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Forum: Coders. Asm / Hardware 26 November 2020, 15:45
Replies: 22
Views: 636
Posted By roondar
Yeah, clearing is fairly fast operation to begin...

Yeah, clearing is fairly fast operation to begin with so there's really not that much to optimise.

Just to be complete then: the above code is only partly optimised. A pure assembly version could...
Forum: Coders. Asm / Hardware 26 November 2020, 14:28
Replies: 22
Views: 636
Posted By roondar
It may be possible to optimise the above code...

It may be possible to optimise the above code further, but that depends on what the compiler does with it. If the compiler keeps the code mostly as is when converting, the inner loop is likely fairly...
Forum: Coders. Asm / Hardware 25 November 2020, 15:17
Replies: 22
Views: 636
Posted By roondar
Oh, I see what you mean. I thought you wanted...

Oh, I see what you mean. I thought you wanted both CPU & Blitter to just clear. It does change a bit if you want one to clear and the other to draw. Anyway, I fully agree it's best to flesh out your...
Forum: Coders. Asm / Hardware 25 November 2020, 14:45
Replies: 22
Views: 636
Posted By roondar
I feel that I might be missing something here,...

I feel that I might be missing something here, because I'm not sure why that would be. If you run both CPU and Blitter at the same time, you'll should get the benefit irrespective of whether you do...
Forum: Coders. Asm / Hardware 25 November 2020, 14:40
Replies: 22
Views: 636
Posted By roondar
You could instead clear the top of the bitmap...

You could instead clear the top of the bitmap with the Blitter and bottom with the CPU (or vice versa) - no problems with interleaved that way ;)
Forum: Coders. Asm / Hardware 25 November 2020, 14:20
Replies: 22
Views: 636
Posted By roondar
Indeed, this is one of the blits where it doesn't...

Indeed, this is one of the blits where it doesn't matter: Blitter clear won't be faster using BLITHOG and the CPU won't be halted either because of the Blitter idle cycles during clearing.

It can...
Forum: New to Emulation or Amiga scene 25 November 2020, 13:34
Replies: 25
Views: 770
Posted By roondar
I've found that 100Hz also helps a whole lot with...

I've found that 100Hz also helps a whole lot with smooth scrolling, if your monitor supports it.
Forum: Coders. Asm / Hardware 25 November 2020, 13:19
Replies: 22
Views: 636
Posted By roondar
Waiting with BLITHOG on is normally more...

Waiting with BLITHOG on is normally more efficient than waiting without it for certain blits (compared to waiting with BLITHOG off). However, it's not always faster and causes some issues with...
Forum: Coders. Asm / Hardware 22 November 2020, 13:25
Replies: 3
Views: 577
Posted By roondar
One option I once experimented with is doing...

One option I once experimented with is doing multiple collision checks per frame so that you can guarantee that the objects motion is accurately captured using smaller bounding boxes.

Essentially,...
Forum: Coders. Asm / Hardware 16 November 2020, 18:42
Replies: 44
Views: 2,177
Posted By roondar
Thanks, both of those might be a good options :)

Thanks, both of those might be a good options :)
Forum: Coders. Asm / Hardware 16 November 2020, 17:25
Replies: 44
Views: 2,177
Posted By roondar
Now I've been looking for a random number...

Now I've been looking for a random number algorithm generator as well and it looks like something like xorshift would be good enough for my purpose. Assuming I'd use xorshift, what would be good...
Forum: Retrogaming General Discussion 05 November 2020, 18:31
Replies: 35
Views: 1,900
Posted By roondar
Ehhmm.. No comment, never actually seen or...

Ehhmm.. No comment, never actually seen or touched one :D
Forum: Retrogaming General Discussion 05 November 2020, 18:17
Replies: 35
Views: 1,900
Posted By roondar
Oh, absolutely! But then I do tend to think...

Oh, absolutely!
But then I do tend to think there's value in just about every system ever released, even if I have my own favourites :)
Forum: Coders. C/C++ 05 November 2020, 13:05
Replies: 8
Views: 543
Posted By roondar
That's not how I read his post/code (I took it to...

That's not how I read his post/code (I took it to be that myBitplane would be what is shown on the screen) as he never mentions copying it anywhere and it makes more sense that way, but perhaps...
Forum: Coders. C/C++ 05 November 2020, 12:48
Replies: 8
Views: 543
Posted By roondar
It should be pointed out that your example does...

