Reading the graphics cursor

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senjaz
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Reading the graphics cursor

Post by senjaz » Thu Sep 12, 2019 1:48 pm

My father in law gave me an old BBC User Guide he had found in his loft and one thing led to another and I'm currently learning 6502 assembler with the help of BeebEm.

Although Basic supports reading the text cursor via POS and VPOS, and there is a corresponding OSBYTE call, I can't find any way of reading the current graphics cursor position. There's no documentation in VDU/OSWRCH. I had expected a similar OSWORD call but there is none documented.

Is there a way of getting this information?
Last edited by senjaz on Thu Sep 12, 2019 1:50 pm, edited 1 time in total.

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geraldholdsworth
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Re: Reading the graphics cursor

Post by geraldholdsworth » Thu Sep 12, 2019 2:09 pm

There is bound to be - I don't have the information to hand, but what I do suggest you do is find a copy of the Advanced User Guide and the Master Reference Guides which will give far more detailed information than just the BBC User Guide (I actually found the Electron User Guide to be much better when learning to program than the BBC one!).

You should be able to download them online.
Gerald Holdsworth
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www.reptonresourcepage.co.uk

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dv8
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Re: Reading the graphics cursor

Post by dv8 » Thu Sep 12, 2019 2:41 pm

senjaz wrote:
Thu Sep 12, 2019 1:48 pm
I can't find any way of reading the current graphics cursor position. There's no documentation in VDU/OSWRCH. I had expected a similar OSWORD call but there is none documented.
OSWORD &D (13) returns the last two graphics cursor positions.

It's documented on page 252 of the Advanced User Guide.

senjaz
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Re: Reading the graphics cursor

Post by senjaz » Thu Sep 12, 2019 3:08 pm

dv8 wrote:
Thu Sep 12, 2019 2:41 pm
senjaz wrote:
Thu Sep 12, 2019 1:48 pm
I can't find any way of reading the current graphics cursor position. There's no documentation in VDU/OSWRCH. I had expected a similar OSWORD call but there is none documented.
OSWORD &D (13) returns the last two graphics cursor positions.

It's documented on page 252 of the Advanced User Guide.
Thank you. Quite why the User Guide stops short of documenting the final OSWORD call I don't know.

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jgharston
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Re: Reading the graphics cursor

Post by jgharston » Thu Sep 12, 2019 4:13 pm

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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