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Forum: Amiga scene 08 November 2019, 11:53
Replies: 258
Views: 23,858
Posted By chb
What you described is true for D-only blits (see...

What you described is true for D-only blits (see the HRM (http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0127.html) for details). AB->D can use every available memory cycle,...
Forum: Amiga scene 08 November 2019, 00:32
Replies: 258
Views: 23,858
Posted By chb
Idle cycles are cycles the blitter cannot use and...

Idle cycles are cycles the blitter cannot use and are left to the cpu, if requested by it and not used by any other higher priority dma. It gets more complicated because a blitter idle cycle can only...
Forum: Coders. General 07 November 2019, 22:50
Replies: 2,263
Views: 345,385
Posted By chb
AFAIK most A500 from MoBo Rev. 6A on and later...

AFAIK most A500 from MoBo Rev. 6A on and later (probably since around 1989 or so) had some kind of ECS Agnus*. I think memory expansion was by default configured as slow mem, but it was possible to...
Forum: Coders. General 07 November 2019, 21:50
Replies: 2,263
Views: 345,385
Posted By chb
+1 ECS somehow's neither fish nor flesh. ...

+1 ECS somehow's neither fish nor flesh.



AFAIK only the ECS Agnus models can address 1 MB chip mem, so 8372A and above; the original Fat Agnus (8370 and 8371) in the early A500 and A2000...
Forum: Amiga scene 07 November 2019, 12:44
Replies: 258
Views: 23,858
Posted By chb
It actually could be quite useful to maximize...

It actually could be quite useful to maximize memory bandwidth usage. Consider you have a blit running and finishing during bitplane dma - it will steal cycles from the CPU that the CPU could have...
Forum: Coders. Asm / Hardware 06 November 2019, 15:10
Replies: 18
Views: 698
Posted By chb
Have you considered using log tables for...

Have you considered using log tables for multiplication? Like x*y = b^(log_b x + log_b y)? Needs a log table entry for every possible value x or invsqr can take, and an inverse one for every one the...
Forum: Amiga scene 04 November 2019, 23:47
Replies: 99
Views: 5,791
Posted By chb
set;print """ MakeDir RAM:ENV Assign >NIL:...

set;print """
MakeDir RAM:ENV
Assign >NIL: ENV: RAM:ENV
LoadWB
EndCLI >NIL;"""


:D:D:D
(should work with WB 2.1 and above)
Forum: Amiga scene 04 November 2019, 16:24
Replies: 99
Views: 5,791
Posted By chb
Python can be very fast language - in the sense...

Python can be very fast language - in the sense that you're often able to write a program to solve your problem in considerably shorter time than it is possible in e.g. C++, thanks to the features of...
Forum: Coders. General 02 November 2019, 18:26
Replies: 274
Views: 9,679
Posted By chb
If you're on linux, there is xxd, which converts...

If you're on linux, there is xxd, which converts a binary file to a text file containing a C/C++ array of unsigned char and the length as an uint. You then can use the standard #include command.
Forum: Coders. General 01 November 2019, 12:28
Replies: 274
Views: 9,679
Posted By chb
That trick works like this: your empty screen...

That trick works like this: your empty screen consists completely of a pure "modified" color (e.g. setting green to 0x0); you prob. need to take some care of the left border. In that example your...
Forum: Coders. General 01 November 2019, 11:59
Replies: 274
Views: 9,679
Posted By chb
Just to add further to the confusion of "to blit...

Just to add further to the confusion of "to blit or not to blit": I just realized that it may be beneficial to fill the background with the blitter - so sky, the ground and everything that is flat on...
Forum: Coders. General 31 October 2019, 17:49
Replies: 274
Views: 9,679
Posted By chb
Thank you very much for checking!

Thank you very much for checking!
Forum: Coders. General 31 October 2019, 16:13
Replies: 274
Views: 9,679
Posted By chb
I did not test it, but from what Toni said in...

I did not test it, but from what Toni said in this thread and also here (http://eab.abime.net/showthread.php?t=72660), I assumed blitter idle cycles cannot overlap with display dma. Hmm. But there's...
Forum: Coders. General 31 October 2019, 15:08
Replies: 274
Views: 9,679
Posted By chb
It totally wasn't meant as a "told you so!!1!!"....

