Fixing multiplication in uints

This commit is contained in:
Tomusdrw 2016-01-14 22:02:10 +01:00
parent ca49c6b625
commit b1e986cbdd

View File

@ -145,10 +145,15 @@ macro_rules! construct_uint {
for i in 0..$n_words {
let upper = other as u64 * (arr[i] >> 32);
let lower = other as u64 * (arr[i] & 0xFFFFFFFF);
if i < 3 {
carry[i + 1] += upper >> 32;
ret[i] = lower.wrapping_add(upper << 32);
if i < $n_words - 1 {
carry[i + 1] = upper >> 32;
if ret[i] < lower {
carry[i + 1] += 1;
}
}
ret[i] = lower + (upper << 32);
}
$name(ret) + $name(carry)
}
@ -557,7 +562,9 @@ pub const BAD_U256: U256 = U256([0xffffffffffffffffu64; 4]);
#[cfg(test)]
mod tests {
use uint::U128;
use uint::U256;
use uint::U512;
use uint::FromDecStr;
use std::str::FromStr;
@ -737,6 +744,60 @@ mod tests {
assert_eq!(U256::from(1u64) * U256::from(10u64), U256::from(10u64));
}
#[test]
pub fn uint128_add() {
assert_eq!(
U128::from_str("fffffffffffffffff").unwrap() + U128::from_str("fffffffffffffffff").unwrap(),
U128::from_str("1ffffffffffffffffe").unwrap()
);
}
#[test]
pub fn uint128_add_overflow() {
assert_eq!(
U128::from_str("ffffffffffffffffffffffffffffffff").unwrap()
+ U128::from_str("ffffffffffffffffffffffffffffffff").unwrap(),
U128::from_str("fffffffffffffffffffffffffffffffe").unwrap()
);
}
#[test]
pub fn uint128_mul() {
assert_eq!(
U128::from_str("fffffffff").unwrap() * U128::from_str("fffffffff").unwrap(),
U128::from_str("ffffffffe000000001").unwrap());
}
#[test]
pub fn uint512_mul() {
assert_eq!(
U512::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
*
U512::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap(),
U512::from_str("3fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0000000000000000000000000000000000000000000000000000000000000001").unwrap()
);
}
#[test]
pub fn uint256_mul_overflow() {
assert_eq!(
U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
*
U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap(),
U256::from_str("1").unwrap()
);
}
#[test]
pub fn uint256_mul_overflow2() {
assert_eq!(
U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
*
U256::from_str("2").unwrap(),
U256::from_str("fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe").unwrap()
);
}
#[test]
fn uint256_div() {
assert_eq!(U256::from(10u64) / U256::from(1u64), U256::from(10u64));