cannam@125: dnl @synopsis MN_C_CLIP_MODE
cannam@125: dnl
cannam@125: dnl Determine the clipping mode when converting float to int.
cannam@125: dnl @version 1.0	May 17 2003
cannam@125: dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
cannam@125: dnl
cannam@125: dnl Permission to use, copy, modify, distribute, and sell this file for any 
cannam@125: dnl purpose is hereby granted without fee, provided that the above copyright 
cannam@125: dnl and this permission notice appear in all copies.  No representations are
cannam@125: dnl made about the suitability of this software for any purpose.  It is 
cannam@125: dnl provided "as is" without express or implied warranty.
cannam@125: 
cannam@125: 
cannam@125: 
cannam@125: 
cannam@125: 
cannam@125: 
cannam@125: 
cannam@125: dnl Find the clipping mode in the following way:
cannam@125: dnl    1) If we are not cross compiling test it.
cannam@125: dnl    2) IF we are cross compiling, assume that clipping isn't done correctly.
cannam@125: 
cannam@125: AC_DEFUN([MN_C_CLIP_MODE],
cannam@125: [AC_CACHE_CHECK(processor clipping capabilities, 
cannam@125: 	ac_cv_c_clip_type,
cannam@125: 
cannam@125: # Initialize to unknown
cannam@125: ac_cv_c_clip_positive=unknown
cannam@125: ac_cv_c_clip_negative=unknown
cannam@125: 
cannam@125: 
cannam@125: if test $ac_cv_c_clip_positive = unknown ; then
cannam@125: 	AC_TRY_RUN(
cannam@125: 	[[
cannam@125: 	#define	_ISOC9X_SOURCE	1
cannam@125: 	#define _ISOC99_SOURCE	1
cannam@125: 	#define	__USE_ISOC99	1
cannam@125: 	#define __USE_ISOC9X	1
cannam@125: 	#include <math.h>
cannam@125: 	int main (void)
cannam@125: 	{	double	fval ;
cannam@125: 		int k, ival ;
cannam@125: 
cannam@125: 		fval = 1.0 * 0x7FFFFFFF ;
cannam@125: 		for (k = 0 ; k < 100 ; k++)
cannam@125: 		{	ival = (lrint (fval)) >> 24 ;
cannam@125: 			if (ival != 127)
cannam@125: 				return 1 ;
cannam@125: 		
cannam@125: 			fval *= 1.2499999 ;
cannam@125: 			} ;
cannam@125: 		
cannam@125: 			return 0 ;
cannam@125: 		}
cannam@125: 		]],
cannam@125: 		ac_cv_c_clip_positive=yes,
cannam@125: 		ac_cv_c_clip_positive=no,
cannam@125: 		ac_cv_c_clip_positive=unknown
cannam@125: 		)
cannam@125: 
cannam@125: 	AC_TRY_RUN(
cannam@125: 	[[
cannam@125: 	#define	_ISOC9X_SOURCE	1
cannam@125: 	#define _ISOC99_SOURCE	1
cannam@125: 	#define	__USE_ISOC99	1
cannam@125: 	#define __USE_ISOC9X	1
cannam@125: 	#include <math.h>
cannam@125: 	int main (void)
cannam@125: 	{	double	fval ;
cannam@125: 		int k, ival ;
cannam@125: 
cannam@125: 		fval = -8.0 * 0x10000000 ;
cannam@125: 		for (k = 0 ; k < 100 ; k++)
cannam@125: 		{	ival = (lrint (fval)) >> 24 ;
cannam@125: 			if (ival != -128)
cannam@125: 				return 1 ;
cannam@125: 		
cannam@125: 			fval *= 1.2499999 ;
cannam@125: 			} ;
cannam@125: 		
cannam@125: 			return 0 ;
cannam@125: 		}
cannam@125: 		]],
cannam@125: 		ac_cv_c_clip_negative=yes,
cannam@125: 		ac_cv_c_clip_negative=no,
cannam@125: 		ac_cv_c_clip_negative=unknown
cannam@125: 		)
cannam@125: 	fi
cannam@125: 
cannam@125: if test $ac_cv_c_clip_positive = yes ; then
cannam@125: 	ac_cv_c_clip_positive=1
cannam@125: else
cannam@125: 	ac_cv_c_clip_positive=0
cannam@125: 	fi
cannam@125: 
cannam@125: if test $ac_cv_c_clip_negative = yes ; then
cannam@125: 	ac_cv_c_clip_negative=1
cannam@125: else
cannam@125: 	ac_cv_c_clip_negative=0
cannam@125: 	fi
cannam@125: 
cannam@125: [[
cannam@125: case "$ac_cv_c_clip_positive$ac_cv_c_clip_negative" in
cannam@125: 	"00")
cannam@125: 		ac_cv_c_clip_type="none"
cannam@125: 		;;
cannam@125: 	"10")
cannam@125: 		ac_cv_c_clip_type="positive"
cannam@125: 		;;
cannam@125: 	"01")
cannam@125: 		ac_cv_c_clip_type="negative"
cannam@125: 		;;
cannam@125: 	"11")
cannam@125: 		ac_cv_c_clip_type="both"
cannam@125: 		;;
cannam@125: 	esac
cannam@125: 	]]
cannam@125: 
cannam@125: )
cannam@125: ]
cannam@125: 
cannam@125: )# MN_C_CLIP_MODE
cannam@125: 
cannam@125: