Editing One-instruction set computer (section)

==== Emulation ====
The following program (written in [[pseudocode]]) emulates the execution of a {{mono|subleq}}-based OISC:

<syntaxhighlight lang="c">
 int memory[], program_counter, a, b, c
 program_counter = 0
 while (program_counter >= 0):
     a = memory[program_counter]
     b = memory[program_counter+1]
     c = memory[program_counter+2]
     if (a < 0 or b < 0):
         program_counter = -1
     else:
         memory[b] = memory[b] - memory[a]
         if (memory[b] > 0):
             program_counter += 3
         else:
             program_counter = c
</syntaxhighlight>

This program assumes that {{mono|memory[]}} is indexed by ''nonnegative'' integers. Consequently, for a {{mono|subleq}} instruction ({{mono|a}}, {{mono|b}}, {{mono|c}}), the program interprets {{mono|a < 0}}, {{mono|b < 0}}, or an executed branch to {{mono|c < 0}} as a halting condition.  Similar interpreters written in a {{mono|subleq}}-based language (i.e., [[self-interpreter]]s, which may use [[self-modifying code]] as allowed by the nature of the {{mono|subleq}} instruction) can be found in the external links below.

A general purpose [[Symmetric multiprocessing|SMP]]-capable 64-bit [[operating system]] called '''Dawn OS''' has been implemented in an emulated Subleq machine. The OS contains a [[C language|C]]-like compiler. Some memory areas in the virtual machine are used for peripherals like the keyboard, mouse, hard drives, network card, etc. Basic applications written for it include a media player, painting tool, document reader and scientific calculator.<ref>{{cite web | url=http://users.atw.hu/gerigeri/DawnOS/index.html | title=Dawn for SUBLEQ }}</ref>

A 32-bit Subleq computer with a graphic display and a keyboard called '''Izhora''' has been constructed by [[Yoel Matveyev]] as a large [[cellular automaton]] pattern.<ref>https://www.gazetaeao.ru/zanimatelnaya-nauka-vchera-segodnya-zavtra/ A Russian article on popular science in [[Birobidzhaner Shtern]] with a brief discussion of Yoel Matveyev's Izhora computer</ref><ref>https://habr.com/ru/post/584596/ A description of the virtual computer Izhora on [[Habr]] (in Russian)</ref>