Monday, June 18, 2012

New JMON commands and Enhancements

JMON is my machine language monitor program for the Replica 1. While waiting for some parts to arrive for my next hardware project, I recently added a few new features to it:
  1. I added a new Register command. It allows displaying and setting the registers. The register values are used when executing a Go command.
  2. The Fill and Search commands now accept a data pattern of any length (up to 127 bytes).
  3. I added back and debugged some code in the break handler that checks for break versus interrupt and displays a message if the handler was called by an interrupt rather than a BRK instruction.
  4. The Go command now does a JSR (or the equivalent) so the called program can return to JMON.
  5. I removed the reliance on some external Woz Mon routines to make it more portable and use constants for the hardware registers like the keyboard and screen.
  6. I added a new = command that does simple hex math calculations (addition and subtraction of two 16-bit hex numbers). An example where this is useful is when using the CFFA1 flash card and you need to calculate the program length given the start and end addresses.
  7. Added a command to call the ACI (Apple Cassette Interface) firmware, if an ACI card is present.

Several Apple 1 related auctions were recently completed.

An original Apple 1 on eBay sold for US$75,600.

An original Apple 1 auctioned by Sotheby's in New York sold for US$374,500. This is a new record high for an Apple 1.

A Mimeo-1, the Apple 1 reproduction kit by Mike Willegal, sold on eBay for US$2,025. Note that this was a kit that included all parts but needed to be assembled. Mike also just posted on his blog that he will be offering more Mimeo-1 kits and assembled systems.

Just as a point of comparison, the original Apple 1 originally sold new for US$666.66.

Vince Briel of Briel Computers is considering making another run of reproduction Apple 1 Cassette Interface board kits.  He needs 20 people interested in purchasing one to justify a run of boards. E-mail him if you are interested.

While it is Apple II related rather than Apple 1, the long awaited first new book to be published on the Apple II, The New Apple II User's Guide, started shipping this week. I've already ordered a copy and plan to write a review when I finish reading it.

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