Universal IL Assember

I'm looking for an universal assembler for custom microcode arc开发者_StackOverflowhitectures. Does anyone know of an (open source) application that can take an ASM file, and an architecture definition file of some kind, and emit binary opcodes?

There are a couple of tools like that. The ones I know about:

1. GNU's CGEN, used for a couple of archs in binutils.
2. ArchC Assembler Generator.
3. Various academic tools using Sim-nML language, see e.g. Processor Models for Retargetable Tools