English Amiga Board - View Single Post - I am trying to make my first GFX assembler code

roondar · 01 December 2018, 18:47

If you are running with the OS active, you are not allowed to set your own interrupt vectors like that. If you need interrupts while using the OS you have to add your handler to the OS interrupt chain. On the other hand, if you are running with the OS disabled then you can set interrupts however you like, but you can't reliably use OS functions.

I'd guess that changing the level 2 interrupt vector by yourself breaks part of the OS, as it also uses the level 2 interrupt (the level 2 interrupt is the PORTS interrupt, which is stated to be in use by Exec here: http://amigadev.elowar.com/read/ADCD.../node0306.html). I'm almost 100% certain that this interrupt is also in part used by AmigaDOS for reading/writing files and as such the Read() function will hang if you change the vector.

Without meaning this in a negative way, perhaps it's best to learn a bit more about the environment you are using before mucking about with interrupts etc?

AmigaOS is a fully multitasking operating system and you're simply not supposed to address the hardware directly if you wish to use it*. The idea is that you use the available libraries etc to get your desired results. If you do want to use the hardware in a more direct manner, perhaps disabling the OS fits your needs better (though this does mean file I/O becomes much more tricky or impossible unless you either use a trackloader or switch the OS in/out on demand)?

*) Note that with OwnBlitter()/DisownBlitter()/WaitBlitter() you can kinda-maybe-more-or-less get away with your own Blitter programming, but even that is not recommended.

01 December 2018, 18:47	#55
roondar Registered User Join Date: Jul 2015 Location: The Netherlands Posts: 3,423	If you are running with the OS active, you are not allowed to set your own interrupt vectors like that. If you need interrupts while using the OS you have to add your handler to the OS interrupt chain. On the other hand, if you are running with the OS disabled then you can set interrupts however you like, but you can't reliably use OS functions. I'd guess that changing the level 2 interrupt vector by yourself breaks part of the OS, as it also uses the level 2 interrupt (the level 2 interrupt is the PORTS interrupt, which is stated to be in use by Exec here: http://amigadev.elowar.com/read/ADCD.../node0306.html). I'm almost 100% certain that this interrupt is also in part used by AmigaDOS for reading/writing files and as such the Read() function will hang if you change the vector. Without meaning this in a negative way, perhaps it's best to learn a bit more about the environment you are using before mucking about with interrupts etc? AmigaOS is a fully multitasking operating system and you're simply not supposed to address the hardware directly if you wish to use it. The idea is that you use the available libraries etc to get your desired results. If you do want to use the hardware in a more direct manner, perhaps disabling the OS fits your needs better (though this does mean file I/O becomes much more tricky or impossible unless you either use a trackloader or switch the OS in/out on demand)? ) Note that with OwnBlitter()/DisownBlitter()/WaitBlitter() you can kinda-maybe-more-or-less get away with your own Blitter programming, but even that is not recommended. Last edited by roondar; 01 December 2018 at 18:58.