This is an archived, read-only copy of the United-TI subforum , including posts and topic from May 2003 to April 2012. If you would like to discuss any of the topics in this forum, you can visit Cemetech's
z80 & ez80 Assembly subforum. Some of these topics may also be directly-linked to active Cemetech topics. If you are a Cemetech member with a linked United-TI account, you can link United-TI topics here with your current Cemetech topics.
Z80 & 68k Assembly =>
z80 & ez80 Assembly
| Author |
Message |
|
Iambian
Advanced Member
Joined: 13 Mar 2004
Posts: 423
|
 Posted: 18 Nov 2008 03:53:09 pm Post subject: |
|
|
The aim is to be able to flip flash pages in a multipage flash application without using a romcall or using a RAM-resident routine. The page that is to be swapped in contains an identical run of code in the same exact spot in memory so there shouldn't be any problem performing the operation since after the change, the same instructions are all there.
The question is how actual hardware will respond to swapping a page under those conditions. Will it work? Will the calculator do something odd and crash? If it works, does it do so reliably and on all 83+/84+(SE) ? |
|
| Back to top |
|
|
brandonw
Advanced Member
Joined: 12 Jan 2007
Posts: 455
|
| Posted: 18 Nov 2008 05:01:36 pm Post subject: |
|
|
| The hardware will tolerate that just fine. |
|
| Back to top |
|
|
FloppusMaximus
Advanced Member
Joined: 22 Aug 2008
Posts: 472
|
| Posted: 18 Nov 2008 08:53:51 pm Post subject: |
|
|
| TI does exactly that in the 84+ boot code. |
|
| Back to top |
|
|
benryves
Active Member
Joined: 23 Feb 2006
Posts: 564
|
| Posted: 19 Nov 2008 01:05:58 pm Post subject: |
|
|
Rather than build hardware to lock the first 256 bytes or so of every ROM page so that there's something meaningful on it (so interrupts can be serviced correctly and there's something sensible at $0000 when the system boots with a random page swapped in) I simply stick the same code at the start of every ROM page. Works a treat.  |
|
| Back to top |
|
|
Iambian
Advanced Member
Joined: 13 Mar 2004
Posts: 423
|
| Posted: 19 Nov 2008 06:24:51 pm Post subject: |
|
|
Thank you very much for the responses.
Knowing that I can swap in pages like that with no ill effect eases some worries regarding how my flashapp will turn out. So far, I haven't had to do it yet, but I worry that the content might spill over to a second page. I wanted an easy way for the interrupt (and some of its routines) to stay where it stood and still be able to access all the data it needs, even if it resides on another page. |
|
| Back to top |
|
|
|
Register to Join the Conversation
Have your own thoughts to add to this or any other topic? Want to ask a question, offer a suggestion, share your own programs and projects, upload a file to the file archives, get help with calculator and computer programming, or simply chat with like-minded coders and tech and calculator enthusiasts via the site-wide AJAX SAX widget? Registration for a free Cemetech account only takes a minute.
»
Go to Registration page
