Re: Does an enhanced //e _ALWAYS_ have 80 col. support?

[Andy McFadden <fadden@fadden.com>]

Don Bruder <dakidd@sonic.net> wrote:
> Right, that's what I was referring to. When in doubt, the "rule" I 
> always knew was "read unless specifically told otherwise". 

Apple II reference manual (1981 edition), page 20:

  A program can "reference" the address of the special location for the
  speaker by performing a "read" or "write" operation to that address.
  The data which are read or written are irrelevant, as it is the
  _address_ which throws the switch.  Note that a "write" operation on the
  Apple's 6502 microprocessor actually performs a "read" before the
  "write", so that if you use a "write" operation to flip any soft
  switch, you will actually throw that switch _twice_.  For toggle-type
  soft switches, such as the speaker switch, this means that a "write"
  operation to the special location controlling the switch will leave
  the switch in the same state it was in before the operation was
  performed.

I just now tried a very simple sound loop on a real IIgs.  There was no
difference for "LDA $C030" vs. "STA $C030".

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