// 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; }