[duskwuff]

That sort of approach works for some very simple instruction encodings, but doesn't really handle:

1) instructions which "bend" the format, like ARM instructions such as STMIA or B which combine multiple fields to make a larger immediate value or mask.

2) recognizing instructions which use special values in fields (like ARM condition = 1111) to represent a special instruction.

3) instruction encodings with split fields, like the split immediate in RISC-V S-type instructions.

4) instruction encodings which have too many instruction-specific quirks to fit into any reasonable schema, like 68000.