From: Shawn Jefferson (shawnjefferson_at_24fightingchickens.com)
Date: 2003-09-18 00:17:04
On Wed, 17 Sep 2003 23:41:56 +0200 (CEST), Christian wrote: I agree with you about the way the stack is calculated. The current system makes the most sense with the different configs of Atari out there. We just need some documentation letting people know the quirks of the Atari platform, I guess. >Hmm, I don't think that the stack resides inside your assigned memory >areas. >By default, the runtime assumes the largest possible memory use for >graphics (graphics 9) and adjusts the stack pointer accordingly. So the >stack pointer would initially be around 8k below MEMTOP. Well, when I run my program without _graphmode_used = 0, I get MEMTOP as BC1F and the sp (at $0082 right?) is a couple of bytes below BC1F and as my program runs it gets a few more bytes below that... I was seeing garbage in my bitmap that was changing as my program ran. What I did was to calculate my pointers from MEMTOP. My grid bitmap is now calculated as MEMTOP - 255 - 2560 (64 lines of mode D) and my P/M area is grid_bmp.dat - 2048 & ~2047. This sort of gets around the problem of the stack in upper memory, but my other memory areas are hard-coded still. I guess I should calculate them as well, by the address of the screen ram. Then my program will be able to run on different setups where MEMTOP and screen ram is set differently. Thanks for you help. -- Shawn Jefferson ---------------------------------------------------------------------- To unsubscribe from the list send mail to majordomo_at_musoftware.de with the string "unsubscribe cc65" in the body(!) of the mail.
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