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Forum: Amiga scene Yesterday, 10:21
Replies: 15
Views: 331
Posted By chb
I think there's a misunderstanding what a "purely...

I think there's a misunderstanding what a "purely determinated by technical needs" means in this term. You define it in a very narrow sense it means only things for which no other solution exists....
Forum: Amiga scene 17 September 2020, 15:38
Replies: 15
Views: 331
Posted By chb
AFAIU that does not matter as long as the...

AFAIU that does not matter as long as the motivation for that design is a pure technical one.

Again, AFAIU the design can only be protected if its motivated by something else than a technical...
Forum: Amiga scene 17 September 2020, 14:09
Replies: 15
Views: 331
Posted By chb
At least in Germany designs in the sense of...

At least in Germany designs in the sense of circuit design (meaning the design is fulfilling an exclusively technical function, not an aesthetical one) are not protected by copyright. That's what I...
Forum: Amiga scene 17 September 2020, 09:46
Replies: 15
Views: 331
Posted By chb
It's probably not that clear; AFAIK at least here...

It's probably not that clear; AFAIK at least here in Germany an electronic circuit layout is not protected by copyright law. There are possibilities to protect a design (patents, utility patents),...
Forum: Coders. Asm / Hardware 11 September 2020, 11:38
Replies: 57
Views: 2,227
Posted By chb
Ok, I think I got it thanks to this thread on the...

Ok, I think I got it thanks to this thread on the Atari-Forum (https://www.atari-forum.com/viewtopic.php?f=68&t=30296):

According to that discussion, andi to ccr indeed does three read cycles...
Forum: Coders. Asm / Hardware 09 September 2020, 12:42
Replies: 57
Views: 2,227
Posted By chb
I think it is too exotic, the NXP manual does not...

I think it is too exotic, the NXP manual does not even seem to mention immediate as destination operand. :) In the NXP manual, static to register is listed with 18 clock cycles and 4 memory cycles in...
Forum: Coders. Asm / Hardware 09 September 2020, 11:48
Replies: 57
Views: 2,227
Posted By chb
Ooops :) but then the neogeo dev wiki...

Ooops :) but then the neogeo dev wiki (https://wiki.neogeodev.org/index.php?title=68k_instructions_timings) and the NXP 68000 manual list it with three memory read cycles, compared to two for andi to...
Forum: Coders. Asm / Hardware 09 September 2020, 10:34
Replies: 57
Views: 2,227
Posted By chb
Yeah, but andi to ccr is three, if I'm not...

Yeah, but andi to ccr is three, if I'm not completely mistaken ;)
Forum: Coders. Asm / Hardware 09 September 2020, 09:41
Replies: 57
Views: 2,227
Posted By chb
Hmm, would a btst Dn,#$FF work? It's supposed...

Hmm, would a
btst Dn,#$FF
work? It's supposed to be modulo 8, so for any content of Dn it should clear the Z flag.

It's two words, unfortunately, but that's still a word less than andi to ccr.
Forum: Nostalgia & memories 08 September 2020, 17:06
Replies: 31
Views: 1,817
Posted By chb
The X68000 is a very capable game machine,...

The X68000 is a very capable game machine, without question, but the operating system is rather primitive (Human68k is an MS-DOS look-alike), and while the hardware supports very high resolutions...
Forum: Nostalgia & memories 08 September 2020, 11:12
Replies: 31
Views: 1,817
Posted By chb
AFAIK the Amiga was very rare in Japan,...

AFAIK the Amiga was very rare in Japan, especially in its role as a game/home computer. But apparently it had some niches in the animation/video market.

There's an old thread about Japanese games...
Forum: Coders. Asm / Hardware 05 September 2020, 15:40
Replies: 242
Views: 164,307
Posted By chb
That's interesting! Just to make sure I...

That's interesting! Just to make sure I understand that correctly:

a) Direct colors will be picked from a 3+4 (08 is transparent) color palette like on a 2+2 plane DPF? Also using only palette...
Forum: Retrogaming General Discussion 27 August 2020, 14:44
Replies: 177
Views: 8,580
Posted By chb
Just a small observation concerning blitter...

Just a small observation concerning blitter performance: The bubbles are 16 pixels wide (and high) and fall only in vertical direction, so for every second row they are perfectly aligned to a 16...
Forum: Coders. General 13 August 2020, 13:16
Replies: 27
Views: 1,592
Posted By chb
On AGA you can have pretty much every pixel size...