It totally wasn't meant as a "told you so!!1!!". :) I was just to lazy to type all this again. I really admire your effort - and as you said, it was just theorizing from me, so you are giving us now...
Forum: Coders. General 31 October 2019, 15:06
Replies: 274
Views: 9,679
Posted By chb
AFAIK the catch is that blitter idle cycles...

AFAIK the catch is that blitter idle cycles cannot occur when other dma is going on. So on a 4 bpl display the idle cycles cannot overlap with the bpl dma cycles (but with cpu memory cycles):


B:...
Forum: Coders. General 31 October 2019, 14:48
Replies: 274
Views: 9,679
Posted By chb
Ah right, there was something about those idle...

Ah right, there was something about those idle cycles. :) So during display DMA (4 bpl) blitter in D-only fillmode uses only every 4th DMA cycle, meaning also every 4th DMA cycle (blitter idle cycle)...
Forum: Coders. General 31 October 2019, 14:43
Replies: 274
Views: 9,679
Posted By chb
Just my personal opinion: Using the blitter to...

Just my personal opinion: Using the blitter to fill polygons looks like a nice idea, but in practice it's an inferior method for a game with complex and overlapping objects, as it utilizes memory...
Forum: Coders. General 31 October 2019, 13:58
Replies: 274
Views: 9,679
Posted By chb
I don't think that's a good option if you rely on...

I don't think that's a good option if you rely on the CPU for draw + fill and on the blitter only for clearing. Yes, you have more free dma slots outside the display area, but the CPU can only take...
Forum: Coders. General 29 October 2019, 17:03
Replies: 274
Views: 9,679
Posted By chb
Regarding the speed of the CPU version on the...

Regarding the speed of the CPU version on the 040: Some 040 boards (and I think the original A4000 has one of them) are very slow when accessing chip ram, slower than the 68000 in the A500. If you do...
Forum: Amiga scene 27 October 2019, 19:12
Replies: 968
Views: 54,976
Posted By chb
I totally agree with you that recording samples...

I totally agree with you that recording samples in 8 bit is very difficult, as you need perfect recording levels not to loose even more of the already limited dynamic range. However, that does not...
Forum: Amiga scene 27 October 2019, 14:49
Replies: 968
Views: 54,976
Posted By chb
On the Amiga when using four channels in tracked...

On the Amiga when using four channels in tracked music, you have additional 6 bits for volume per channel, so best practice is using samples normalized to 100% volume and then use the volume...
Forum: support.Other 24 October 2019, 11:53
Replies: 12
Views: 477
Posted By chb
You can also generate background images with the...

You can also generate background images with the copper, with very low horizontal resolution (8 lowres pixels), but all 4096 colors. Some demos used it, mainly for plasma effects.
Forum: Coders. Asm / Hardware 22 October 2019, 16:25
Replies: 21
Views: 1,211
Posted By chb
Very interesting, thanks for the link! So copper...

Very interesting, thanks for the link! So copper position is compared against VHPOS, which can be changed? Didn't know that this is possible!

Are DMA and horizontal display sync also affected? So...
Forum: support.Hardware 19 October 2019, 16:51
Replies: 58
Views: 1,608
Posted By chb
Just a wild guess, but maybe it's a power issue?...

Just a wild guess, but maybe it's a power issue? The 040 draws more power than the 68030, so when doing a HDD access it may overload the (slightly faulty?) power supply and result in unstable...
Forum: Coders. General 19 October 2019, 16:13
Replies: 5
Views: 275
Posted By chb
What the other's said; there's also a simple...

What the other's said; there's also a simple plug-in for gimp that simulates the OCS palette as a filter:
https://github.com/alexalkis/palette_amigaOCS

Can be helpful to quickly check how your...
Forum: Coders. Asm / Hardware 13 October 2019, 10:17
Replies: 21
Views: 1,211
Posted By chb
No. The number of lines per frame is the same.

No. The number of lines per frame is the same.
Forum: Amiga scene 09 October 2019, 16:47
Replies: 258
Views: 23,858
Posted By chb
Yep, I did some experiments with such a setup a...

Yep, I did some experiments with such a setup a while ago. The easiest way IMHO is to use a palette color for every even pixel and modify the green channel for every odd one. That means setting...
Forum: Coders. Asm / Hardware 30 September 2019, 20:32
Replies: 50
Views: 4,374
Posted By chb
Maybe not strictly UHRES related, but as it...

