annotate src/rubberband-1.8.1/src/float_cast/float_cast.h @ 164:9fa11135915a

This Mac compatibility fix appears to work, resolving SourceForge issue #273 Port Audio Fail on MacOS Catalina (10.15) - merging back

#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 (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