🚀 go-pugleaf

Mark Huth <mph@behemoth.phx.mcd.mot.com> writes in
Message-ID: <10975@behemoth.phx.mcd.mot.com>

> start:
>     movem.l d0-d7/a0-a6,-(a7)    save regs
>     movea.l AbsExecBase.w,a6    sets exec lib base register
>     callsys SuperState        get into supervisor mode
>     moveq.l #CacheOff,d1        constant to disable cache
>     movec   d1,cacr            write it to the cache control reg
>     callsys UserState
>     movem.l (a7)+,d0-d7/a0-a6
>     rts
>
> ...it's always off to the guru.
> Is there a secret that I'm missing?

The SuperState() & UserState() combo does not work. Use Supervisor() instead:

      movem.l a5,-(sp)
      movea.l ExecBase,a6
      lea.l   1$,a5
      CALLSYS Supervisor
      movem.l (sp)+,a5
      rts
1$
      moveq.l #CacheOff,d1
      move    d1,cacr
      rte

I've written replacement routines for SuperState() & UserState() which I use
in my code. They'll get published eventually. By the way, these two routines
are useful only with compilers which allocate variables on the stack. Lattice
C uses the LINK instruction to reserve space on the stack, and then references
that space through a5, so you do not need the two above routines, just use
Supervisor() instead. Remeber to always inspect the code produced by compilers
if you use assembler stubs with them.

Valentin
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