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From: Ivan Godard <ivan@ootbcomp.com>
Newsgroups: comp.compilers
Subject: Re: Best tools for writing an assembler?
Date: Tue, 18 Feb 2014 23:23:29 -0800
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On 2/18/2014 4:04 PM, tpphysik@gmail.com wrote:
> I want to write an assembler for my own processor architecture. It
> would be of middle complexity. ...

I strongly recommend the approach we took in the Mill assembler: we
use the C++ compiler as the first pass, then execute the resulting
program as the second pass. You write a C++ function for each machine
operation: "add(regNum r1, regNum r2)" or whatever. The bodies of each
of these call the emitters with the bit pattern to use, and the
emitters pack the bits into the output.

Note that the C++ forms the meta-language which is traditionally a macro
language. Thus you can rite:
  for(int i=0; i < 8; ++i)
      store(b+4*i, regs[i]);
and get the eight stores to flush your registers.

We actually generate all the function definitions from our specification
machinery, but you can wrte them by hand too, and the work will still be
much less than writing, debugging and documenting a traditional assembler.