Commit ae6965a4e7

Timon Kruiper <timonkruiper@gmail.com>
2020-04-01 20:40:13
Fix undefined behavior when shift amount is 64
master
1 parent d9cf779
Changed files (1)
src
bigint.cpp
src/bigint.cpp
@@ -1430,7 +1430,7 @@ void bigint_shr(BigInt *dest, const BigInt *op1, const BigInt *op2) {
         uint64_t digit = op1_digits[op_digit_index];
         size_t dest_digit_index = op_digit_index - digit_shift_count;
         digits[dest_digit_index] = carry | (digit >> leftover_shift_count);
-        carry = digit << (64 - leftover_shift_count);
+        carry = (leftover_shift_count != 0) ? (digit << (64 - leftover_shift_count)) : 0;
 
         if (dest_digit_index == 0) { break; }
         op_digit_index -= 1;