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Forum: support.Other 22 November 2021, 20:20
Replies: 7
Views: 471
Posted By Thomas Richter
Some definitions of the components: ...

Some definitions of the components:

Kickstart: That is the resident ROM component, which "kick starts" the entire operating system, but to make the Os complete, it requires disk based components....
Forum: Amiga scene 22 November 2021, 16:52
Replies: 10
Views: 1,072
Posted By Thomas Richter
The best way is to post this into the icomp forum.

The best way is to post this into the icomp forum.
Forum: support.Other 21 November 2021, 17:20
Replies: 248
Views: 40,037
Posted By Thomas Richter
Unfortunately, I cannot really tell you much...

Unfortunately, I cannot really tell you much about Os 4. The PIP support is, however, one of the dark corners of P96 and I hope that I provided with the sample programs and the wiki at iComp some...
Forum: support.Other 21 November 2021, 13:42
Replies: 248
Views: 40,037
Posted By Thomas Richter
No, I'm sorry, as I don't maintain their drivers....

No, I'm sorry, as I don't maintain their drivers. Hardware-wise it should be possible, I believe. Every halfway decent chip has overlay support. Please contact the vendor of the corresponding driver.
Forum: support.Other 21 November 2021, 12:48
Replies: 248
Views: 40,037
Posted By Thomas Richter
The interface exists since release 2.x, but may...

The interface exists since release 2.x, but may be not very well debugged. Last changes were made in 3.1.0 where the functionality was debugged for the S3Virge chipset.



Note, however, that...
Forum: Nostalgia & memories 21 November 2021, 11:00
Replies: 800
Views: 69,649
Posted By Thomas Richter
That's a bit what I was afraid of. ...

That's a bit what I was afraid of.




The Amiga was designed to be a games console, yes, and thus depended on the 15kHz scan rates.
Forum: support.Other 21 November 2021, 10:17
Replies: 248
Views: 40,037
Posted By Thomas Richter
It's not only planned, it is already in since a...

It's not only planned, it is already in since a long time. On P96, this is called "PIP" "Picture in Picture", though it is actually an overlay. You find source code how to use it on supported cards...
Forum: Coders. Asm / Hardware 20 November 2021, 17:25
Replies: 23
Views: 1,365
Posted By Thomas Richter
Kick 1.x will not work with any processor with...

Kick 1.x will not work with any processor with caches that are "worth mentioning", i.e 68040 and up.
Forum: Nostalgia & memories 20 November 2021, 14:14
Replies: 800
Views: 69,649
Posted By Thomas Richter
A couple of annoying features of my A2000: The...

A couple of annoying features of my A2000: The proprietary RGB output connector - I'm not sure whether the PC style VGA connector was already an established standard, but if so, this would have...
Forum: Coders. Asm / Hardware 20 November 2021, 10:25
Replies: 23
Views: 1,365
Posted By Thomas Richter
No. To clear the caches, call "CacheClearU()", an...

No. To clear the caches, call "CacheClearU()", an exec function, which takes care of all processors and cache types. You only need to do this if you modify code, or load data as code. The typical...
Forum: Coders. General 18 November 2021, 20:33
Replies: 323
Views: 24,284
Posted By Thomas Richter
Actually, it depends on the environment and the...

Actually, it depends on the environment and the machine the code is executed on. For example, if adding two signed integers overflows, there is nothing the C standard guarantees. It is undefined...
Forum: Coders. General 18 November 2021, 19:08
Replies: 323
Views: 24,284
Posted By Thomas Richter
Sorry, but that seems to be the wrong approach -...

Sorry, but that seems to be the wrong approach - at least as long as you're still able to ask people from that age.



As long as you restrict yourself to a subset of the possibilities of the...
Forum: Coders. General 18 November 2021, 07:39
Replies: 323
Views: 24,284
Posted By Thomas Richter
And why is that an important target, in year...

And why is that an important target, in year 2021? Furthermore, why is this even the right forum, given that eab is on Amiga?
Forum: Coders. General 17 November 2021, 20:27
Replies: 323
Views: 24,284
Posted By Thomas Richter
How does that relate to the "speed"...

How does that relate to the "speed" argument?
Forum: Coders. General 17 November 2021, 14:19
Replies: 323
Views: 24,284
Posted By Thomas Richter
Does the speed argument even matter in 2021?...

