modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/execute/ieee/mzero2.c (about)

     1  /* Test IEEE +0/-0 rules */
     2  
     3  static double pzero = +0.0;
     4  static double nzero = -0.0;
     5  static double pinf  = +1.0 / 0.0;
     6  static double ninf  = -1.0 / 0.0;
     7  static double nan   =  0.0 / 0.0;
     8  
     9  void
    10  expect (double value, double expected)
    11  {
    12    if (expected != expected)	/* expected value is Not a number */
    13      {
    14        if (value == value)	/* actual value is a number */
    15  	abort ();
    16      }
    17  
    18    else if (value != value)
    19      abort ();			/* actual value is a NaN */
    20  
    21    else if (memcmp ((void *)&value, (void *)&expected, sizeof (double)) != 0)
    22      abort ();			/* values don't match */
    23  }
    24  
    25  main ()
    26  {
    27    expect (pzero + pzero, pzero);
    28    expect (pzero + nzero, pzero);
    29    expect (nzero + pzero, pzero);
    30    expect (nzero + nzero, nzero);
    31  
    32    expect (pzero - pzero, pzero);
    33    expect (pzero - nzero, pzero);
    34    expect (nzero - pzero, nzero);
    35    expect (nzero - nzero, pzero);
    36  
    37    expect (pzero * pzero, pzero);
    38    expect (pzero * nzero, nzero);
    39    expect (nzero * pzero, nzero);
    40    expect (nzero * nzero, pzero);
    41  
    42    expect (+1.00 * pzero, pzero);
    43    expect (-1.00 * pzero, nzero);
    44    expect (+1.00 * nzero, nzero);
    45    expect (-1.00 * nzero, pzero);
    46  
    47  #ifndef _TMS320C6700
    48    /* C6X floating point division is implemented using reciprocals.  */
    49    expect (pzero / pzero, nan);
    50    expect (pzero / nzero, nan);
    51    expect (nzero / pzero, nan);
    52    expect (nzero / nzero, nan);
    53  
    54    expect (+1.00 / pzero, pinf);
    55    expect (-1.00 / pzero, ninf);
    56    expect (+1.00 / nzero, ninf);
    57    expect (-1.00 / nzero, pinf);
    58  #endif
    59  
    60    exit (0);
    61  }