1  extern void abort (void);
       2  static void fixnum_neg(signed char x, signed char *py, int *pv)
       3  {
       4    unsigned char ux, uy;
       5  
       6    ux = (unsigned char)x;
       7    uy = -ux;
       8    *py = (uy <= 127) ? (signed char)uy : (-(signed char)(255 - uy) - 1);
       9    *pv = (x == -128) ? 1 : 0;
      10  }
      11  
      12  void __attribute__((noinline)) foo(int x, int y, int v)
      13  {
      14    if (y < -128 || y > 127)
      15      abort();
      16  }
      17  
      18  int test_neg(void)
      19  {
      20    signed char x, y;
      21    int v, err;
      22  
      23    err = 0;
      24    x = -128;
      25    for (;;) {
      26        fixnum_neg(x, &y, &v);
      27        foo((int)x, (int)y, v);
      28        if ((v && x != -128) || (!v && x == -128))
      29  	++err;
      30        if (x == 127)
      31  	break;
      32        ++x;
      33    }
      34    return err;
      35  }
      36  
      37  int main(void)
      38  {
      39    if (sizeof (char) != 1)
      40      return 0;
      41    if (test_neg() != 0)
      42      abort();
      43    return 0;
      44  }
      45