Blogs

All members are invited to blog on Applefritter. Weblogs should generally be of a technical nature and should be written in such a way as to still be readable and useful 50 years from now. Please do not embed outside media. Images and videos can be uploaded via the Media Browser. Files should either be attached to the blog post or uploaded to the file libraries.

When you post to your blog it will appear on this index and on your personal blog page. Once you've made a few posts, contact me about having a graphic added on the top of this page.

The first working(-ish) homemade MMU

Submitted by frozen signal on April 30, 2023 - 7:42am
Back in early march, I dug out my old Apple IIe computer from my parents's garage. That was a fantastic find and I wanted to play again all those games from my childhood. Unfortunately, the computer did not power on. While searching on the internet, I was sidetracked while reading on the MMU and IOU and their lack of replacements. And then I foolishly though that attempting to re-create the MMU and the IOU with a FPGA would be a good idea. Surely, it can't be that hard...
Tags: 
apple IIe MMU

Quick ref: Pass arguments to machine code from the Monitor

Submitted by S.Elliott on April 28, 2023 - 6:18pm
When calling a machine code subroutine from the Monitor, one or two additional arguments can be passed by taking advantage of the way the Monitor uses delimiters to parse arguments from its command-line and stores them in the zero-page pointers A1, A2, A3, A4...in an arbitrarily-strange order:
  • The default argument is always the subroutine address, stored in A1.
  • Appending a '.' delimiter allows another argument to be stored in A2.
  • Inserting a '<' delimiter allows an argument to be stored in A4.
Tags: 
monitor
asm

Apple Presents...Easter Egg!

Submitted by S.Elliott on April 5, 2023 - 5:40pm
Back in 1983, how many users found the secret message in this instructional software?

]BRUN BARGLE

Bargle program by Sue Espinosa

Bargle Bargle Bargle

]

Tags: 
easter egg

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