[audio-libsamplerate.git] / libsamplerate / M4 / clip_mode.m4

dnl @synopsis AC_C_CLIP_MODE
dnl
dnl Determine the clipping mode when converting float to int.
dnl @version 1.0	May 17 2003
dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
dnl
dnl Permission to use, copy, modify, distribute, and sell this file for any 
dnl purpose is hereby granted without fee, provided that the above copyright 
dnl and this permission notice appear in all copies.  No representations are
dnl made about the suitability of this software for any purpose.  It is 
dnl provided "as is" without express or implied warranty.


dnl Find the clipping mode in the following way:
dnl    1) If we are not cross compiling test it.
dnl    2) IF we are cross compiling, assume that clipping isn't done correctly.

AC_DEFUN([AC_C_CLIP_MODE],
[AC_CACHE_CHECK(processor clipping capabilities, 
	ac_cv_c_clip_type,

# Initialize to unknown
ac_cv_c_clip_positive=unknown
ac_cv_c_clip_negative=unknown


if test $ac_cv_c_clip_positive = unknown ; then
	AC_TRY_RUN(
	[[
	#define	_ISOC9X_SOURCE	1
	#define _ISOC99_SOURCE	1
	#define	__USE_ISOC99	1
	#define __USE_ISOC9X	1
	#include <math.h>
	int main (void)
	{	double	fval ;
		int k, ival ;

		fval = 1.0 * 0x7FFFFFFF ;
		for (k = 0 ; k < 100 ; k++)
		{	ival = (lrint (fval)) >> 24 ;
			if (ival != 127)
				return 1 ;
		
			fval *= 1.2499999 ;
			} ;
		
			return 0 ;
		}
		]],
		ac_cv_c_clip_positive=yes,
		ac_cv_c_clip_positive=no,
		ac_cv_c_clip_positive=unknown
		)

	AC_TRY_RUN(
	[[
	#define	_ISOC9X_SOURCE	1
	#define _ISOC99_SOURCE	1
	#define	__USE_ISOC99	1
	#define __USE_ISOC9X	1
	#include <math.h>
	int main (void)
	{	double	fval ;
		int k, ival ;

		fval = -8.0 * 0x10000000 ;
		for (k = 0 ; k < 100 ; k++)
		{	ival = (lrint (fval)) >> 24 ;
			if (ival != -128)
				return 1 ;
		
			fval *= 1.2499999 ;
			} ;
		
			return 0 ;
		}
		]],
		ac_cv_c_clip_negative=yes,
		ac_cv_c_clip_negative=no,
		ac_cv_c_clip_negative=unknown
		)
	fi

if test $ac_cv_c_clip_positive = yes ; then
	ac_cv_c_clip_positive=1
else
	ac_cv_c_clip_positive=0
	fi

if test $ac_cv_c_clip_negative = yes ; then
	ac_cv_c_clip_negative=1
else
	ac_cv_c_clip_negative=0
	fi

[[
case "$ac_cv_c_clip_positive$ac_cv_c_clip_negative" in
	"00")
		ac_cv_c_clip_type="none"
		;;
	"10")
		ac_cv_c_clip_type="positive"
		;;
	"01")
		ac_cv_c_clip_type="negative"
		;;
	"11")
		ac_cv_c_clip_type="both"
		;;
	esac
	]]

)
]

)# AC_C_CLIP_MODE
Commit	Line	Data
8529da43 MG	1	dnl @synopsis AC_C_CLIP_MODE
	2	dnl
	3	dnl Determine the clipping mode when converting float to int.
	4	dnl @version 1.0 May 17 2003
	5	dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
	6	dnl
	7	dnl Permission to use, copy, modify, distribute, and sell this file for any
	8	dnl purpose is hereby granted without fee, provided that the above copyright
	9	dnl and this permission notice appear in all copies. No representations are
	10	dnl made about the suitability of this software for any purpose. It is
	11	dnl provided "as is" without express or implied warranty.
	12
	13
	14
	15
	16
	17
	18
	19	dnl Find the clipping mode in the following way:
	20	dnl 1) If we are not cross compiling test it.
	21	dnl 2) IF we are cross compiling, assume that clipping isn't done correctly.
	22
	23	AC_DEFUN([AC_C_CLIP_MODE],
	24	[AC_CACHE_CHECK(processor clipping capabilities,
	25	ac_cv_c_clip_type,
	26
	27	# Initialize to unknown
	28	ac_cv_c_clip_positive=unknown
	29	ac_cv_c_clip_negative=unknown
	30
	31
	32	if test $ac_cv_c_clip_positive = unknown ; then
	33	AC_TRY_RUN(
	34	[[
	35	#define _ISOC9X_SOURCE 1
	36	#define _ISOC99_SOURCE 1
	37	#define __USE_ISOC99 1
	38	#define __USE_ISOC9X 1
	39	#include <math.h>
	40	int main (void)
	41	{ double fval ;
	42	int k, ival ;
	43
	44	fval = 1.0 * 0x7FFFFFFF ;
	45	for (k = 0 ; k < 100 ; k++)
	46	{ ival = (lrint (fval)) >> 24 ;
	47	if (ival != 127)
	48	return 1 ;
	49
	50	fval *= 1.2499999 ;
	51	} ;
	52
	53	return 0 ;
	54	}
	55	]],
	56	ac_cv_c_clip_positive=yes,
	57	ac_cv_c_clip_positive=no,
	58	ac_cv_c_clip_positive=unknown
	59	)
	60
	61	AC_TRY_RUN(
	62	[[
	63	#define _ISOC9X_SOURCE 1
	64	#define _ISOC99_SOURCE 1
65	#define __USE_ISOC99 1
66	#define __USE_ISOC9X 1
67	#include <math.h>
68	int main (void)
69	{ double fval ;
70	int k, ival ;
71
72	fval = -8.0 * 0x10000000 ;
73	for (k = 0 ; k < 100 ; k++)
74	{ ival = (lrint (fval)) >> 24 ;
75	if (ival != -128)
76	return 1 ;
77
78	fval *= 1.2499999 ;
79	} ;
80
81	return 0 ;
82	}
83	]],
84	ac_cv_c_clip_negative=yes,
85	ac_cv_c_clip_negative=no,
86	ac_cv_c_clip_negative=unknown
87	)
88	fi
89
90	if test $ac_cv_c_clip_positive = yes ; then
91	ac_cv_c_clip_positive=1
92	else
93	ac_cv_c_clip_positive=0
94	fi
95
96	if test $ac_cv_c_clip_negative = yes ; then
97	ac_cv_c_clip_negative=1
98	else
99	ac_cv_c_clip_negative=0
100	fi
101
102	[[
103	case "$ac_cv_c_clip_positive$ac_cv_c_clip_negative" in
104	"00")
105	ac_cv_c_clip_type="none"
106	;;
107	"10")
108	ac_cv_c_clip_type="positive"
109	;;
110	"01")
111	ac_cv_c_clip_type="negative"
112	;;
113	"11")
114	ac_cv_c_clip_type="both"
115	;;
116	esac
117	]]
118
119	)
120	]
121
122	)# AC_C_CLIP_MODE
123
124