On AGA you can have pretty much every pixel size you want, but you cannot get past the 57 or so CMOVEs per scanline. So a 200pix wide 2x2 copper chunky is possible, but not a 256 or 320pix wide one....
Forum: Retrogaming General Discussion 07 August 2020, 12:30
Replies: 63
Views: 3,311
Posted By chb
AFAIK Thalion's biggest hit was A320, as dull as...

AFAIK Thalion's biggest hit was A320, as dull as it appears to most people here probably:



Probably also one of the Amiga games with the best sales-to-piracy-ratio. As the Amiga was the first...
Forum: support.Hardware 30 July 2020, 13:16
Replies: 3
Views: 209
Posted By chb
AFAIK the German version had 512k of real fast...

AFAIK the German version had 512k of real fast mem instead of ranger/slow-mem in the Fat Agnus-based US version, so it should perform slightly better in its base configuration.
Forum: Nostalgia & memories 25 July 2020, 23:43
Replies: 216
Views: 22,459
Posted By chb
IMHO a nice option would have been an independent...

IMHO a nice option would have been an independent COP3LC register for blitter queuing that would not have been reset at VBlank. So like having a list of CMOVEs that are executed when the copper isn't...
Forum: Nostalgia & memories 22 July 2020, 13:30
Replies: 216
Views: 22,459
Posted By chb
AFAIK the hackish way the additional color...

AFAIK the hackish way the additional color registers were added is necessitated by the limited RGA bus address space (it only supports up to 256 16-bit registers). I guess it would have been quite...
Forum: Hardware mods 21 July 2020, 14:37
Replies: 4
Views: 685
Posted By chb
As the MB40978P-SH is exactly the same chip as on...

As the MB40978P-SH is exactly the same chip as on the 2.1 revision pictured here (http://amiga.resource.cx/exp/firecracker), and your expansion board fits into three identical-looking sockets, my...
Forum: Coders. Asm / Hardware 06 July 2020, 15:02
Replies: 225
Views: 23,467
Posted By chb
Yes, you can have only 128 individual background...

Yes, you can have only 128 individual background pixels, at least if you don't reload the SPRDAT registers (roondar's approach), which is totally flexible, but costs you quite some performance.
...
Forum: Coders. Asm / Hardware 06 July 2020, 13:04
Replies: 225
Views: 23,467
Posted By chb
Just on a side note: Apidya does have parallax...

Just on a side note: Apidya does have parallax scrolling in the last level (the one with the cogwheels in the bg), and it's pretty impressive - a multiplexed 4 color sprite background, which is even...
Forum: Amiga scene 01 July 2020, 11:25
Replies: 45
Views: 2,488
Posted By chb
It's actually slightly more convoluted. The A500...

It's actually slightly more convoluted. The A500 was the original cost-reduced design. The 2000 exists in two versions: the early A2000-A was designed by Commodore Germany. It was heavily based on...
Forum: Coders. General 31 May 2020, 21:28
Replies: 29
Views: 3,223
Posted By chb
For a span filler and solid polygons the blitter...

For a span filler and solid polygons the blitter is in clearing mode (D only)*, so the idle cycles become relevant, meaning the CPU can work at full speed in parallel to the blitter here if no other...
Forum: Coders. General 31 May 2020, 09:30
Replies: 29
Views: 3,223
Posted By chb
If you by "spinning up the Blitter thousand times...

If you by "spinning up the Blitter thousand times per frame" mean a blitter-based span filler, I do not think that's a feasible approach on the Amiga. For pure clear the CPU is as fast as the blitter...
Forum: Coders. General 31 May 2020, 05:43
Replies: 29
Views: 3,223
Posted By chb
You can do a vertical fill by using 2x the target...

You can do a vertical fill by using 2x the target buffer as source, one line apart, and then use an XOR minterm (but no fill mode). Like D = D ^ (D - 1). It then works like a horizontal blitter fill,...
Forum: Coders. General 02 May 2020, 19:41
Replies: 2
Views: 578
Posted By chb
AFAIU the workings of blitter idle cycles were...

AFAIU the workings of blitter idle cycles were largely undocumented, they appear in some early errata to the HRM, but the later eiditons of the HRM seems to omit them completely:...
Forum: Retrogaming General Discussion 26 April 2020, 20:09
Replies: 26
Views: 2,043
Posted By chb
No problem, I guess I should have been better...

