Re: NEC 78400 (78K.IV)

[Jeffrey A Law <law at cygnus dot com>]

  In message <199810261532.QAA00474@appel.flower>you write:
  > The approach in the i386 backend seems to be to 'define' the register
  > pairs as the true registers (ax,dx,cx), and have aliases for the higher
  > and lower words, ({"ah", 0}, {"al", 0} or something similar).  Something
  > like this doesn't seem fit for the K4, because the 24bit register groups
  > do not cover all registers; and in fact, most operations will be 16 bit
  > anyway.  Therefore, it seems logical to define the K4 as having 8 16bit
  > registers; but how to define the 24bit register groups?
  > 
  > Where can i find more to read on the subject; the md.tex doesn't 
  > seem to address this problem?
I believe you're best off describing the 16bit pairings.  Avoid any 24bit
operations unless absolutely necessary (gcc does not handle ops with a size
that is not 2**n well).

You'll have to experiment some since this target does not match any other
supported targets.

jeff