Does the speed argument even matter in 2021? Today's machines are by at least two powers of magnitude faster than machines back then.
Forum: Coders. General 17 November 2021, 09:45
Replies: 323
Views: 24,284
Posted By Thomas Richter
As a reminder, it's 2021 now. Not 1983. ...

As a reminder, it's 2021 now. Not 1983.



Advice: Don't use this. It is outdated. We're now almost 40 years after the release of MS-DOS. The only advice you should give to authors is not to...
Forum: Coders. General 17 November 2021, 08:58
Replies: 323
Views: 24,284
Posted By Thomas Richter
Fixed hardware addresses and magic pointers I...

Fixed hardware addresses and magic pointers I would definitely not use for a new design. How do you know that your graphics hardware is accessible in this area? What if not? Thus, now your "Os"...
Forum: Nostalgia & memories 16 November 2021, 22:30
Replies: 800
Views: 69,649
Posted By Thomas Richter
You loose extreme colors, that's what I'm saying...

You loose extreme colors, that's what I'm saying all the time. It's a smaller color gamut. If you loose two bits, that 1024 colors that remain, not 300.
Forum: Nostalgia & memories 16 November 2021, 20:39
Replies: 800
Views: 69,649
Posted By Thomas Richter
It doesn't matter. Think about this. The...

It doesn't matter. Think about this. The transformation is reversible on the full domain. Hence, the points where it is not invertible on the restricted input are exactly those points in RGB space...
Forum: Coders. General 16 November 2021, 18:17
Replies: 323
Views: 24,284
Posted By Thomas Richter
Urgh. So we are back to screen poking? Why, just...

Urgh. So we are back to screen poking? Why, just why? What if you want to have memory in this region, and your graphics card memory does not fit into 64K?
Forum: Nostalgia & memories 16 November 2021, 18:12
Replies: 800
Views: 69,649
Posted By Thomas Richter
In the same way, one 6 bit adder, 3 5 bit adders,...

In the same way, one 6 bit adder, 3 5 bit adders, apparently.
Forum: Nostalgia & memories 16 November 2021, 18:11
Replies: 800
Views: 69,649
Posted By Thomas Richter
Which, again, does not matter. Think about it....

Which, again, does not matter. Think about it. You just create a different color gamut. What you miss if you clip in YUV space to a smaller range (8 bit instead of 9 bit) are extreme colors, namely...
Forum: Nostalgia & memories 16 November 2021, 15:32
Replies: 800
Views: 69,649
Posted By Thomas Richter
Let's look at the code: Y = 8 bit unsigned,...

Let's look at the code: Y = 8 bit unsigned, Cb,Cr: 9 bit signed. (8 bit plus sign bit)

Reconstruction of G = Y - ((Cb + Cr) >> 2)

This makes 9->10 bit adder, and a 9-bit adder if you want to...
Forum: Nostalgia & memories 16 November 2021, 15:17
Replies: 800
Views: 69,649
Posted By Thomas Richter
There are no rounding errors. This is a...

There are no rounding errors. This is a lossless(!) integer to integer transformation. You need precisely 0 fractional bits for this to work.
Forum: Nostalgia & memories 16 November 2021, 15:16
Replies: 800
Views: 69,649
Posted By Thomas Richter
Thanks for that. Indeed, agreed. We had this also...

Thanks for that. Indeed, agreed. We had this also tested in a separate thread, and given the amount of noise in the system, you already have trouble enough with the existing technology.
Forum: Nostalgia & memories 16 November 2021, 15:10
Replies: 800
Views: 69,649
Posted By Thomas Richter
Nothing is lost. Just to note that again: This is...

Nothing is lost. Just to note that again: This is a LOSSLESS transformation. For 8 bit RGB, you need 8 bit Y, 9 bit Cb and 9 bit Cr. (8 bit plus sign). Yes, really.
Forum: Coders. General 16 November 2021, 09:33
Replies: 323
Views: 24,284
Posted By Thomas Richter
That depends on the "memory model". ...

That depends on the "memory model".




"Amazing" as in "it hurts amazingly", then yes. It was a stupid design, and intel knew that. They used a completely different extension mechanism in...
Forum: Coders. General 16 November 2021, 09:10
Replies: 323
Views: 24,284
Posted By Thomas Richter
It depends. If you look at the code required for...

