diff options
| -rw-r--r-- | py/mpz.c | 17 | ||||
| -rw-r--r-- | tests/basics/int_big_zeroone.py | 14 |
2 files changed, 29 insertions, 2 deletions
@@ -871,11 +871,17 @@ void mpz_not_inpl(mpz_t *dest, const mpz_t *z) { if (dest != z) { mpz_set(dest, z); } - if (dest->neg) { + if (dest->len == 0) { + mpz_need_dig(dest, 1); + dest->dig[0] = 1; + dest->len = 1; + dest->neg = 1; + } else if (dest->neg) { dest->neg = 0; mpz_dig_t k = 1; dest->len = mpn_sub(dest->dig, dest->dig, dest->len, &k, 1); } else { + mpz_need_dig(dest, dest->len + 1); mpz_dig_t k = 1; dest->len = mpn_add(dest->dig, dest->dig, dest->len, &k, 1); dest->neg = 1; @@ -924,7 +930,14 @@ void mpz_shr_inpl(mpz_t *dest, const mpz_t *lhs, mp_int_t rhs) { round_up = 1; } if (round_up) { - dest->len = mpn_add(dest->dig, dest->dig, dest->len, &round_up, 1); + if (dest->len == 0) { + // dest == 0, so need to add 1 by hand (answer will be -1) + dest->dig[0] = 1; + dest->len = 1; + } else { + // dest > 0, so can use mpn_add to add 1 + dest->len = mpn_add(dest->dig, dest->dig, dest->len, &round_up, 1); + } } } } diff --git a/tests/basics/int_big_zeroone.py b/tests/basics/int_big_zeroone.py new file mode 100644 index 0000000000..e467714bdf --- /dev/null +++ b/tests/basics/int_big_zeroone.py @@ -0,0 +1,14 @@ +# test [0,-0,1,-1] edge cases of bignum + +long_zero = (2**64) >> 65 +long_neg_zero = -long_zero +long_one = long_zero + 1 +long_neg_one = -long_one + +cases = [long_zero, long_neg_zero, long_one, long_neg_one] + +print(cases) +print([-c for c in cases]) +print([~c for c in cases]) +print([c >> 1 for c in cases]) +print([c << 1 for c in cases]) |