Re: Why is this code exiting to the basic prompt?

[Andy McFadden <fadden@fadden.com>]

BLuRry <brendan.robert@gmail.com> wrote:
> Now, since I'm not seeing a hires screen, I know that the jmp to 400
> never happens.  At least not to the code I saw in the debugger anyway.
> If I press ctrl+reset and then 2400g then I see the game appear and all
> is happy.

[...]
> 248B: LDA $c010 ;clear strobe
> 248E: LDA $c000 ;get key
> 2491: BPL $248E ;wait for keypress
> 2493: LDA $c010 ;clear strobe
> 2496: JMP $2400 ;start game

Put a BRK on the "get key" instruction.  If that succeeds, keep pushing
the BRK out farther until it doesn't get hit.  (This may go faster if
you "binary search" for the farthest point.)

Note that, on the //e and later, hitting the reset key will turn the
language card off, so you always run through $3f2.  It doesn't sound like
you're getting that far, but it is a difference between hitting reset
and calling the reset handler.  (This could actually be used to crack
games -- switch on the alternate 64K bank, boot the game, and hit reset.
You're left back in the main 64K with the game image in the alt bank.)

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