Couple simple things what could make STE better

No topic. Everything you want to speak about. Please just stay courteous.

Moderators: Mug UK, Silver Surfer, Moderator Team

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Couple simple things what could make STE better

Postby AtariZoll » Wed Jul 12, 2017 7:05 am

STE HW scroll settings work for whole screen. It is possible to make some part of screen static, but is not easy, and is very timing critical. And splitting is possible only vertically.
Much better would be if designers added settings for window which scrolls, and rest of screen would be static. That would require not so complex logic, and 4 registers for setting pos. and dimensions.

2 audio channels can not be addressed separately - they are interleaved as left and right channel.
Better would be 2 separated and independently controllable channels. Then music could go on one, and effects on other. Actually, it is possible with interleaved channels too, but costs too much CPU time to constantly update effect channel.
Here need to mention bad audio mixer ratio too - what would be design error rather. With 2 independent channels there should be option to mix both in mono.

It is nice that there are sockets for RAM, and would be even more nice to see some expansion port.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Cyprian
Atari God
Atari God
Posts: 1405
Joined: Fri Oct 04, 2002 11:23 am
Location: Warsaw, Poland

Re: Couple simple things what could make STE better

Postby Cyprian » Wed Jul 12, 2017 8:47 am

BLiTTER Destination DMA currently is used for read and write operations. It could be split into two DMA channels - the one for read, the second one for write. It would allow to use Destination (read) for reading tiles from ram, and Destination (write) for writing to the screen.
Jaugar / TT030 / Mega STe / 800 XL / 1040 STe / Falcon030 / 65 XE / 520 STm / SM124 / SC1435
SDrive / PAK68/3 / CosmosEx / SatanDisk / UltraSatan / USB Floppy Drive Emulator / Eiffel / SIO2PC / Crazy Dots / PAM Net
Hatari / Aranym / Steem / Saint
http://260ste.appspot.com/

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Couple simple things what could make STE better

Postby AtariZoll » Wed Jul 12, 2017 9:26 am

I was thinking about what could make sprite/tile draw faster too. But I see solution different: As it is currently there is:
Reading mask from src, then /AND dest. with it - later means 1 RD and 1WR of dest.
Then reading bitmap data from other src, OR with dest - again 1 RD and 1 WR of dest.
Much faster would be: separated src. address for mask and bitmap. Then could do all it with 2 src RD and 1 dest RD and 1 dest WR.
But I'm not sure that it would fit in "simple thing" definition.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Frank B
Atari Super Hero
Atari Super Hero
Posts: 907
Joined: Wed Jan 04, 2006 1:28 am
Location: Boston

Re: Couple simple things what could make STE better

Postby Frank B » Wed Jul 12, 2017 9:52 am

How about having the blitter calculate the mask on the fly? Ie set a transparent colour or a bit range for all transparent then have the mask generated from it during the blit. That way you can do transparent copies in 12 clock cycles (3 bus cycles). Pixel addressing would be useful too. That would accelerate the VDI.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Couple simple things what could make STE better

Postby AtariZoll » Wed Jul 12, 2017 10:10 am

Frank B wrote:How about having the blitter calculate the mask on the fly? Ie set a transparent colour or a bit range for all transparent then have the mask generated from it during the blit. That way you can do transparent copies in 12 clock cycles (3 bus cycles). Pixel addressing would be useful too. That would accelerate the VDI.

But you need mask immediately at first bit plane, while it can be generated only after reading all 4 bit planes.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Frank B
Atari Super Hero
Atari Super Hero
Posts: 907
Joined: Wed Jan 04, 2006 1:28 am
Location: Boston

Re: Couple simple things what could make STE better

Postby Frank B » Wed Jul 12, 2017 10:57 am

AtariZoll wrote:
Frank B wrote:How about having the blitter calculate the mask on the fly? Ie set a transparent colour or a bit range for all transparent then have the mask generated from it during the blit. That way you can do transparent copies in 12 clock cycles (3 bus cycles). Pixel addressing would be useful too. That would accelerate the VDI.

But you need mask immediately at first bit plane, while it can be generated only after reading all 4 bit planes.


Read source plane1-planex , read dest plane1-planex, calculate mask, write dest plane1-planex.
It works for any operations on more than one plane. I'm talking about adding a stencil transfer feature where any colour index can be set to transparent.

