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