Reorganise into faster (R2) and finer (R3)

src/ext/float_cast/float_cast.h

@@ -0,0 +1,81 @@
+#ifndef ERIKD_FLOATCAST_H
+#define ERIKD_FLOATCAST_H
+
+/*
+** Copyright (C) 2001 Erik de Castro Lopo <erikd AT mega-nerd DOT com>
+**
+** Permission to use, copy, modify, distribute, and sell this file for any 
+** purpose is hereby granted without fee, provided that the above copyright 
+** and this permission notice appear in all copies.  No representations are
+** made about the suitability of this software for any purpose.  It is 
+** provided "as is" without express or implied warranty.
+*/
+
+/* Version 1.1 */
+
+
+/*============================================================================ 
+**	On Intel Pentium processors (especially PIII and probably P4), converting
+**	from float to int is very slow. To meet the C specs, the code produced by 
+**	most C compilers targeting Pentium needs to change the FPU rounding mode 
+**	before the float to int conversion is performed. 
+**
+**	Changing the FPU rounding mode causes the FPU pipeline to be flushed. It 
+**	is this flushing of the pipeline which is so slow.
+**
+**	Fortunately the ISO C99 specifications define the functions lrint, lrintf,
+**	llrint and llrintf which fix this problem as a side effect. 
+**
+**	On Unix-like systems, the configure process should have detected the 
+**	presence of these functions. If they weren't found we have to replace them 
+**	here with a standard C cast.
+*/
+
+/*	
+**	The C99 prototypes for lrint and lrintf are as follows:
+**	
+**		long int lrintf (float x) ;
+**		long int lrint  (double x) ;
+*/
+
+#if (defined (_WIN64))
+
+#include <math.h>
+__inline long int lrint(double flt) { return (long int)flt; }
+__inline long int lrintf(float flt) { return (long int)flt; }
+
+#elif (defined (WIN32) || defined (_WIN32))
+
+	#include	<math.h>
+
+	/*	Win32 doesn't seem to have these functions. 
+	**	Therefore implement inline versions of these functions here.
+	*/
+	
+	__inline long int 
+	lrint (double flt) 
+	{	int intgr;
+
+		_asm
+		{	fld flt
+			fistp intgr
+			} ;
+			
+		return intgr ;
+	} 
+	
+	__inline long int 
+	lrintf (float flt)
+	{	int intgr;
+
+		_asm
+		{	fld flt
+			fistp intgr
+			} ;
+			
+		return intgr ;
+	}
+
+#endif
+
+#endif