User avatar
Frank B
Atari Super Hero
Atari Super Hero
Posts: 907
Joined: Wed Jan 04, 2006 1:28 am
Location: Boston

Re: Couple simple things what could make STE better

Postby Frank B » Wed Jul 12, 2017 11:45 am

I'd have liked a progressive mode too. That way you can blit all planes in a single line. Less screen shimmer on updates.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Couple simple things what could make STE better

Postby AtariZoll » Wed Jul 12, 2017 11:54 am

OK, understood. But I think that all it would increase gate number in blitter a lot. It was not designed specially for ST type low res.
What I proposed could yet go in simple category. Let's stay at topic - blitter is not STE's new feature. Thread dedicated to blitter can be opened too :D
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Cyprian
Atari God
Atari God
Posts: 1405
Joined: Fri Oct 04, 2002 11:23 am
Location: Warsaw, Poland

Re: Couple simple things what could make STE better

Postby Cyprian » Wed Jul 12, 2017 12:14 pm

- wrong mixing PSG in MC1992 - DMA and PSG should be on the same volume level
- more bitplanes (more colors)
- wider color palette e.g. 15bit (5bit per color channel)
- video border on/off
- hardware video interlace
Jaugar / TT030 / Mega STe / 800 XL / 1040 STe / Falcon030 / 65 XE / 520 STm / SM124 / SC1435
SDrive / PAK68/3 / CosmosEx / SatanDisk / UltraSatan / USB Floppy Drive Emulator / Eiffel / SIO2PC / Crazy Dots / PAM Net
Hatari / Aranym / Steem / Saint
http://260ste.appspot.com/

swapd0
Atari User
Atari User
Posts: 42
Joined: Thu Dec 13, 2007 8:56 pm

Re: Couple simple things what could make STE better

Postby swapd0 » Wed Jul 12, 2017 4:40 pm

- chunky mode
- 15 or 16 bit palette

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Couple simple things what could make STE better

Postby AtariZoll » Tue Jul 18, 2017 7:17 am

I don't think that more bitplanes would be simple - that needs bigger video RAM, so complete rework of MMU and RAM access logic, sharing of RAM between CPU and video ...
Wider palette would be not that big deal, but question is would it be really useful with only 16 colors on screen ?

Frank B wrote:I'd have liked a progressive mode too. That way you can blit all planes in a single line. Less screen shimmer on updates.

But it works actually in progressive mode only. There is no proper, by TV standards interlaced video signal generation in case of ST, STE.
If there is interlace, it is on used TV or capture card.

2 things more: 1 byte Scan line word skip register limits scrollable width to 255/80 screen widths, so some 3.5 screens only. There are many games with much wider levels.
Instead Microwire they should use some real mixer chip, where could control (by SW) separated PSG and DMA volumes. That would cost about 2$ more, I guess :D
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Cyprian
Atari God
Atari God
Posts: 1405
Joined: Fri Oct 04, 2002 11:23 am
Location: Warsaw, Poland

Re: Couple simple things what could make STE better

Postby Cyprian » Tue Jul 18, 2017 8:13 am

AtariZoll wrote:I don't think that more bitplanes would be simple - that needs bigger video RAM, so complete rework of MMU and RAM access logic, sharing of RAM between CPU and video ...

CPU cycles are used by FDC/ACSI DMA, therefore could be also used for bitplanes DMA.
Jaugar / TT030 / Mega STe / 800 XL / 1040 STe / Falcon030 / 65 XE / 520 STm / SM124 / SC1435
SDrive / PAK68/3 / CosmosEx / SatanDisk / UltraSatan / USB Floppy Drive Emulator / Eiffel / SIO2PC / Crazy Dots / PAM Net
Hatari / Aranym / Steem / Saint
http://260ste.appspot.com/

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Couple simple things what could make STE better

Postby AtariZoll » Tue Jul 18, 2017 9:05 am

Cyprian wrote:CPU cycles are used by FDC/ACSI DMA, therefore could be also used for bitplanes DMA.

Yes, and that would be serious rework of MMU in first place. Although, if we think little more about :
In PAL mode there is 50 frame/sec, so 50x32KB RAM bandwidth for video, so 1600 KB/sec.
In NTSC it is 60x32KB = 1920 .
In mono 70x32KB = 2240 .
Well, it seems that I was wrong - and actually RAM in ST(E) is enough fast for even 8 bitplanes in low res.
How the Hell nobody came on this before ? Is my calc. correct ?
Now I'm thinking loud, but this is very interesting. Must be possible, since I managed 50 fps video playback in hi-color, where disk bandwith was about 3 MB/sec, but more than 33% of it was for color palette update.