No problem, I guess I should have been better aware of the fact that this is the English Amiga Board after all and that there may be certain sensitivities. ;)
Forum: Retrogaming General Discussion 26 April 2020, 19:27
Replies: 26
Views: 2,043
Posted By chb
And you might want to educate yourself a bit...

And you might want to educate yourself a bit about of the use of irony - it might indicated by the utilization of things like smileys. Also that a sentence is followed by another one beginning with...
Forum: support.Hardware 26 April 2020, 09:59
Replies: 23
Views: 1,670
Posted By chb
There's also a manual on the...

There's also a manual on the BigBookOfAmigaHardware-Page for the 1230-IV:
https://www.bigbookofamigahardware.com/bboah/product.aspx?id=1707

Just a warning, it gives a https certificate error,...
Forum: Retrogaming General Discussion 26 April 2020, 08:07
Replies: 26
Views: 2,043
Posted By chb
That's because there's nothing on the Sinclair...

That's because there's nothing on the Sinclair Spectrum that qualifies as music. :D

But seriously, the AY format seems to be the major one for Spectrums (Spectra?) equipped with something else...
Forum: support.Hardware 25 April 2020, 20:47
Replies: 29
Views: 2,032
Posted By chb
Hmm... I guess BW-composite would be sufficient,...

Hmm... I guess BW-composite would be sufficient, as it would simplify the decoder a lot. I cannot imagine they used the color signal, too. But that's just a guess. Some of the Cinergy hybrid sticks...
Forum: support.Hardware 25 April 2020, 19:38
Replies: 29
Views: 2,032
Posted By chb
Very interesting topic! I cannot contribute any...

Very interesting topic! I cannot contribute any experience with teletext on the Amiga, but if you want to investigate further, maybe get an old USB TV dongle? There are ones that support analog TV...
Forum: Retrogaming General Discussion 25 April 2020, 11:41
Replies: 326
Views: 26,300
Posted By chb
Yes, of course, you're absolutely right. But...

Yes, of course, you're absolutely right. But AFAIK all 030/50 accelerators had standard 70 ns or maybe 60 ns FPM RAM, which is not particulary fast when doing random access table lookups. IRC, that...
Forum: Retrogaming General Discussion 25 April 2020, 08:29
Replies: 326
Views: 26,300
Posted By chb
Those 50 are the screen refresh rate. I was just...

Those 50 are the screen refresh rate. I was just showing that bitplane DMA for a 320*256*8 screen takes ~14% of all available chip memory slots, as roondar claimed. And display fetch is 32 bit,...
Forum: Retrogaming General Discussion 25 April 2020, 00:50
Replies: 326
Views: 26,300
Posted By chb
I'm not roondar, but it is actually quite...

I'm not roondar, but it is actually quite straight forward: The Amiga has 3.58e6 chip ram memory cycles (every second clock cycle). Assuming no other DMA and 8 bytes per mem cycle (32 bit/double...
Forum: Retrogaming General Discussion 22 April 2020, 13:37
Replies: 326
Views: 26,300
Posted By chb
When I look at that game, it seems to me that...

When I look at that game, it seems to me that apart from the cut scenes (and maybe replay) one might get away with rotation around only one axis (y) + zoom, maybe even simplifying perspective...
Forum: Retrogaming General Discussion 21 April 2020, 15:20
Replies: 326
Views: 26,300
Posted By chb
Is that really such a big problem? If we take...

Is that really such a big problem? If we take those 200 quads per player, that's around 200 vertexes if one vertex is shared among 4 quads. Probably 16 bit fixed point is sufficient, so we get...
Forum: Amiga scene 10 April 2020, 19:03
Replies: 1,220
Views: 90,916
Posted By chb
It's exactly what the most successful consolo of...

It's exactly what the most successful consolo of that era, the NES, does - the PPU has analog on-chip composite out, as written already earlier. Were Nintendo/Ricoh engineers "plenty crazy"?
And...
Forum: Amiga scene 10 April 2020, 12:43
Replies: 1,220
Views: 90,916
Posted By chb
Yep, and that's him talking about the NTSC...

Yep, and that's him talking about the NTSC composite signal generation. Nothing lunatic about having it on-chip for a game console/home computer that is connected to a TV set - as written earlier, a...
Forum: Amiga scene 07 April 2020, 14:30
Replies: 1,220
Views: 90,916
Posted By chb
AFAIU they were planning to put NTSC composite...

AFAIU they were planning to put NTSC composite signal generation on-chip, which is in fact a very reasonable choice for a game console. The PPU in the NES/Famicom has analog composite out, the VIC-II...
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