void abort() { }; extern unsigned __VERIFIER_nondet_uint(); void assume_abort_if_not(int cond) { if(!cond) {abort();} } /*@ requires (((1 <= counter) && (1 <= \old(cond)))) && (cond != 0); ensures (((1 <= counter) && (1 <= \old(cond)))) && (1); @*/ void __VERIFIER_assert(int cond) { if (!(cond)) { ERROR: {/*@ assert(0); */;} } return; } int counter = 0; /*@ requires ((counter == 0)); ensures ((\old(counter) == 0)); @*/ int main() { unsigned A, B; unsigned q, r, b; A = __VERIFIER_nondet_uint(); B = 1; q = 0; r = A; b = B; /*@ loop invariant (((\old(counter) == 0) && ((((A == r) && (counter == 0)) && (q == 0)) || (((A == r) && (1 <= counter)) && (q == 0))))); @*/ while (counter++<1) { if (!(r >= b)) break; b = 2 * b; } /*@ loop invariant (((((A == r) && (1 <= counter)) && (\old(counter) == 0)) && (q == 0))); @*/ while (counter++<1) { __VERIFIER_assert(A == q * b + r); if (!(b != B)) break; q = 2 * q; b = b / 2; if (r >= b) { q = q + 1; r = r - b; } } __VERIFIER_assert(A == q * b + r); return 0; }