// 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 unsigned int __VERIFIER_nondet_uint(void); //@ requires true; //@ ensures true; void assume_abort_if_not(int cond) //@ requires true; //@ ensures (cond != 0); { if(!cond) {abort();} } void __VERIFIER_assert(int cond) //@ requires (cond != 0); //@ ensures (cond != 0); { if (!(cond)) { ERROR: {reach_error();} } return; } int main() //@ requires module(hard_ll_valuebound1__verifast_instrumented, true); //@ ensures junk(); { //@ open_module(); unsigned int A, B; long long r, d, p, q; A = __VERIFIER_nondet_uint(); assume_abort_if_not(A>=0 && A<=1); B = __VERIFIER_nondet_uint(); assume_abort_if_not(B>=0 && B<=1); assume_abort_if_not(B >= 1); r = A; d = B; p = 1; q = 0; while (1) //@ invariant (((((((B == 1) && (p == 2)) && (r == 1)) && (A == 1)) && (d == 2)) && (q == 0)) || ((((((B == 1) && (A == r)) && (A <= 1)) && (d == 1)) && (q == 0)) && (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 ((((((((B == 1) && (p == 2)) && (r == 1)) && (A == 1)) && (d == 2)) && (q == 0)) || ((((((B == 1) && (r == 0)) && (A == 1)) && (d == 1)) && (q == 1)) && (p == 1))) || ((((d == B) && (A == r)) && (q == 0)) && (p == 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; }