[WP 34S]How to implement an INPUT function

[Marcus von Cube]

RCL αA as a synonym for RCL 01 does not fit easily into our encoding scheme:

• A single command has 16 bits.
• 8 Bits are reserved for the argument in the argument taking commands.
• The command defines whether indirection is supported or not.
• Some commands such as α have special handling.
• The memory commands allow indirection and local registers which limits the argument range from 0 to 127.
• Local and stack registers are defined by their argument value (from 100 to 127).
• There are many more commands then STO and RCL which deal with registers.
  

There is simply no space in this encoding scheme to add another representation as suggested by you. Another issue would be the user interface on the calculator. You need a way to input such commands...