cannam@126: dnl @synopsis AC_C_CLIP_MODE
cannam@126: dnl
cannam@126: dnl Determine the clipping mode when converting float to int.
cannam@126: dnl @version 1.0	May 17 2003
cannam@126: dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
cannam@126: dnl
cannam@126: dnl Permission to use, copy, modify, distribute, and sell this file for any 
cannam@126: dnl purpose is hereby granted without fee, provided that the above copyright 
cannam@126: dnl and this permission notice appear in all copies.  No representations are
cannam@126: dnl made about the suitability of this software for any purpose.  It is 
cannam@126: dnl provided "as is" without express or implied warranty.
cannam@126: 
cannam@126: 
cannam@126: 
cannam@126: 
cannam@126: 
cannam@126: 
cannam@126: 
cannam@126: dnl Find the clipping mode in the following way:
cannam@126: dnl    1) If we are not cross compiling test it.
cannam@126: dnl    2) IF we are cross compiling, assume that clipping isn't done correctly.
cannam@126: 
cannam@126: AC_DEFUN([AC_C_CLIP_MODE],
cannam@126: [AC_CACHE_CHECK(processor clipping capabilities, 
cannam@126: 	ac_cv_c_clip_type,
cannam@126: 
cannam@126: # Initialize to unknown
cannam@126: ac_cv_c_clip_positive=unknown
cannam@126: ac_cv_c_clip_negative=unknown
cannam@126: 
cannam@126: 
cannam@126: if test $ac_cv_c_clip_positive = unknown ; then
cannam@126: 	AC_TRY_RUN(
cannam@126: 	[[
cannam@126: 	#define	_ISOC9X_SOURCE	1
cannam@126: 	#define _ISOC99_SOURCE	1
cannam@126: 	#define	__USE_ISOC99	1
cannam@126: 	#define __USE_ISOC9X	1
cannam@126: 	#include <math.h>
cannam@126: 	int main (void)
cannam@126: 	{	double	fval ;
cannam@126: 		int k, ival ;
cannam@126: 
cannam@126: 		fval = 1.0 * 0x7FFFFFFF ;
cannam@126: 		for (k = 0 ; k < 100 ; k++)
cannam@126: 		{	ival = (lrint (fval)) >> 24 ;
cannam@126: 			if (ival != 127)
cannam@126: 				return 1 ;
cannam@126: 		
cannam@126: 			fval *= 1.2499999 ;
cannam@126: 			} ;
cannam@126: 		
cannam@126: 			return 0 ;
cannam@126: 		}
cannam@126: 		]],
cannam@126: 		ac_cv_c_clip_positive=yes,
cannam@126: 		ac_cv_c_clip_positive=no,
cannam@126: 		ac_cv_c_clip_positive=unknown
cannam@126: 		)
cannam@126: 
cannam@126: 	AC_TRY_RUN(
cannam@126: 	[[
cannam@126: 	#define	_ISOC9X_SOURCE	1
cannam@126: 	#define _ISOC99_SOURCE	1
cannam@126: 	#define	__USE_ISOC99	1
cannam@126: 	#define __USE_ISOC9X	1
cannam@126: 	#include <math.h>
cannam@126: 	int main (void)
cannam@126: 	{	double	fval ;
cannam@126: 		int k, ival ;
cannam@126: 
cannam@126: 		fval = -8.0 * 0x10000000 ;
cannam@126: 		for (k = 0 ; k < 100 ; k++)
cannam@126: 		{	ival = (lrint (fval)) >> 24 ;
cannam@126: 			if (ival != -128)
cannam@126: 				return 1 ;
cannam@126: 		
cannam@126: 			fval *= 1.2499999 ;
cannam@126: 			} ;
cannam@126: 		
cannam@126: 			return 0 ;
cannam@126: 		}
cannam@126: 		]],
cannam@126: 		ac_cv_c_clip_negative=yes,
cannam@126: 		ac_cv_c_clip_negative=no,
cannam@126: 		ac_cv_c_clip_negative=unknown
cannam@126: 		)
cannam@126: 	fi
cannam@126: 
cannam@126: if test $ac_cv_c_clip_positive = yes ; then
cannam@126: 	ac_cv_c_clip_positive=1
cannam@126: else
cannam@126: 	ac_cv_c_clip_positive=0
cannam@126: 	fi
cannam@126: 
cannam@126: if test $ac_cv_c_clip_negative = yes ; then
cannam@126: 	ac_cv_c_clip_negative=1
cannam@126: else
cannam@126: 	ac_cv_c_clip_negative=0
cannam@126: 	fi
cannam@126: 
cannam@126: [[
cannam@126: case "$ac_cv_c_clip_positive$ac_cv_c_clip_negative" in
cannam@126: 	"00")
cannam@126: 		ac_cv_c_clip_type="none"
cannam@126: 		;;
cannam@126: 	"10")
cannam@126: 		ac_cv_c_clip_type="positive"
cannam@126: 		;;
cannam@126: 	"01")
cannam@126: 		ac_cv_c_clip_type="negative"
cannam@126: 		;;
cannam@126: 	"11")
cannam@126: 		ac_cv_c_clip_type="both"
cannam@126: 		;;
cannam@126: 	esac
cannam@126: 	]]
cannam@126: 
cannam@126: )
cannam@126: ]
cannam@126: 
cannam@126: )# AC_C_CLIP_MODE
cannam@126: 
cannam@126: