IBM 5110 APL ROS

From: Christian Corti <cc_at_corti-net.de>
Date: Wed Jul 7 04:11:00 2004

On Tue, 6 Jul 2004, emx wrote:
> I am looking for the APL ROS for a IBM 5110
> Does anyone knows if I stand any chance to find such thing?

If you want to upgrade your BASIC only machine I have to tell you that it
is not sufficient to replace the language card. AFAIK you will also need a
new Executable ROS card because the APL interpreter "interpreter" is
running from Exec ROS and fetching the opcodes of the APL interpreter from
the Language ROS.
BTW it's the same when trying to build a tape drive into a model 2 5110.
This will require a new Exec ROS and a new Base I/O card. I don't know if
adding backplane wires would be needed, too.

But if you are just curious I can send you ROS images of the language ROS.
Making an image from the Executable ROS is not trivial because the
processor can't access this ROS during instruction execution phase,
only during instructions fetches. This is the reason why loading word
constants into registers in ROS code can only be done with LBI,MLH,LBI and
not LWI (i.e. PC relative with postincrement).
For example, to load the constant $A62F into R2 you have to write
LBI R2, #$A6
MLH R2, R2
LBI R2, #$2F

instead of

LWI R2, #$A62F
which means
MOVE R2, (R0)+
DW $A62F <- this is a data word that can't be read from ROS


Christian
Received on Wed Jul 07 2004 - 04:11:00 BST