Chris@41: dnl @synopsis AC_C_CLIP_MODE
Chris@41: dnl
Chris@41: dnl Determine the clipping mode when converting float to int.
Chris@41: dnl @version 1.0	May 17 2003
Chris@41: dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
Chris@41: dnl
Chris@41: dnl Permission to use, copy, modify, distribute, and sell this file for any 
Chris@41: dnl purpose is hereby granted without fee, provided that the above copyright 
Chris@41: dnl and this permission notice appear in all copies.  No representations are
Chris@41: dnl made about the suitability of this software for any purpose.  It is 
Chris@41: dnl provided "as is" without express or implied warranty.
Chris@41: 
Chris@41: 
Chris@41: 
Chris@41: 
Chris@41: 
Chris@41: 
Chris@41: 
Chris@41: dnl Find the clipping mode in the following way:
Chris@41: dnl    1) If we are not cross compiling test it.
Chris@41: dnl    2) IF we are cross compiling, assume that clipping isn't done correctly.
Chris@41: 
Chris@41: AC_DEFUN([AC_C_CLIP_MODE],
Chris@41: [AC_CACHE_CHECK(processor clipping capabilities, 
Chris@41: 	ac_cv_c_clip_type,
Chris@41: 
Chris@41: # Initialize to unknown
Chris@41: ac_cv_c_clip_positive=unknown
Chris@41: ac_cv_c_clip_negative=unknown
Chris@41: 
Chris@41: 
Chris@41: if test $ac_cv_c_clip_positive = unknown ; then
Chris@41: 	AC_TRY_RUN(
Chris@41: 	[[
Chris@41: 	#define	_ISOC9X_SOURCE	1
Chris@41: 	#define _ISOC99_SOURCE	1
Chris@41: 	#define	__USE_ISOC99	1
Chris@41: 	#define __USE_ISOC9X	1
Chris@41: 	#include <math.h>
Chris@41: 	int main (void)
Chris@41: 	{	double	fval ;
Chris@41: 		int k, ival ;
Chris@41: 
Chris@41: 		fval = 1.0 * 0x7FFFFFFF ;
Chris@41: 		for (k = 0 ; k < 100 ; k++)
Chris@41: 		{	ival = (lrint (fval)) >> 24 ;
Chris@41: 			if (ival != 127)
Chris@41: 				return 1 ;
Chris@41: 		
Chris@41: 			fval *= 1.2499999 ;
Chris@41: 			} ;
Chris@41: 		
Chris@41: 			return 0 ;
Chris@41: 		}
Chris@41: 		]],
Chris@41: 		ac_cv_c_clip_positive=yes,
Chris@41: 		ac_cv_c_clip_positive=no,
Chris@41: 		ac_cv_c_clip_positive=unknown
Chris@41: 		)
Chris@41: 
Chris@41: 	AC_TRY_RUN(
Chris@41: 	[[
Chris@41: 	#define	_ISOC9X_SOURCE	1
Chris@41: 	#define _ISOC99_SOURCE	1
Chris@41: 	#define	__USE_ISOC99	1
Chris@41: 	#define __USE_ISOC9X	1
Chris@41: 	#include <math.h>
Chris@41: 	int main (void)
Chris@41: 	{	double	fval ;
Chris@41: 		int k, ival ;
Chris@41: 
Chris@41: 		fval = -8.0 * 0x10000000 ;
Chris@41: 		for (k = 0 ; k < 100 ; k++)
Chris@41: 		{	ival = (lrint (fval)) >> 24 ;
Chris@41: 			if (ival != -128)
Chris@41: 				return 1 ;
Chris@41: 		
Chris@41: 			fval *= 1.2499999 ;
Chris@41: 			} ;
Chris@41: 		
Chris@41: 			return 0 ;
Chris@41: 		}
Chris@41: 		]],
Chris@41: 		ac_cv_c_clip_negative=yes,
Chris@41: 		ac_cv_c_clip_negative=no,
Chris@41: 		ac_cv_c_clip_negative=unknown
Chris@41: 		)
Chris@41: 	fi
Chris@41: 
Chris@41: if test $ac_cv_c_clip_positive = yes ; then
Chris@41: 	ac_cv_c_clip_positive=1
Chris@41: else
Chris@41: 	ac_cv_c_clip_positive=0
Chris@41: 	fi
Chris@41: 
Chris@41: if test $ac_cv_c_clip_negative = yes ; then
Chris@41: 	ac_cv_c_clip_negative=1
Chris@41: else
Chris@41: 	ac_cv_c_clip_negative=0
Chris@41: 	fi
Chris@41: 
Chris@41: [[
Chris@41: case "$ac_cv_c_clip_positive$ac_cv_c_clip_negative" in
Chris@41: 	"00")
Chris@41: 		ac_cv_c_clip_type="none"
Chris@41: 		;;
Chris@41: 	"10")
Chris@41: 		ac_cv_c_clip_type="positive"
Chris@41: 		;;
Chris@41: 	"01")
Chris@41: 		ac_cv_c_clip_type="negative"
Chris@41: 		;;
Chris@41: 	"11")
Chris@41: 		ac_cv_c_clip_type="both"
Chris@41: 		;;
Chris@41: 	esac
Chris@41: 	]]
Chris@41: 
Chris@41: )
Chris@41: ]
Chris@41: 
Chris@41: )# AC_C_CLIP_MODE
Chris@41: 
Chris@41: