SLC Bit Position Instruction

In GE land they have a bit pos (bit position) command. What would be the best approach for doing the same thing in a SLC 5/05?

In GE we use the bit pos to help us trouble shoot HMI commands to verify the proper command is being sent. All our commands are in the %Q file so we just do a bit position for 32 words or how ever large our command table is.

Trying to come up with a good way to duplicate this type of logic using a SLC 5/05. Commands are in a B12 file. Any suggestions or have I missed the obvious?

Are looking to find the bit position of the first bit in the file that is set?

If so, you could look at the FBC instruction. The drawback is that it requires a reference file of the same size as the source.

Paul