This is a page for "David's tracer", a machine-language tracer for the 6502-based 8-bit Apple ][ machines. I release this under the GPL version 2 or greater.
Unlike most machine-language tracers, this one can trace programs that used print-immediate, DOS, and so on. That's because it stored the zero page, manipulated the stack, and had instructions that can cause immediate jumps to subroutines in certain regions (such as those in DOS or ROM). It could even trace itself, by relocating it. Not a big deal today, but useful then.
Here's what is available:
You can also view my home page, or my Apple ][ page.