UM-32

UM-32 "Universal Machine" is a virtual machine used in the 2006 ICFP Programming Contest. It was supposedly created by an ancient secret society, the Cult of the Bound Variable, in 200 BC. The machine had eight registers, a replaceable codespace, and dynamic memory allocation. The opcodes could refer three registers (indexed A, B, C). The 14 opcodes:

0: if C, A = B
1: A = B[C]  indirect memory load
2: A[B] = C  indirect memory store
3: A = B + C
4: A = B * C
5: A = B / C
6: A = B nand C
7: halt
8: B = allocate C words
9: deallocate C
10: putchar(C)
11: C = getchar()
12: program load: duplicate memory in B into code space, and set instruction pointer to C 
13: A = load immediate (25-bit quantity)

Even more amazing, once the virtual machine was implemented, the remainder of the contest unfolded, uncovering an entire Unix-like operating system (UMIX) containing even more esoteric languages:

QBASIC

The first language encountered was a relatively mundane version of BASIC, but with one evil twist.

All line numbers and numeric literals had to be Roman numerals! One had to extend a corrupted QBASIC program to advance.

2-D

This language was a combination of list processing, Peano numbers, and two-dimensional code.

Given an example that added two Peano numbers, The contest asked you to provide multiplication, list reversal, and a ray tracer.

Peano Addition in 2-D

,....|.............................,
:add v               +----+        :
:*==================*|    v        :
:!send [(N,S),(N,E)]!+  *=====*    :
:*==================* +>!use a!+   :
:++   *==============*| *=====*|   :
-#--->!case W of E, S!+        |   :
:|    *==============*         v   :
:|      |        *================*:
:|      v        !send [(Inl N,E)]!-
:| *============**================*:
:+>!send [(W,E)]!-------------------
:  *============*                  :
,..................................,

External resources

• Main contest site
• Virtual machine specification
• The "Codex", which UM-32 is meant to decode to obtain documents to submit to the contest.

This article is a stub, which means that it is not detailed enough and needs to be expanded. Please help us by adding some more information.