Just an input routine that stores to str7.

The acceptable keys are 0-9, A-F (without pressing alpha,) clear, left, and enter.
When the program starts it prompts to delete str7 if it exists.
  Clear exits the program
  Enter stores the string you typed in
  Left is backspace
  0-9 and A-F are hexadecimal characters

Str7 will start with an AsmPrgm token and have return chars in all the right places.

I wrote this because I didn't like having to press alpha for lettters when
I'm typing hex opcodes into the calculator after TASM gives me a hex file.
Now I just recall str7.

I am not responsible for anything that happens to your calc.

I tested this version and everything works like I want it to so nothing should
happen.