Maybe not strictly UHRES related, but as it concerns ECS and may (or not) give some clues about UHRES, I'll post it here:
I noticed something interesting when having a look with the UAE debugger at...
Forum: Coders. Asm / Hardware 27 September 2019, 10:53
Replies: 50
Views: 4,374
Posted By chb
Modulation of the LPF is something I was thinking...

Modulation of the LPF is something I was thinking of also. The output however may be a bit hard to predict (and varying between models). Best thing to check probably would be either an Amiga with an...
Forum: Coders. Asm / Hardware 24 September 2019, 13:17
Replies: 50
Views: 4,374
Posted By chb
This won't work, how could it? The maximum DMA...

This won't work, how could it? The maximum DMA sample rate* is tied to the horizontal frequency (max. two samples per channel are loaded at the beginning of each scanline). The first patch you linked...
Forum: Coders. Asm / Hardware 24 September 2019, 10:46
Replies: 50
Views: 4,374
Posted By chb
As the majority of these registers...

As the majority of these registers (pointers/modulo/identifiers) was probably never used by anything, and will not be used in the future, there shouldn't be a problem to reuse them in case you'd want...
Forum: Coders. Asm / Hardware 14 September 2019, 15:53
Replies: 50
Views: 4,374
Posted By chb
Right, I think UHRES is not that important! ;) ...

Right, I think UHRES is not that important! ;)


From the documentation it seems to me like it triggers a vblank somewhere in the middle of the standard display, to allow higher display refresh...
Forum: Coders. Asm / Hardware 14 September 2019, 15:39
Replies: 50
Views: 4,374
Posted By chb
Yeah, I know, but I did not realize that it's not...

Yeah, I know, but I did not realize that it's not limited to 56 kHz. :) And that it may not be hardwired to display sync if there is a possibility to use the standard sync timing regardless of...
Forum: Coders. Asm / Hardware 14 September 2019, 15:18
Replies: 50
Views: 4,374
Posted By chb
AFAIU, data bus content is not needed, only the...

AFAIU, data bus content is not needed, only the DRAM address bus value if it works like Gorf assumed. RGA value triggers the transfer mode of the VRAM, the address tells the VRAM with ROW to transfer...
Forum: Coders. Asm / Hardware 14 September 2019, 14:26
Replies: 50
Views: 4,374
Posted By chb
@Toni: Great find! To me from your investigation...

@Toni: Great find! To me from your investigation it looks like UHRES is fully implemented and works like documented so far.

Funny how long it has been sitting there without ever being used...
...
Forum: Coders. Asm / Hardware 13 September 2019, 19:35
Replies: 50
Views: 4,374
Posted By chb
Thank you very much for testing! Did you also set...

Thank you very much for testing! Did you also set bit 9 in DMACON to enable UHRES dma?
http://amiga-dev.wikidot.com/hardware:dmaconr


Hmm, according to the documentation $78 belongs to sprite...
Forum: Coders. Asm / Hardware 11 September 2019, 13:13
Replies: 50
Views: 4,374
Posted By chb
Yes, but the A2024 has it's own memory for a...

Yes, but the A2024 has it's own memory for a complete frame (unlike Graffiti etc.) and it is VRAM-based, so it might have been an related for UHRES or some parts of it were supposed to be used in the...
Forum: Coders. Asm / Hardware 09 September 2019, 11:00
Replies: 50
Views: 4,374
Posted By chb
True, I conveniently forgot about that. :) ...

True, I conveniently forgot about that. :)


If you refer to the sprite pointers: They come out twice in every UHRES cycle (so two sprite addresses for one BPL address). So one can speculate if...
Forum: Coders. Asm / Hardware 08 September 2019, 18:02
Replies: 50
Views: 4,374
Posted By chb
After thinking about it again I suppose you're...

After thinking about it again I suppose you're right, the whole setup makes only sense when chipram = vram (or at least a part of it). I guess it works the following way:

1) VRAM is essentially...
Forum: Coders. Asm / Hardware 08 September 2019, 10:59
Replies: 50
Views: 4,374
Posted By chb
I think there's a more mundane explanation to...

I think there's a more mundane explanation to UHRES than the mythical ranger chipset.

Commodore did in fact produce a VRAM device already in 1988, and that's been the A2024 monitor. Here...
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