To AGA or to OCS/ECS...

bitter · 23 October 2018, 01:56

I'm a long-time 6502 coder, and finally decided to move up to a 68k world. I got a nice Amiga 1200, and set out to find all the documentation I can on the computer... only to realize that there really isn't that much on the AGA chipset.

This makes me ask the question - for somebody just diving into Amiga assembly/hardware coding, would I be better off with an Amiga 500/600 instead? There is so much more documentation available, and it's still a huge step up from a Commodore 64. I would like to get some opinions for long-time users and hopefully from people that did similar plunge like me? Don't want to invest a lot of time into the AGA and hit a wall because I don't have the experience behind me...

Thanks for any input!

arcanist · 23 October 2018, 02:12

This is the best programmer's overview of the changes in AGA I've found.

It assumes prior knowledge of the OCS chipset so I would start there first. The official Hardware Reference Manual covers OCS in detail. It's available online in various forms and as a book if you're willing to spend a bit.

meynaf · 23 October 2018, 08:58

Quote:

Originally Posted by bitter

This makes me ask the question - for somebody just diving into Amiga assembly/hardware coding, would I be better off with an Amiga 500/600 instead?

Your A1200 is fine for doing ECS too. So you can start with that.
Then AGA isn't a huge step, differences are minor - basically you just have more available colors.

alpine9000 · 23 October 2018, 10:23

WinUAE source code is a good reference for chipset behavior.

StingRay · 23 October 2018, 10:26

Start with the basic OCS stuff as already said. Your 1200 is fine for that, just make sure certain AGA specific registers (FMODE, BPLCON4 etc.) are set to OCS values to aoid display problems, information about that can be easily found online. Once you understand OCS you can move to AGA if you want.

bitter · 23 October 2018, 14:47

Thanks for the feedback! The more I read up on AGA, the more I realize that as you guys mentioned the difference really isn't that huge, outside of more colors and higher bandwidth.

Off to OCS world I go. Going from 3 8-bit to 15 32-bit registers is quite a trip all by itself...

Tigerskunk · 02 December 2018, 07:06

Just dropping by to say: have fun with OCS...

And let us know what you are cooking up...

23 October 2018, 01:56	#1
bitter Registered User Join Date: Oct 2018 Location: Fort Mill, SC, US Posts: 83	To AGA or to OCS/ECS... I'm a long-time 6502 coder, and finally decided to move up to a 68k world. I got a nice Amiga 1200, and set out to find all the documentation I can on the computer... only to realize that there really isn't that much on the AGA chipset. This makes me ask the question - for somebody just diving into Amiga assembly/hardware coding, would I be better off with an Amiga 500/600 instead? There is so much more documentation available, and it's still a huge step up from a Commodore 64. I would like to get some opinions for long-time users and hopefully from people that did similar plunge like me? Don't want to invest a lot of time into the AGA and hit a wall because I don't have the experience behind me... Thanks for any input!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
AGA first or OCS/ECS?	Spec-Chum	Coders. General	18	29 December 2016 16:46
PacMan '96 - AGA or OCS/ECS?	liviux76	support.Games	32	19 November 2016 18:50
AGA Upgrade for ECS/OCS Games?	slowtide	project.Amiga Game Factory	3	03 December 2013 20:11
OCS/ECS , AGA Diffrencies	Kyon	New to Emulation or Amiga scene	7	10 June 2009 11:43
ecs ocs games on aga	memothejanitor	support.Apps	4	16 June 2007 04:30

23 October 2018, 02:12	#2
arcanist Registered User Join Date: Dec 2017 Location: Austin, TX Age: 41 Posts: 405	This is the best programmer's overview of the changes in AGA I've found. It assumes prior knowledge of the OCS chipset so I would start there first. The official Hardware Reference Manual covers OCS in detail. It's available online in various forms and as a book if you're willing to spend a bit.

23 October 2018, 10:23	#4
alpine9000 Registered User Join Date: Mar 2016 Location: Australia Posts: 881	WinUAE source code is a good reference for chipset behavior.

23 October 2018, 10:26	#5
StingRay move.l #$c0ff33,throat Join Date: Dec 2005 Location: Berlin/Joymoney Posts: 6,863	Start with the basic OCS stuff as already said. Your 1200 is fine for that, just make sure certain AGA specific registers (FMODE, BPLCON4 etc.) are set to OCS values to aoid display problems, information about that can be easily found online. Once you understand OCS you can move to AGA if you want.

23 October 2018, 14:47	#6
bitter Registered User Join Date: Oct 2018 Location: Fort Mill, SC, US Posts: 83	Thanks for the feedback! The more I read up on AGA, the more I realize that as you guys mentioned the difference really isn't that huge, outside of more colors and higher bandwidth. Off to OCS world I go. Going from 3 8-bit to 15 32-bit registers is quite a trip all by itself...

02 December 2018, 07:06	#7
Tigerskunk Inviyya Dude! Join Date: Sep 2016 Location: Amiga Island Posts: 2,770	Just dropping by to say: have fun with OCS... And let us know what you are cooking up...

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)