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.

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

Transmitting a simple datagram via Video Vapor

Submitted by S.Elliott on April 4, 2023 - 5:36pm
Synopsis:
  • Define a short datagram to be transmitted via vapor from visible screen memory.
  • Encode single-cycle accurate video phase via vapor datagram.
  • Construct a routine to receive the vapor datagram and synchronize itself to the video scanner.
  • Write a simple BASIC program to demonstrate all that!
Tags: 
vaporlock
asm

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