Utility to visualize the current state of memory mapping

[dansanderson]

The MEGA65 memory system has many layers and backwards compatibility features, and it is often confusing to understand the current state of the system. I would love an interactive utility that can visualize the current state of memory mapping. Some things an interactive utility can help explain:

• BASIC 65 BANK state, including the special ROM and I/O mapping behaviors of BANK 128
• D030 banking
• KEY register
• Locations of relocatable VIC-IV memory regions
• Other MEGA65 ROM reserved memory regions, e.g. CBDOS and BASIC variable memory in bank 1

If I understand correctly, these are properties that are captured by a freeze state, and so it's appropriate for a freeze utility to offer this as a way to explore a freeze state. Other hardware properties may or may not also be useful (or possible) to represent in such a utility, such as:

• MAP registers
• The presence/absence of RAM expansions such as Attic RAM

I know MAP registers are not available in userland, and are visible in Matrix Mode. If a freezer utility can ask the Hyppo for these values, it could help illustrate the effect of MAP values in a way that Matrix Mode cannot.

I'm imagining this as interactive memory map visualizations. I would love to be able to zoom into address ranges and understand the "state" of a given set of addresses interactively. For example, the next time I forget that I can't POKE $8000,$BB in the default BANK 128 mode, I can open the utility and zoom to $8000 and the tool will visually explain to me what's going on and help me understand what I need to change. This will require some thought and iteration to capture common developer questions and use cases.

[lydon42]

sound like something that could be added to the MONITOR

[lydon42]

Possibly a duplicate of #3

[dansanderson]

Also related: MEGA65/mega65-core#660

A Freezer utility could do it much better than the Monitor because it has access to the environment state and doesn't run in the environment itself. The Monitor can do a few tricks with hardware assistance (e.g. interrupt-frozen registers), but the other aspects of memory and video state mentioned above are lost before entering the monitor. Nothing in userland can access the MAP register.

[dansanderson]

(If you mean the Freezer monitor, then disregard. My comments apply to the MEGA65 Monitor.)

[lydon42]

That's why I linked the other MONITOR issue as an possible duplicate...