After reset typically ones have to be written into the input and output enable registers (IEN & OEN).
No command exist to set the result register RR to a known state.
The OEN and IEN commands can just write the Data signal to the IEN and OEN registers. In most MC14500 designs the result register RR is externally to the MC14500 fed to an input and can therefore be read and used in commands. This means both operands of a logical operation can be the result register RR. To set the result register RR to 1 and then set OEN and IEN to 1 do:
ORC RR IEN RR OEN RR
RR is the IO address where the RR signal is fed to an MC14500 external input.
ANDC RR would set RR to zero.
A minimalistic init.asm
file looks as follows:
RR EQU 000 Pin RR is wired to input 0 IN1 EQU 001 IN2 EQU 002 OUT0 EQU 000 ORC RR Set RR to 1 IEN RR Enable inputs OEN RR Enable outputs