// verifast_options{disable_overflow_check target:ILP32}
/*
  hardware integer division program, by Manna
  returns q==A//B
  */

extern void abort(void);
//@ requires true;
//@ ensures true;
void reach_error()
//@ requires false;
//@ ensures true;
{}extern int __VERIFIER_nondet_int(void);
//@ requires true;
//@ ensures true;
void assume_abort_if_not(int cond) 
//@ requires true;
//@ ensures true;
{  if(!cond) {abort();}
}
void __VERIFIER_assert(int cond) 
//@ requires (cond != 0);
//@ ensures (cond != 0);
{    if (!(cond)) {
    ERROR:
        {reach_error();}
    }
    return;
}

int main() 
//@ requires module(hard2__verifast_instrumented, true);
//@ ensures junk();
{
    //@ open_module(); 
    int A, B;
    int r, d, p, q;
    A = __VERIFIER_nondet_int();
    B = 1;

    r = A;
    d = B;
    p = 1;
    q = 0;

while (1)
//@ invariant ((((((((A == r) && ((A + d) == (p + r))) && (8 <= p)) && (q == 0)) && (B == 1)) || ((((((A == r) && (p == 2)) && (1 <= r)) && (d == 2)) && (q == 0)) && (B == 1))) || ((((((A == r) && (d == 4)) && (2 <= r)) && (q == 0)) && (B == 1)) && (p == 4))) || (((((A == r) && (d == 1)) && (q == 0)) && (B == 1)) && (p == 1)));
    {
        __VERIFIER_assert(q == 0);
        __VERIFIER_assert(r == A);
        __VERIFIER_assert(d == B * p);
        if (!(r >= d)) break;

        d = 2 * d;
        p = 2 * p;
    }

while (1)
//@ invariant ((((A == (q + r)) && (d == p)) && (1 <= p)) && (B == 1));
    {
        __VERIFIER_assert(A == q*B + r);
        __VERIFIER_assert(d == B*p);

        if (!(p != 1)) break;

        d = d / 2;
        p = p / 2;
        if (r >= d) {
            r = r - d;
            q = q + p;
        }
    }

    __VERIFIER_assert(A == d*q + r);
    __VERIFIER_assert(B == d);    
    return 0;
}