in lib/src/sha512_slowsinks.dart [164:170]
void _bsig0(Uint32List word, int offset, Uint32List ret, int offsetR) {
_rotr(28, word, offset, _nums, _sigIndex1);
_rotr(34, word, offset, _nums, _sigIndex2);
_rotr(39, word, offset, _nums, _sigIndex3);
_xor(_nums, _sigIndex2, _nums, _sigIndex3, _nums, _sigIndex4);
_xor(_nums, _sigIndex1, _nums, _sigIndex4, ret, offsetR);
}