Re: BRUN HGR pics?

[dalloff@freenet.columbus.oh.us (Dave Althoff)]

Whoops!  I screwed up!

Dave Althoff (dalloff@freenet.columbus.oh.us) wrote:
: Steve Jensen (sjensen@cello.gina.calstate.edu) wrote:
: : I need a program that modifies HGR pics so they can be viewed when
: : BRUN from Applesoft.  I had this years ago but seem to have lost it.
: : Can anyone help?

: You need to append the following code to the beginning of the file:
: (assumes full-page display of HGR Page #1 at $2000)

: 1FF1- 48       PHA
: 1FF2- AD 50 C0 LDA $C050
: 1FF5- AD 52 C0 LDA $C052
: 1FF8- AD 54 C0 LDA $C054
: 1FFB- AD 57 C0 LDA $C057
: 1FFE- 68       PLA
: 1FFF- 60       RTS

: To save the amended file...
: BSAVE IMAGE,A$1FF1,L$200A

Hmmm...That will work, except that it will crash... at least, it will
crash under DOS 3.3.  I don't know if the entry point got moved under
ProDOS, but under DOS 3.3, executable files should end with a JMP $9DBF to
warm-start DOS for a clean re-entry to Applesoft.  I think the same can be
accomplished with a JMP $03D0, and I think that vector still exists under
ProDOS.  So the code should be amended as follows:

 1FF1- AD 50 C0 LDA $C050
 1FF4- AD 52 C0 LDA $C052
 1FF7- AD 54 C0 LDA $C054
 1FFA- AD 57 C0 LDA $C057
 1FFD- 4C D0 03 JMP $03D0

 To save the amended file...
 BSAVE IMAGE,A$1FF1,L$200A

That should solve the problem.  8-)

--Dave Althoff, ][.
-- 
    /-\      Celebrating the International Year of the Roller Coaster
   /XXX\      /X\     /X\_      _     /XX\_      _     _        _____  
  /XXXXX\    /XXX\  _/XXXX\_   /X\   /XXXXX\    /X\   /X\      /XXXXX
_/XXXXXXX\__/XXXXX\/XXXXXXXX\_/XXX\_/XXXXXXX\__/XXX\_/XXX\_/\_/XXXXXX