Does the AGA chipset has been fully exploited ?

[skan]

Originally Posted by kremiso

Another game i would have liked to see in AGA vest is surely Jim Power -...
...
it received also a decent and colorful ms-dos port at the time :
longplay PC
[ Show youtube player ]

in reality i like almost all the ports of this game (and the original of course), so i would like to see a sort of 'back to home' at some point

Yeah, I also wonder if the DOS version would run on a 1200 (maybe with a proper parallax fx too )

Another DOS enhanced game I'd like to see on a 1200 is Turrican 2, pretty colorful and detailed IMHO.

[hitchhikr]

Here they mention (in French) a burst mode for the blitter, is that real or they're just mistaking $dff1fe & the copper burst mode ($dff1fc) ?

http://obligement.free.fr/articles/b...ode_rafale.php

[roondar]

That article is wrong. There is no Blitter burst mode. Then again, there's no Copper burst mode either
Edit: to be clear, you can set the AGA chipset into an increased fetch mode, but that only increases the speed of the reading of bitplane data by Lisa for display. This will impact the Copper and Blitter, but not in the way the article suggests.

[ross]

Originally Posted by hitchhikr

Here they mention (in French) a burst mode for the blitter, is that real or they're just mistaking $dff1fe & the copper burst mode ($dff1fc) ?

http://obligement.free.fr/articles/b...ode_rafale.php

Yes, it works! But is a bit complex to activate.
The following values must be written in a precise timeline in $dff1fe:

	move.w	#$4255,$dff1fe
	move.w	#$4c4c,$dff1fe
	move.w	#$5348,$dff1fe
	move.w	#$4954,$dff1fe

Then you can enjoy the ultra-secret undocumented 4X blitter burst mode

[roondar]

Originally Posted by ross

Yes, it works! But is a bit complex to activate.
The following values must be written in a precise timeline in $dff1fe:

    move.w    #$4255,$dff1fe
    move.w    #$4c4c,$dff1fe
    move.w    #$5348,$dff1fe
    move.w    #$4954,$dff1fe

Then you can enjoy the ultra-secret undocumented 4X blitter burst mode

Don't be afraid if you can smell the result. That's normal

[hitchhikr]

I thought so (even if that's apparently extracted from "Amiga News" which was a quite serious magazine).

[kremiso]

Originally Posted by hitchhikr

Here they mention (in French) a burst mode for the blitter, is that real or they're just mistaking $dff1fe & the copper burst mode ($dff1fc) ?

http://obligement.free.fr/articles/b...ode_rafale.php

Originally Posted by ross

Yes, it works! But is a bit complex to activate.
The following values must be written in a precise timeline in $dff1fe:

	move.w	#$4255,$dff1fe
	move.w	#$4c4c,$dff1fe
	move.w	#$5348,$dff1fe
	move.w	#$4954,$dff1fe

Then you can enjoy the ultra-secret undocumented 4X blitter burst mode

it is an unexplored feature, or maybe no real benefit could be gained using it?

[dlfrsilver]

Originally Posted by Tsak

Street Fighter Alpha 2 and Street fighter Zero 2 released for the SNES did use the S-DD1 chip. So this might be the source for this mix up.

Very Possibly. Without the S-DD1, SFA2 SFZ2 are no go on SNES.

[roondar]

Originally Posted by kremiso

it is an unexplored feature, or maybe no real benefit could be gained using it?

Ross was joking, there is no unexplored feature (so also no benefit as it doesn't exist ).

[mcgeezer]

Originally Posted by roondar

Ross was joking, there is no unexplored feature (so also no benefit as it doesn't exist ).

No - this is BULLSHIT.

[Tigerskunk]

Originally Posted by ross

Yes, it works! But is a bit complex to activate.
The following values must be written in a precise timeline in $dff1fe:

	move.w	#$4255,$dff1fe
	move.w	#$4c4c,$dff1fe
	move.w	#$5348,$dff1fe
	move.w	#$4954,$dff1fe

Then you can enjoy the ultra-secret undocumented 4X blitter burst mode

Naughty Dog will hate reading this, but I have a working prototype of Uncharted 4 running on an A500 using this trick.

[kremiso]

Originally Posted by roondar

Ross was joking, there is no unexplored feature (so also no benefit as it doesn't exist ).

got the joke, thanks
but now i'm curious what those Ross 4 code lines exactly do, as a non programmer

maybe the Guru Meditation final fix?

[roondar]

Ahh, would've been nice though - undocumented 4x Blitter speed would be the scoop of the century :P

Originally Posted by kremiso

got the joke, thanks
but now i'm curious what those Ross 4 code lines exactly do, as a non programmer

maybe the Guru Meditation final fix?

The write the word BULLSHIT into the non-existent register. So err, nothing

[sokolovic]

Here they also mention this features
https://ada.untergrund.net/?p=boardthread&id=1022

[roondar]

Originally Posted by sokolovic

Here they also mention that features
https://ada.untergrund.net/?p=boardthread&id=1022

It's a bit confusing perhaps, but they're talking about display fetch modes, not a burst mode for the Blitter. AGA does have a display fetch 'burst mode', but like said it doesn't have one for the Blitter.

[sandruzzo]

Blitter Is faster cos you have more dma cycles to use

[sokolovic]

Originally Posted by roondar

It's a bit confusing perhaps, but they're talking about display fetch modes, not a burst mode for the Blitter. AGA does have a display fetch 'burst mode', but like said it doesn't have one for the Blitter.

I'm really not a specialist so indeed that's a bit confusing, especially when they write in this link :

As my demo use any of (what I call) X1,X2 or X4 burst mode,all my aga copperlist start with "fmode,value", simply because everything can be changed each frame.
(actually my fmode values are always or'ed with $00c0 because these bits are the 64 pixel sprite mode, and it doesn't affect the following.)

Why using fmode ? Because with X4 the blitter is 2 times faster, quite faster in X2, and I suspect CPU itself to be faster as far as Chip ram is concerned.

That said, what are the advantadges of the AGA display fetch mode burst mode you mentionned ?

[roondar]

Ok, here's the short form of what's going on:

1. All Amiga's (from A1000 to A4000) have essentially the same Blitter
2. The Blitter has the same speed on all Amiga's.
3. What changes between OCS/ECS/The A3000 and AGA is only how much time the Blitter has to spend waiting on other DMA sources (mostly the display)
4. AGA's higher fetch modes don't speed up the Blitter, they give the Blitter a larger percentage of useful cycles
5. The result of this is that the Blitter can appear to be faster (quite a bit in some cases), but in reality both an A1000 and an A4000 will run the Blitter at the same speed* if the display etc are turned off.

*) Just looking at the Blitter here, not at the faster CPU being able to set up the Blitter faster.

[khph_re]

Sega would definitely have called this 'blast processing' and Sony, 'the emotion engine'

[Antiriad_UK]

Originally Posted by khph_re

Sega would definitely have called this 'blast processing' and Sony, 'the emotion engine'

Haha, I remember the hype for the emotion engine. Genius PR.