Altirra 1.3 final released.

[andym00]

There are a couple of reasons that I do this. One is that I have several instruction lists for illegal opcodes and they sometimes have errors or are missing information. It's much easier to deal with this when I have a program that uses the opcode because then the CPU emulation immediately flags the missing opcode and if it's not emulated correctly I know immediately which opcodes to check. If I implement them all at once then I have to trawl through thousands of opcodes of history to figure out what failed. I ran into a problem like this with the DCP opcode and it took me the better part of a day to track down the problem.

 

As for Joyride, I have to take a look, because the version of Joyride that I have works fine. I ran into similar problems with Numen, where it turned out that some versions had a disk loader that was bombing.

 

Don't get me wrong I wasn't criticising you for doing it like that, from reading your blog and your motivations and reasoning for the entire project it makes perfect sense how you're going ahead with it..

And I completely understand your pain with implementing the illegals properly

But once again, thank you so much for Altirra, it an absolute godsend in comparison to Atari800Win

[phaeron]

There are a couple of reasons that I do this. One is that I have several instruction lists for illegal opcodes and they sometimes have errors or are missing information. It's much easier to deal with this when I have a program that uses the opcode because then the CPU emulation immediately flags the missing opcode and if it's not emulated correctly I know immediately which opcodes to check. If I implement them all at once then I have to trawl through thousands of opcodes of history to figure out what failed. I ran into a problem like this with the DCP opcode and it took me the better part of a day to track down the problem.

 

As for Joyride, I have to take a look, because the version of Joyride that I have works fine. I ran into similar problems with Numen, where it turned out that some versions had a disk loader that was bombing.

 

Don't get me wrong I wasn't criticising you for doing it like that, from reading your blog and your motivations and reasoning for the entire project it makes perfect sense how you're going ahead with it..

And I completely understand your pain with implementing the illegals properly

But once again, thank you so much for Altirra, it an absolute godsend in comparison to Atari800Win

 

No sweat.

 

By the way, I checked the link that Heaven/TQA posted, and it appears to be the same version of Joyride that I have, so I don't know why you're having trouble. You do need to make sure you're in PAL mode, as it will *almost* work if you're accidentally in NTSC. Dumb question: Did you reset after mounting the disk? Altirra doesn't auto-reset after opening a disk through that command. It only auto-resets for executables. That's so you can use it to disk swap.

 

As for opcode $CB, it won't be hard to implement. Got an app that uses it? As you correctly guessed, I simply have to add it to the instruction decoder and add a new CPU state for any new cycle operations.

[andym00]

No sweat.

 

By the way, I checked the link that Heaven/TQA posted, and it appears to be the same version of Joyride that I have, so I don't know why you're having trouble. You do need to make sure you're in PAL mode, as it will *almost* work if you're accidentally in NTSC. Dumb question: Did you reset after mounting the disk? Altirra doesn't auto-reset after opening a disk through that command. It only auto-resets for executables. That's so you can use it to disk swap.

 

As for opcode $CB, it won't be hard to implement. Got an app that uses it? As you correctly guessed, I simply have to add it to the instruction decoder and add a new CPU state for any new cycle operations.

 

Bingo! I didn't realise I had to reset after mounting a Disk Image.. I've only been loading XEXs onto it so far which start straight up.. Oops And it makes sense since I was wondering how it would handle a disk swap for Joyride.. Not enough coffee and cigarettes yet this morning

Erm, as for a test app, only have a test harness of the stuff I'm working on that isn't exactly a full on unit test of the instruction But I can put one together for you..