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AuthorTopic: Why is AGA so hard to implement?  (Read 276 times)

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Offline psxphill

Re: Why is AGA so hard to implement?
« Reply #15 on: March 25, 2018, 10:21:24 PM »
Quote from: Chucky;837792
that exactly ZERO software will use anyway..  so.. no reason

I believe it's possible to write software.

Quote from: NorthWay;837835
Mh. Depends on your definition of planar.
Byteplanes have been tossed around several times - one pointer for R/G/B each, saving 25% bandwidth. But yes, I agree with your sentiment.

I suspect that causes more problems than it solves for bandwidth. RAM is really fast if you only read sequentially. As soon as you start reading from three different places in RAM it will slow down or you would need to implement burst caches. Which will add a small amount of latency.

I agree it would save RAM when using 24 bit displays, but 16 bit is pretty good at saving RAM too. Just say the extra 8 bits are alpha when using a genlock and move on.
« Last Edit: March 25, 2018, 10:28:14 PM by psxphill »
 

Offline Hattig

Re: Why is AGA so hard to implement?
« Reply #16 on: March 26, 2018, 10:47:56 AM »
Quote from: NorthWay;837835
Mh. Depends on your definition of planar.
Byteplanes have been tossed around several times - one pointer for R/G/B each, saving 25% bandwidth. But yes, I agree with your sentiment.

(Ok, one last option: 10 bits planar for HAM10?)


Why, in 2018? Sure, back in the day HAM10 could have been really nice (256 base colours, and true 24-bit (albeit fringed) imagery). But today, memory is cheap, bandwidth is cheap.

It seems to me that an AGA extension today should take advantage of modern memory's burst modes (just like AGA itself increased bandwidth/clock over OCS), and even in an FPGA implementation with limited DDR2/3 memory controller, you could get order of magnitude bandwidth improvements for the graphics system over AGA. Which would mean existing AGA would be unleashed, but also you can implement higher resolutions and higher bit-depths (and if you like: more, larger, more colourful sprites; or more, higher-resolutions, more colourful playfields).
 

Offline Chucky

Re: Why is AGA so hard to implement?
« Reply #17 on: March 26, 2018, 04:12:06 PM »
Quote from: psxphill;837838
I believe it's possible to write software.


well..  yes.  but then we are in the situation that most sources is gone.  so completly NEW software must be made..  and why do it to a small platform. better support RTG and lots of different hardware is supported directlty..  so pointless thing to do simply...
 

Offline Zooz

Re: Why is AGA so hard to implement?
« Reply #18 on: March 26, 2018, 04:41:27 PM »
That is only a matter of pleasure for a coder to play with new stuff. It can be seen as nonsense or not. But a hobby do not needs excuses. For larger audience, indeed RTG is better choice. For the fun, one can appreciate.
 

Offline gregthecanuck

Re: Why is AGA so hard to implement?
« Reply #19 on: March 26, 2018, 07:51:53 PM »
Quote from: Hattig;837846


... in an FPGA implementation with limited DDR2/3 memory controller, you could get order of magnitude bandwidth improvements for the graphics system over AGA.


Actually with Vampire it's two orders of magnitude. Roughly 600MB/s.  :)