The   New   Jersey   Machine-Code Toolkit

                            Norman  Ramsey
                    Bell  Communications  Research
 
                         Mary  F.  Fernandez
      Department  of  Computer  Science,  Princeton  University
 
                             Abstract
 
The New Jersey Machine-Code Toolkit helps programmers write
applications that process machine code.  Applications that use the
toolkit are written at an assembly-language level of abstraction, but
they recognize and emit binary.  Guided by a short instruction-set
specification, the toolkit generates all the bit-manipulating code.
 
The toolkit's specification language uses four concepts: fields and
tokens describe parts of instructions, patterns describe binary
encodings of instructions or groups of instructions, and constructors
map between the assembly-language and binary levels.  These concepts
are suitable for describing both CISC and RISC machines; we have
written specifications for the MIPS R3000, SPARC, and Intel 486
instruction sets.

We have used the toolkit to help write two applications: a debugger
and a linker.  The toolkit generates efficient code; for example, the
linker emits binary up to 15% faster than it emits assembly language,
making it 1.7-2 times faster to produce an a.out directly than by
using the assembler.

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