Author Topic: Level 7 interrupt button (especially for asm coders) (Read 2237 times)

z5 · « **on:** December 03, 2002, 09:57:20 PM »

hi!

For my website (A.D.A.), i try every possible way to capture screenshots from demos. I use Winuae but a lot of demos don't run on it.

There is a program on Aminet called Hrtmon. It's a kind of Action Replay but in software. You load it up, then start the demo, press the right mouse button, you search the copper en save any picture it finds.

There are 2 problems:
- a lot of demos give back garbage or only 3/4 screen or other problems when searching pictures and copper
- with a lot of demos, i can't get into the program with the right mouse button.

In the readme, there is talk about a level 7 interrupt button which you can attach to the trapdoor expansion slot. It should work a lot better than the right mouse button.

Is there anyone who can explain this a bit more. Would this button let me enter all demos? How big is the change that i can find correct screens in demos. (by the way, i allready managed to get screens that way).

Thanks for any help!

xeron · « **Reply #1 on:** December 03, 2002, 10:08:45 PM »

The "Level 7 interrupt" is also known as the NMI, or "Non-Maskable Interrupt". It is the highest priority interrupt, nothing can interfere with it. On the 68K range, there are several interrupt lines, which have a priority. A level 3 interrupt can be interrupted by a level 4 interrupt for example.

Grounding the NMI line with a switch causes the 68K processor to jump to the NMI exception vector. Normally, this would give you a nice GURU alert, but software can patch into the NMI vector and be jumped to when it is triggered, like Hrtmon.

As it is non-maskable, there is not a lot that demos can do to stop it. It is a hardware mechanism completely seperate from the OS.

Hardboy · « **Reply #2 on:** December 03, 2002, 10:58:28 PM »

The button alone will not let you save screenshots of all demos, but it should be possible to get alot of pictures. If you have many years of experince with 68k-assembler, it would be easy to get it in allmost any case (as you would now how to search for screen data). If you get your hardware description of your expansion port/trapdoor/whatever the name is, you can try to locate three outputs called INT0*,INT1*,INT2*. These are the interrupt lines. I´ve short-circuited these with a nail several times, and this will call the level 7-interrup (like pushing the button). Try it out, if you dare!

BTW. Keep up the good work with ADA. It´s a really nice archive. Is there any suggestions page?

Piru · « **Reply #3 on:** December 03, 2002, 11:22:21 PM »

> As it is non-maskable, there is not a lot that
> demos can do to stop it.

One way to stop NMI from working is to have SSP point to odd address (for 68000/68010) or to non-existent memory (68000-68060).

Obviously you can't use any interrupts or exceptions then. :-)

z5 · « **Reply #4 on:** December 04, 2002, 11:11:29 AM »

@Hardboy:

Quote

BTW. Keep up the good work with ADA. It´s a really nice archive. Is there any suggestions page?

Thanks. Any suggestions, just mail them to me (email at contact page on A.D.A.)

@all:
Thanks. I think i will give this a try. Hrtmon manual says that i need pin 80,81 and 82 on my expansion slot. Also, Hrtmon manual says that the level 7 button will work with Asmone. Any tips on that? How should i go about this. Can any one help me a bit more as i don't know anything about assembler code. There really are a lot of fab demos that don't run on winuae like all the TBL demos (tint, glow, captured dreams,...), Gift, Closer,....

Thanks!

Crumb · « **Reply #5 on:** December 04, 2002, 12:18:29 PM »

well... if you don't have luck you may try to connect the composite-video output of your Amiga to a TV card of your pc... It should work, although I guess that the pictures will have poor quality compared to a properly captured ones...

xeron · « **Reply #6 on:** December 04, 2002, 12:22:58 PM »

Yes, asmone supports Level 7 interrupts. When AsmOne is loaded, activating the NMI will get you back to the AsmOne (or AsmPro) command line. Very handy when coding

I don't have an NMI switch myself, but I saw Stingray use one while coding at the Mekka/Symposium 2001.

z5 · « **Reply #7 on:** December 18, 2002, 11:12:06 AM »

if i solder the level 7 interrupt button to the accelerator card (like a Phase 5 68030 or Apollo 68060) instead of the expansion port of the A1200, will this work also?

Author Topic: Level 7 interrupt button (especially for asm coders) (Read 2237 times)

z5

Level 7 interrupt button (especially for asm coders)

xeron

Re: Level 7 interrupt button (especially for asm coders)

Hardboy

Re: Level 7 interrupt button (especially for asm coders)

Piru

Re: Level 7 interrupt button (especially for asm coders)

z5

Re: Level 7 interrupt button (especially for asm coders)

Crumb

Re: Level 7 interrupt button (especially for asm coders)

xeron

Re: Level 7 interrupt button (especially for asm coders)

z5

Re: Level 7 interrupt button (especially for asm coders)