It depends. If you look at the code required for "far" pointers, it's ugly. A pointer is, depending on the "model", a collection of a base and an offset relative to it. I would not consider this an...
Forum: Coders. General 16 November 2021, 09:08
Replies: 323
Views: 24,284
Posted By Thomas Richter
You cannot just "import parts of a library"....

You cannot just "import parts of a library". Either a library is opened and used, or its not. If it is open, it exists entirely and completely.



Now, the functions you use are coming from dos...
Forum: Nostalgia & memories 16 November 2021, 08:31
Replies: 800
Views: 69,649
Posted By Thomas Richter
No digital silicon. Analog. Resistor ladders,...

No digital silicon. Analog. Resistor ladders, same stuff as used for the video DAC right now.



I don't propose to deal with them in silicon at all. This is all analog, and shifting a signal =...
Forum: Coders. General 15 November 2021, 20:25
Replies: 323
Views: 24,284
Posted By Thomas Richter
Unfortunately, it is. Or rather a historical...

Unfortunately, it is. Or rather a historical accident, where "char" was, originally, of course the character type of the machine it run on, but this type of interpretation became problematic for some...
Forum: Coders. General 15 November 2021, 18:13
Replies: 323
Views: 24,284
Posted By Thomas Richter
Unicode is an encoding, not a type. If you mean...

Unicode is an encoding, not a type. If you mean "wide characters", there is a wide character type wchar_t for encodings that require characters that are wider than char. "char" is not related to the...
Forum: Coders. General 15 November 2021, 14:27
Replies: 323
Views: 24,284
Posted By Thomas Richter
Except that a sane Os runs at the other end, and...

Except that a sane Os runs at the other end, and not MS-DOS. There is a command line, sure, but the command line works by a couple of different/advanced principles MS-DOS didn't have. And you have...
Forum: Coders. General 15 November 2021, 14:15
Replies: 323
Views: 24,284
Posted By Thomas Richter
It can perfectly be 9 bit, or 16 bit, or 32 bit,...

It can perfectly be 9 bit, or 16 bit, or 32 bit, or 36 bit. That's not a problem for the "C virtual machine" (an entirely hypothetical machine the authors of ISO C came up with).




It's 1....
Forum: Coders. General 14 November 2021, 23:32
Replies: 323
Views: 24,284
Posted By Thomas Richter
If you want to prove a concept, why start with an...

If you want to prove a concept, why start with an insane and obsolete concept? I'm sorry, I just don't get it.



No, it doesn't, that's exactly the point. Look at the code a C compiler has to...
Forum: Nostalgia & memories 14 November 2021, 23:06
Replies: 800
Views: 69,649
Posted By Thomas Richter
That depends on whether the text has the same...

That depends on whether the text has the same color as the background, obviously.





That depends a bit on the color system, and its clearly an approximation, but close enough to describe...
Forum: Nostalgia & memories 14 November 2021, 23:04
Replies: 800
Views: 69,649
Posted By Thomas Richter
Yes, I can. It's really quite trivial. void...

Yes, I can. It's really quite trivial.

void rct_pixel(rct_t r,rct_t g,rct_t b,rct_t* y, rct_t* cb, rct_t* cr)
{
*y = (rct_t) (r+2*g+b)>>2;
*cb = (rct_t) b-g;
*cr =...
Forum: Coders. General 14 November 2021, 16:02
Replies: 323
Views: 24,284
Posted By Thomas Richter
As a starter system, that's barely a good start....

As a starter system, that's barely a good start. It's an obsolete system. If you want to start something, start from something that follows a good technical design and that builds on state of the...
Forum: Coders. General 14 November 2021, 12:35
Replies: 323
Views: 24,284
Posted By Thomas Richter
Actually, that's far from "perfect" given the...

Actually, that's far from "perfect" given the demands on an Os today. For example, "GUI". Even the "bios" (actually UEFI) boot menu of computers nowadays come with a mouse-driven GUI, so falling...
Forum: Nostalgia & memories 14 November 2021, 12:13
Replies: 800
Views: 69,649
Posted By Thomas Richter
That is called a "soft interrupt", and exec has...

That is called a "soft interrupt", and exec has perfect support for it through the "Cause()" function. The CIA timers unfortunately don't use it, but - to give one better example - the P96 int2 and...
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