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GFA BASIC TIPS & TRICKS by Richard Karsmakers

 Some more GfA Basic Tips & Tricks this time.  Hopefully, I won't 
get that much questions anymore that can be traced back to Xbios-
,  BIOS-and GEMDOS calls, because the answers to these can all be 
found in an earlier issue of ST NEWS!

1)  How  can  I  build up a  screen  without  people  seeing  it? 
Afterwards, I want to send it to the visible screen in one time.

Using the Xbios function 5,  you can make the people see a screen 
on which you're not working.  For example,  if you are displaying 
the  screen on &H78000,  you can work on &H70000 by entering  the 
following line:

  Void Xbios(L:&h70000,L:&h78000,W:-1)

The  people will see &h78000 as screen,  but you can now work  on 
&h70000.  You  can simply PRINT,  FILL,  etc.,  and all  will  be 
directed  to the &H70000 address.  If you want to switch  on  the 

screen visibly to &h70000, you should enter:

  Void Xbios(5,L:-1,L:&H70000,W:-1)

A value of '-1' means that the value stays as it was.

2)  How  do I load a program (using EXEC(3,...)) and keep  it  in 
memory, ready to run?

I am afraid nobody knows how to do that.  Even the STRIKE-a-LIGHT 
people  have  had this problem,  and they have not been  able  to 
solve it.  Sorry,  I don't know. But I will get back to this once 
someone has found it out!

3)  How  do I make my computer from 1 to .5  megabyte  using  GfA 

This can be done by entering the following line:

  Spoke &H42F,8

This sets the Physical Top of RAM to &H80000.  To change it  back 
to &H100000, you should use:

  Spoke &H42F,16      !(16=&H10)

Watch out!  The new memory size will continue to be,  also  after 
you  press  reset!  RAM size has to be redefined  or  the  system 
turned off/on to recover.

4) I have problems using the Escape codes. When I use

  Print Chr$(27),"Y",char(31+ILIN),char(31+IKOL)

things go wrong. What must I do?

Everything is simple. Just replace Chr$(27),"Y" by Chr$(27);"Y".

The text of the articles is identical to the originals like they appeared in old ST NEWS issues. Please take into consideration that the author(s) was (were) a lot younger and less responsible back then. So bad jokes, bad English, youthful arrogance, insults, bravura, over-crediting and tastelessness should be taken with at least a grain of salt. Any contact and/or payment information, as well as deadlines/release dates of any kind should be regarded as outdated. Due to the fact that these pages are not actually contained in an Atari executable here, references to scroll texts, featured demo screens and hidden articles may also be irrelevant.