Quick Start on an HP 21MX Minicomputer
======================================

  00 - power on the machine
  01 - turn the key to “R” to reset the machine and then over to “OPERATE”
  02 - hit “HALT” and then “PRESET” for good measure
  03 - use arrows to select “M” register (memory address)
  04 - enter the starting memory address (example: 000100 for 00100)
  05 - press “STORE”
  06 - use arrows to select “T” register (contents of the memory address)
  07 - enter one instruction (example: 002004)
  10 - press “STORE” (also increments M)
  11 - repeat steps 07 and 10 for each instruction
  12 - go back to step 03 for non-sequential memory addresses (ex: 77770)
  13 - use arrows to select “P” register
  14 - enter the program start address
  15 - press “STORE”
  16 - press “RUN”

Entering Octal values
=====================

The display shows all binary bits divided into sets of 3 bits. This is called octal.
Listings use octal both for memory locations and for assembly instructions. Here is
a mapping of octal to binary bits:

  0 – 000
  1 – 001
  2 – 010
  3 – 011
  4 – 100
  5 – 101
  6 – 110
  7 - 111

Sample Listing
==============

  0001                ASMB,A,B,L

  0003* Binary counter on the S register
  0004* by Tim Riker <Tim@Rikers.org>
  0005* public domain

  0007                      HED ** binary counter **
  0008  00100               ORG 100B

  0010* could CLA here, but stay small. =)
  0011  00100 002004  LOOPA INA          Increment A
  0012  00101 102601        OTA 1        Write to S
  0013* leave a ton of NOPs to slow us down
  0014* adjust ORG here if you have less than 32Kw
  0015  77770               ORG 77770B
  0016  77770 024100        JMP LOOPA    Jump to the increment loop
  LOOPA 000100   01/0011 -- 01/0016
  1 symbols
  16 lines assembled, 3 words generated
  0 errors, 0 warnings