Tools reading binary code, like analysers, debuggers, disassemblers,
etc., need to decode the target's machine code.  A decision tree is
often used to represent the decoding function.

Manually writing a decoder is a lengthy and error-prone task.  It is
desirable to be able to use the vendor's instruction code manual and
to easily transform the documentation into a specification that a tool
can use to generate a decoder.

This paper presents a novel algorithm that computes a decision tree
from machine code bit patterns alone.  Neither the bit fields of the
machine code, nor the width of the machine command, nor the order in
which the bits should be decoded need to be specified.  The decoding
algorithm accesses any significant bit exactly once during decoding.