Before: %eax = left, %ebx = right, stack unchanged.
After: with SetULong, %eax = left op right, stack unchanged.
public override sealed void OperateULong(CGenState state) { state.CMPL(Reg.EBX, Reg.EAX); SetULong(state); state.MOVZBL(Reg.AL, Reg.EAX); }