So, if I'm not wrong, it is possible to have 64KB video size, and it can be read without slowing down CPU in low and medium res, unlike on Amiga. Of course, new MMU, shifter is required. It might be tight in NTSC, but in PAL seems plausible.
Idea for video expansion of ST, STE :idea:

P.S. - of course it is not possible with current RAM speed. I forgot about what speed is needed during drive of 1 hor. line. In low. and med. res it is actually as much fast, as much RAM can - in shared mode with CPU. Active part of line is 40 microsecs, and need to read 160 bytes - and that's exactly 4 MB/sec .
What is possible, and actually is not complicated is overscan. And things are that it is possible with ST, but not with STE, where can not access /DE signal.
Last edited by AtariZoll on Tue Jul 18, 2017 4:30 pm, edited 1 time in total.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Frank B
Atari Super Hero
Atari Super Hero
Posts: 907
Joined: Wed Jan 04, 2006 1:28 am
Location: Boston

Re: Couple simple things what could make STE better

Postby Frank B » Tue Jul 18, 2017 4:19 pm

By progressive I mean a multi plane blit where the blitter draws plane 1-n per line. That isn't possible on any multi bitplane resolution if shifting or end masking is required. It means that you get a nasty shimmer effect when scrolling in a text editor. Each plane is blitted a screen at a time.
Hope that makes sense :)

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Couple simple things what could make STE better

Postby AtariZoll » Tue Jul 18, 2017 4:44 pm

Frank B wrote:By progressive I mean a multi plane blit where the blitter draws plane 1-n per line. That isn't possible on any multi bitplane resolution if shifting or end masking is required. It means that you get a nasty shimmer effect when scrolling in a text editor. Each plane is blitted a screen at a time.
Hope that makes sense :)

I don't know it 'progressive' proper term for that. Don't get exactly what you mean with plane 1-n per line. Blitting only 1 whole plane at once, then next plane, and so on ?
When shift is involved you always shift 1 plane at once - best doing it with whole line at once, then can go next line or next bitplane. I don't see why blitter could not do any of ways. But user will see something if blitting is on screen area under drawing. I think that only way to get rid of artefacts is using 2 screen buffers, and doing scroll, blit. on not visible one.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Cyprian
Atari God
Atari God
Posts: 1405
Joined: Fri Oct 04, 2002 11:23 am
Location: Warsaw, Poland

Re: Couple simple things what could make STE better

Postby Cyprian » Tue Jul 18, 2017 4:49 pm

Frank B wrote:By progressive I mean a multi plane blit where the blitter draws plane 1-n per line. That isn't possible on any multi bitplane resolution if shifting or end masking is required. It means that you get a nasty shimmer effect when scrolling in a text editor. Each plane is blitted a screen at a time.
Hope that makes sense :)

actually, you can shift e.g. 4 bitplanes at once with the BLiTTER without that nasty shimmer effect, but IIRC line by line.
Jaugar / TT030 / Mega STe / 800 XL / 1040 STe / Falcon030 / 65 XE / 520 STm / SM124 / SC1435
SDrive / PAK68/3 / CosmosEx / SatanDisk / UltraSatan / USB Floppy Drive Emulator / Eiffel / SIO2PC / Crazy Dots / PAM Net
Hatari / Aranym / Steem / Saint
http://260ste.appspot.com/

User avatar
Frank B
Atari Super Hero
Atari Super Hero
Posts: 907
Joined: Wed Jan 04, 2006 1:28 am
Location: Boston

Re: Couple simple things what could make STE better

Postby Frank B » Tue Jul 18, 2017 6:45 pm

Cyprian wrote:
Frank B wrote:By progressive I mean a multi plane blit where the blitter draws plane 1-n per line. That isn't possible on any multi bitplane resolution if shifting or end masking is required. It means that you get a nasty shimmer effect when scrolling in a text editor. Each plane is blitted a screen at a time.
Hope that makes sense :)

actually, you can shift e.g. 4 bitplanes at once with the BLiTTER without that nasty shimmer effect, but IIRC line by line.


I meant one full plane at a time. The first and last word masks only affect the first and last columns of the screen. If shifting is involved it has to be complete plane updates or per plane per line :)

User avatar
AdamK
Captain Atari
Captain Atari
Posts: 243
Joined: Wed Aug 21, 2013 8:44 am

Re: Couple simple things what could make STE better

Postby AdamK » Tue Jul 18, 2017 7:09 pm

It is possible to program Shifter per line in a timer, so you can have whatever settings you want in each line. A bit of a hassle, but it is possible.
Atari: FireBee, Falcon030 + CT60e + SuperVidel + SvEthlana, TT, 520ST + 4MB ST RAM + 8MB TT RAM + CosmosEx + SC1435, 1040STFM + UltraSatan + SM124, 1040STE 4MB ST RAM + 8MB TT RAM + CosmosEx + NetUSBee + SM144 + SC1224, 65XE + U1MB + VBXE + SIDE2, Jaguar, Lynx II, 2 x Portfolio (HPC-006)

Adam Klobukowski [adamklobukowski@gmail.com]


Social Media

     

Return to “Chat forum [ENG]”

Who is online

Users browsing this forum: No registered users and 1 guest