UMX,
 a dynamic compiler for
  the Universal Machine of
   the Cult of the Bound Variable.

(See http://boundvariable.org/um-spec.txt for the machine specification
  or http://boundvariable.org/task.shtml for programs and more context
  or http://boundvariable.org/ for general info.)


Noteworthy optimizations:

* Local constant propagation/folding to make use of immediate operands
  present on modern hardware (including and especially control transfers)

* Global forward zero/nonzero propagation to remove dynamic zeroness
  checks from "load program" and other memory references

* Idiom-recognition for conditional branches

* Local register allocation on low-register host platforms

* Platter-level write-protect and execute-protect of the program array,
  allowing safe efficient support of fine-grained code/data interleaving

* Customized memory allocator with inlined fast-case allocation and freeing

Requires:

* A Unix-like operating system.  (Mostly for mmap(2).)

* Currently, an i386-compatible CPU.  Other architectures are vaguely planned.

* And the makefile kind of assumes GCC flags, but that's easy enough to fix.

How to use:

* If everything works, "make" should build it.

* And then ./umx with one or more program files as arguments.
  (They'll be concatenated -- useful for um.um.)

* Remember to regenerate the makefile when changing dependencies.
  (GNU make should do this automagically.)

Has been run on:

* Linux/{i386,amd64}
* NetBSD/{i386,amd64}
* Solaris/x86_64 (gcc and Sun cc)
* Mac OS X, i386 (but not recently)
* VMware ESXi, with the Linux binary (don't try this at home)