Problem with sim generation

[Ben Elliston]

Hi,

CGEN is bombing when generating a decoder.  Here is some debug info I
emitted from -extract-chunk:
  offset = 16, bits = 4, var-name = word_1, macro? = #t

Then, entering gen-ifetch, my debug output says:
  gen-ifetch: pc 16 4

A bitsize (for the pc?) of 4 doesn't please gen-ifetch, so it stops.  Any
idea how this condition can come about?

Ben