readme.txt

- Single instruction computer.
- Instruction: subtract and branch if less-than-or-equal-to 0. SUBLEQ
- Example: subleq a b c
   - Subtract value in memory address a from value in memory address b
   - store result in memory address b
   - if the value is less than or equal to 0, jump to c
- Programs are made of groups of 3 values (a, b, c)
- Code and data share the same memory
- A jump to -1 terminates
- A jump to -2 just moves forward to the next
    group of 3 (essentially means "no jump", just continue)
- Writing to address -1 outputs an ascii value

Example:

If we have a piece of subleq code: 9 10 3 11 9 0 12 12 0 14 100 -1 0

It would be executed like this:


9 10 3, 11 9 0, 12 12 0, 14 100 -1, 0
execute at 0
9 10 3, 11 9 0, 12 12 0, 14 86 -1, 0
execute at 3 (not jumping, just moving on)
9 10 3, 11 9 0, 12 12 0, 15 86 -1, 0
execute at 6 (not jumping, just moving on)
9 10 3, 11 9 0, 12 12 0, 15 86 -1, 0
execute at 0 (jumped!)
9 10 3, 11 9 0, 12 12 0, 15 71 -1, 0
execute at 3 (not jumping, just moving on)
9 10 3, 11 9 0, 12 12 0, 16 71 -1, 0
execute at 6 (not jumping, just moving on)
9 10 3, 11 9 0, 12 12 0, 16 71 -1, 0
execute at 0 (jumped!)
9 10 3, 11 9 0, 12 12 0, 16 55 -1, 0
...and so on


I made an attempt at an interpreter in subleq.py

Maybe if I could complete it, I could run the code in flags.sub... I
wonder what it contains?