extern void abort(void);
extern void __assert_fail(const char *, const char *, unsigned int, const char *) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__noreturn__));
void reach_error() { __assert_fail("0", "double_req_bl_1071.c", 3, "reach_error"); }

typedef int __int32_t;
typedef unsigned int __uint32_t;

typedef union {
  double value;
  struct {
    __uint32_t lsw;
    __uint32_t msw;
  } parts;
} ieee_double_shape_type;

// nan check for doubles
int isnan_double(double x) { return x != x; }

double trunc_double(double x) {
  int signbit;
  int msw;
  unsigned int lsw;
  int exponent_less_1023;
  do {
    ieee_double_shape_type ew_u;
    ew_u.value = (x);
    (msw) = ew_u.parts.msw;
    (lsw) = ew_u.parts.lsw;
  } while (0);
  signbit = msw & 0x80000000;
  exponent_less_1023 = ((msw & 0x7ff00000) >> 20) - 1023;
  if (exponent_less_1023 < 20) {
    if (exponent_less_1023 < 0) {
      do {
        ieee_double_shape_type iw_u;
        iw_u.parts.msw = (signbit);
        iw_u.parts.lsw = (0);
        (x) = iw_u.value;
      } while (0);
    } else {
      do {
        ieee_double_shape_type iw_u;
        iw_u.parts.msw =
            (signbit | (msw & ~(0x000fffff >> exponent_less_1023)));
        iw_u.parts.lsw = (0);
        (x) = iw_u.value;
      } while (0);
    }
  } else if (exponent_less_1023 > 51) {
    if (exponent_less_1023 == 1024) {
      return x + x;
    }
  } else {
    do {
      ieee_double_shape_type iw_u;
      iw_u.parts.msw = (msw);
      iw_u.parts.lsw = (lsw & ~(0xffffffffu >> (exponent_less_1023 - 20)));
      (x) = iw_u.value;
    } while (0);
  }
  return x;
}

int main() {

  /* REQ-BL-1071
   * The trunc and truncf procedures shall return NaN, if the argument x is NaN.
   */

  double x = 0.0 / 0.0; // NAN

  double res = trunc_double(x);

  // x is NAN the result shall be NAN
  if (!isnan_double(res)) {
    {reach_error();}
    return 1;
  }

  return 0;
}