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1 # ilogbf.m4 serial 1 |
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2 dnl Copyright (C) 2010-2015 Free Software Foundation, Inc. |
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3 dnl This file is free software; the Free Software Foundation |
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4 dnl gives unlimited permission to copy and/or distribute it, |
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5 dnl with or without modifications, as long as this notice is preserved. |
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6 |
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7 AC_DEFUN([gl_FUNC_ILOGBF], |
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8 [ |
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9 AC_REQUIRE([gl_MATH_H_DEFAULTS]) |
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10 |
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11 dnl Persuade glibc <math.h> to declare ilogbf(). |
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12 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) |
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13 |
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14 dnl Determine ILOGBF_LIBM. |
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15 gl_MATHFUNC([ilogbf], [int], [(float)]) |
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16 if test $gl_cv_func_ilogbf_no_libm = yes \ |
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17 || test $gl_cv_func_ilogbf_in_libm = yes; then |
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18 save_LIBS="$LIBS" |
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19 LIBS="$LIBS $ILOGBF_LIBM" |
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20 gl_FUNC_ILOGBF_WORKS |
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21 LIBS="$save_LIBS" |
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22 case "$gl_cv_func_ilogbf_works" in |
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23 *yes) ;; |
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24 *) REPLACE_ILOGBF=1 ;; |
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25 esac |
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26 else |
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27 HAVE_ILOGBF=0 |
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28 fi |
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29 if test $HAVE_ILOGBF = 0 || test $REPLACE_ILOGBF = 1; then |
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30 dnl Find libraries needed to link lib/ilogbf.c. |
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31 AC_REQUIRE([gl_FUNC_FREXPF]) |
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32 AC_REQUIRE([gl_FUNC_ISNANF]) |
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33 ILOGBF_LIBM= |
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34 dnl Append $FREXPF_LIBM to ILOGBF_LIBM, avoiding gratuitous duplicates. |
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35 case " $ILOGBF_LIBM " in |
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36 *" $FREXPF_LIBM "*) ;; |
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37 *) ILOGBF_LIBM="$ILOGBF_LIBM $FREXPF_LIBM" ;; |
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38 esac |
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39 dnl Append $ISNANF_LIBM to ILOGBF_LIBM, avoiding gratuitous duplicates. |
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40 case " $ILOGBF_LIBM " in |
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41 *" $ISNANF_LIBM "*) ;; |
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42 *) ILOGBF_LIBM="$ILOGBF_LIBM $ISNANF_LIBM" ;; |
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43 esac |
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44 fi |
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45 AC_SUBST([ILOGBF_LIBM]) |
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46 ]) |
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47 |
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48 dnl Test whether ilogbf() works. |
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49 dnl On OpenBSD 4.9, ilogbf(0.0) is wrong. |
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50 dnl On NetBSD 5.1, OpenBSD 4.9, ilogbf(Infinity) is wrong. |
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51 AC_DEFUN([gl_FUNC_ILOGBF_WORKS], |
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52 [ |
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53 AC_REQUIRE([AC_PROG_CC]) |
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54 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles |
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55 AC_CACHE_CHECK([whether ilogbf works], [gl_cv_func_ilogbf_works], |
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56 [ |
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57 AC_RUN_IFELSE( |
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58 [AC_LANG_SOURCE([[ |
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59 #include <limits.h> |
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60 #include <math.h> |
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61 /* Provide FP_ILOGB0, FP_ILOGBNAN, like in math.in.h. */ |
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62 #if !(defined FP_ILOGB0 && defined FP_ILOGBNAN) |
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63 # if defined __NetBSD__ || defined __sgi |
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64 /* NetBSD, IRIX 6.5: match what ilogbf() does */ |
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65 # define FP_ILOGB0 INT_MIN |
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66 # define FP_ILOGBNAN INT_MIN |
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67 # elif defined _AIX |
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68 /* AIX 5.1: match what ilogbf() does in AIX >= 5.2 */ |
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69 # define FP_ILOGB0 INT_MIN |
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70 # define FP_ILOGBNAN INT_MAX |
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71 # elif defined __sun |
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72 /* Solaris 9: match what ilogbf() does */ |
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73 # define FP_ILOGB0 (- INT_MAX) |
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74 # define FP_ILOGBNAN INT_MAX |
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75 # endif |
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76 #endif |
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77 volatile float x; |
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78 static float zero; |
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79 static int dummy (float x) { return 0; } |
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80 int main (int argc, char *argv[]) |
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81 { |
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82 int (*my_ilogbf) (float) = argc ? ilogbf : dummy; |
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83 int result = 0; |
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84 /* This test fails on OpenBSD 4.9. */ |
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85 { |
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86 x = 0.0f; |
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87 if (my_ilogbf (x) != FP_ILOGB0) |
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88 result |= 1; |
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89 } |
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90 /* This test fails on NetBSD 5.1, OpenBSD 4.9. */ |
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91 { |
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92 x = 1.0f / zero; |
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93 if (my_ilogbf (x) != INT_MAX) |
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94 result |= 2; |
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95 } |
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96 return result; |
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97 } |
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98 ]])], |
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99 [gl_cv_func_ilogbf_works=yes], |
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100 [gl_cv_func_ilogbf_works=no], |
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101 [case "$host_os" in |
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102 openbsd* | netbsd*) gl_cv_func_ilogbf_works="guessing no";; |
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103 *) gl_cv_func_ilogbf_works="guessing yes";; |
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104 esac |
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105 ]) |
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106 ]) |
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107 ]) |
