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1 //================================================================= |
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2 // |
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3 // rand4.c |
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4 // |
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5 // Testcase for C library rand() |
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6 // |
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7 //================================================================= |
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8 //####COPYRIGHTBEGIN#### |
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9 // |
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10 // ------------------------------------------- |
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11 // The contents of this file are subject to the Cygnus eCos Public License |
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12 // Version 1.0 (the "License"); you may not use this file except in |
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13 // compliance with the License. You may obtain a copy of the License at |
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14 // http://sourceware.cygnus.com/ecos |
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15 // |
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16 // Software distributed under the License is distributed on an "AS IS" |
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17 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the |
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18 // License for the specific language governing rights and limitations under |
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19 // the License. |
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20 // |
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21 // The Original Code is eCos - Embedded Cygnus Operating System, released |
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22 // September 30, 1998. |
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23 // |
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24 // The Initial Developer of the Original Code is Cygnus. Portions created |
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25 // by Cygnus are Copyright (C) 1998,1999 Cygnus Solutions. All Rights Reserved. |
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26 // ------------------------------------------- |
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27 // |
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28 //####COPYRIGHTEND#### |
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29 //================================================================= |
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30 //#####DESCRIPTIONBEGIN#### |
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31 // |
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32 // Author(s): rosalia |
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33 // Contributors: rosalia, jlarmour |
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34 // Date: 1999-03-19 |
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35 // Description: Contains testcode for C library rand() function. This tests |
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36 // that random numbers do not have periodicity in the lower |
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37 // bit |
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38 // |
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39 // |
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40 //####DESCRIPTIONEND#### |
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41 |
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42 // CONFIGURATION |
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43 |
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44 #include <pkgconf/libc.h> // C library configuration |
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45 |
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46 // INCLUDES |
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47 |
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48 #include <stdlib.h> |
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49 #include <cyg/infra/testcase.h> |
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50 #include <sys/cstartup.h> // C library initialisation |
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51 |
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52 // CONSTANTS |
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53 |
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54 #define TEST_LENGTH 100000 // how many samples to take |
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55 |
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56 // DEFINES |
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57 |
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58 #define TEST_VALID (!defined(CYGIMP_LIBC_RAND_SIMPLEST)) |
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59 |
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60 // FUNCTIONS |
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61 |
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62 |
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63 externC void |
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64 cyg_package_start( void ) |
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65 { |
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66 cyg_iso_c_start(); |
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67 } // cyg_package_start() |
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68 |
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69 int |
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70 main(int argc, char *argv[]) |
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71 { |
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72 #if TEST_VALID |
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73 int i; |
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74 int r, prev, prevprev; |
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75 int how_many_periodics = 0; |
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76 #endif |
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77 |
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78 CYG_TEST_INIT(); |
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79 |
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80 CYG_TEST_INFO("Starting tests from testcase " __FILE__ " for C library " |
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81 "rand() function"); |
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82 |
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83 CYG_TEST_INFO("This test tests the distribution of random numbers and"); |
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84 CYG_TEST_INFO("may take some time"); |
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85 |
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86 #if TEST_VALID |
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87 r = rand() % 2; |
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88 prev = r; |
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89 r = rand() % 2; |
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90 for (i = 0; i < TEST_LENGTH; ++i) { |
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91 prevprev = prev; |
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92 prev = r; |
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93 r = rand() % 2; |
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94 if (r == prevprev) { |
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95 ++how_many_periodics; |
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96 } |
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97 if (how_many_periodics > (2*TEST_LENGTH)/3) { |
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98 break; |
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99 } |
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100 } |
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101 |
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102 CYG_TEST_PASS_FAIL( (how_many_periodics <= (2*TEST_LENGTH)/3), |
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103 "periodicity of rand() in lowest bit"); |
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104 |
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105 #else |
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106 |
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107 // FIXME: should be an _expected_ fail i.e. XFAIL |
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108 CYG_TEST_NA("Chosen rand algorithm is known to fail this test"); |
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109 |
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110 #endif |
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111 |
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112 CYG_TEST_FINISH("Finished tests from testcase " __FILE__ " for " |
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113 "C library rand() function"); |
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114 } // main() |
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115 |
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116 |
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117 // EOF rand4.c |
