/* hardware integer division program, by Manna returns q==A//B */ void abort() { }; extern void abort(); extern unsigned int __VERIFIER_nondet_uint(); /*@ requires (1); ensures ((cond != 0)); @*/ void assume_abort_if_not(int cond) { if(!cond) {abort();} } /*@ requires ((cond != 0)) && (cond != 0); ensures ((cond != 0)) && (1); @*/ void __VERIFIER_assert(int cond) { if (!(cond)) { ERROR: {/*@ assert(0); */;} } return; } int main() { unsigned int A, B; long long r, d, p, q; A = __VERIFIER_nondet_uint(); assume_abort_if_not(A>=0 && A<=2); B = __VERIFIER_nondet_uint(); assume_abort_if_not(B>=0 && B<=2); assume_abort_if_not(B >= 1); r = A; d = B; p = 1; q = 0; /*@ loop invariant (((((((((d == B) && (A == r)) && (q == 0)) && (1 <= d)) && (A <= 2)) && (p == 1)) || (((((((A == r) && (d == ((long long) 2 * B))) && (p == 2)) && (q == 0)) && (1 <= d)) && (A <= 2)) && (B <= r))) || (((((((0 <= (r + (((__int128) -1 * d) / 2))) && (((__int128) A + d) == ((__int128) ((long long) B * 4) + r))) && (q == 0)) && (p == 4)) && ((A + (d / 2)) == ((__int128) r + ((long long) 2 * B)))) && (1 <= d)) && (A <= 2)))); @*/ while (1) { __VERIFIER_assert(q == 0); __VERIFIER_assert(r == A); __VERIFIER_assert(d == B * p); if (!(r >= d)) break; d = 2 * d; p = 2 * p; } /*@ loop invariant (((((((((((((0 <= r) && (((__int128) r + 1) <= d)) && (((__int128) d + r) == A)) && (((__int128) r + ((long long) 2 * B)) == ((__int128) A + d))) && (q == 1)) && (A <= 2)) && (p == 1)) || ((((((B == 1) && (r == 0)) && (q == 2)) && (p == 2)) && (A == 2)) && (d == 2))) || (((((((A == r) && (d == ((long long) 2 * B))) && (((__int128) r + 1) <= d)) && (p == 2)) && (q == 0)) && (A <= 2)) && (B <= r))) || ((((((B == 1) && (r == 0)) && (q == 2)) && (A == 2)) && (d == 1)) && (p == 1))) || ((((d == B) && (A == r)) && (q == 0)) && (p == 1))) || (((((((0 <= (r + (((__int128) -1 * d) / 2))) && (((__int128) A + d) == ((__int128) ((long long) B * 4) + r))) && (q == 0)) && (p == 4)) && ((A + (d / 2)) == ((__int128) r + ((long long) 2 * B)))) && (1 <= d)) && (A <= 2)))); @*/ while (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; }