evert Glebbeek <eglebbk@xxxxxxxxxx>]

Attached is another modified version of Peter's patch to the one I posted 
in my other message that hasn't arrived yet.
It uses LONG_LONG to do 64 bit arithmetic when it is available. Tested 
locally (but not benchmarked yet).

Evert

? allegro.vcproj
Index: include/allegro/inline/fmaths.inl
===================================================================
RCS file: /cvsroot/alleg/allegro/include/allegro/inline/fmaths.inl,v
retrieving revision 1.7
diff -u -r1.7 fmaths.inl
--- include/allegro/inline/fmaths.inl	1 Feb 2005 13:12:04 -0000	1.7
+++ include/allegro/inline/fmaths.inl	16 May 2005 08:29:28 -0000
@@ -103,7 +103,30 @@
 
 AL_INLINE(fixed, fixmul, (fixed x, fixed y),
 {
+#if 0
    return ftofix(fixtof(x) * fixtof(y));
+#elif defined LONG_LONG
+   LONG_LONG lx = x;
+   LONG_LONG ly = y;
+   LONG_LONG lres = (lx*ly)>>16;
+   int res = lres;
+   return res;
+#else
+   fixed sign = (x^y) & 0x80000000;
+   int mask_x = x >> 31;
+   int mask_y = y >> 31;
+   int mask_result = sign >> 31;
+   fixed result;
+
+   x = (x^mask_x) - mask_x;
+   y = (y^mask_y) - mask_y;
+
+   result = ((y >> 8)*(x >> 8) +
+             (((y >> 8)*(x&0xff)) >> 8) +
+             (((x >> 8)*(y&0xff)) >> 8));
+
+   return (result^mask_result) - mask_result;
+#endif
 })