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Re: Incorrect code using gcc 2.8.x for Motorola 5200 Coldfire



  In message <35EBE43E.2CFA37A1@acorn.com>you write:

  > My understanding - which might be quite erroneous - was that QImode
  > operations were allowed to trash the non-QI
  > part of the register, so move.l ad,ad  and  lea i,a could be used
  > for qimode moves to/from an address reg.
  > We can't have movstrictqi though.
That is correct.  I've asked Russ for a clarification on exactly what
is causing the problems.

  > Seems we can allow ri -> a and ri -> d.  Movl a0,d0 isn't going
  > to set the cc right though.
But we should already handle this case since we allow this kind of
stuff on the rest of the m68k family.

  > On the same basis, perhaps add/subqi3 should be allowed to use address
  > regs.
Possible, but unlikley to really help code.  You'll note the move
patterns for !codefire discourage the use of address regs for
byte sized values.


jeff


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