Programs were written in machine code using absolute addressing and hexadecimal representation. Arithmetic was fixed point requiring explicit scaling by shifting the numbers. A word normally held two instructions. Below is a program written on a coding sheet for channel I that holds the words 00 - 1F. The second address above a word is the address to the right half of the word.
00 80 01 81 02 82 03 83 7901 6102 Number 1 Number 2 Sum store 04 84 05 85 06 86 07 87 4903 1B00 0000 0000 0000 0000 0000 0000 ... 1c 9C 1D 9D 1E 9E 1F 9F 0000 0000 0000 0000 0000 0000 0000 0000
The program adds the two numbers stored in the words 01 and 02 and stores the result in 03:
Copy (79) the number in 01 to A; Add (61) the number in 02 to A; Store (49) the result in 03; Stop (1B).