The following table presents the functions of the ALU using RTL:

F2 F1 F0     function of ALU        RTL
----------------------------------------
0  0  0      identity A             A
0  0  1      identity TMP           TMP
0  1  0      A and TMP              A & TMP
0  1  1      A or TMP               A | TMP
1  0  0      not A                  -A
1  0  1      A + TMP                A + TMP
1  1  0      A - TMP                A - TMP
1  1  1      unused

These RTL instructions are actually implemented by setting the control points and it is the job of the control unit to implement RTL this way. Each machine instruction of CSC-1 could be written using RTL.