BASIC's question mark and PRINT

Allison ajp166 at
Tue Nov 22 05:51:39 CST 2005

>Subject: Re: BASIC's question mark and PRINT
>   From: Jim Battle <frustum at>
>   Date: Mon, 21 Nov 2005 23:12:05 -0600
>     To: General Discussion: On-Topic and Off-Topic Posts <cctalk at>
>Rich, if you can get your version 3.2 MS BASIC running on your Altair32 emulator 
>perhaps you can run the program and report what token is used for PRINT.

Altair basic V3.2 at startup looks at the sense switches (port adddress 377Q)
for a value that tells it if the SIO-A, SIO-B or 2SIO is the IO.  The alternate
is to watch it run on the FP and stop it where it loops and look at the IO 
instructions.  Least that how it was done on the real Altair.


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