It should be pointed out that your example does copy the data. It just uses a function rather than manually doing it. I agree this is the better way, but it's still making a copy ;)
Forum: Coders. C/C++ 05 November 2020, 11:45
Replies: 8
Views: 543
Posted By roondar
A yes, we do ;) @OP I thought of one more...

A yes, we do ;)

@OP
I thought of one more thing. In addition to all other things, be aware that you're drawing two bytes per call of the loop, but move forward by only one position. If you want...
Forum: Coders. C/C++ 05 November 2020, 11:32
Replies: 8
Views: 543
Posted By roondar
The Amiga is a big-endian machine, the high byte...

The Amiga is a big-endian machine, the high byte comes first in memory and is followed by the low byte. This is true for both code and GFX data.

So in your code the address order should be...
Forum: Coders. C/C++ 02 November 2020, 15:59
Replies: 44
Views: 1,731
Posted By roondar
Oh no.... I forgot the EA :banghead Ok, I'll...

Oh no.... I forgot the EA :banghead
Ok, I'll hang up my coding hat and leave in disgrace now :laughing
Forum: Coders. General 02 November 2020, 15:14
Replies: 20
Views: 2,741
Posted By roondar
Ah, I did read the OP but missed that bit. Makes...

Ah, I did read the OP but missed that bit. Makes perfect sense!
Forum: Coders. General 02 November 2020, 15:05
Replies: 20
Views: 2,741
Posted By roondar
You know, I do have one question: how do you deal...

You know, I do have one question: how do you deal with the layer's individual motion? Vertical is probably quite easy (just use different offsets for the bitplane pointers). But horizontally you only...
Forum: Coders. C/C++ 02 November 2020, 15:02
Replies: 44
Views: 1,731
Posted By roondar
You are quite correct that MULU doesn't work with...

You are quite correct that MULU doesn't work with words as a source, but the result of MULU is a longword. So the use of longwords is probably correct for a general purpose multiply. If the result is...
Forum: Coders. C/C++ 02 November 2020, 14:33
Replies: 44
Views: 1,731
Posted By roondar
Interesting, I got 38+2n in my source: ...

Interesting, I got 38+2n in my source:
MULS,MULU - The multiply algorithm requires 38+2n clocks where n is defined as:
MULU: n = the number of ones in the <ea>
MULS: n = concatanate the...
Forum: Coders. C/C++ 02 November 2020, 11:44
Replies: 44
Views: 1,731
Posted By roondar
A mulu #100,d0 would take 44 cycles (mulu costs...

A mulu #100,d0 would take 44 cycles (mulu costs 38 cycles + 2 cycles per 1 in the bit pattern of the EA).

I'd guess that *100 would be *64+*32+*4. Just looking at the shifts (plus the two adds for...
Forum: Coders. C/C++ 02 November 2020, 11:21
Replies: 44
Views: 1,731
Posted By roondar
You know, I have no idea how to get C/C++ to use...

You know, I have no idea how to get C/C++ to use bset. The rest ought to be possible, but that one seems tricky to me. Then again, I've not done any serious C coding in years so I'm not the best bet...
Forum: Coders. C/C++ 01 November 2020, 18:50
Replies: 10
Views: 538
Posted By roondar
As far as I've been able to tell, using longwords...

As far as I've been able to tell, using longwords is faster than using words for 32 bit writes, even on the A500. It doesn't appear to matter if the code is in chip memory or fast memory, though if...
Forum: Coders. General 01 November 2020, 13:31
Replies: 20
Views: 2,741
Posted By roondar
Cool! Congrats on the release :)

Cool! Congrats on the release :)
Forum: support.WinUAE 01 November 2020, 13:30
Replies: 36
Views: 2,065
Posted By roondar
If you don't like WinUAE, there are some...

If you don't like WinUAE, there are some alternatives which might be easier to use. There's FS-UAE which has a simpler interface. And there's also Amiga forever, which is basically "click and play",...
Forum: Retrogaming General Discussion 01 November 2020, 13:26
Replies: 35
Views: 1,900
Posted By roondar
I do apologize for missing that, this is not how...

I do apologize for missing that, this is not how I read "I find the average nes game to be much more accessible and easier...". I probably also misread it because of the post you replied to, which...
Forum: Retrogaming General Discussion 31 October 2020, 23:57
Replies: 35
Views: 1,900
Posted By roondar
To be fair here (assuming you mean Super Mario...

To be fair here (assuming you mean Super Mario Brothers), that is in no way an "average" game. It's one of the best games of all times and consistently rated as such. The kind of game you don't see...
Forum: Retrogaming General Discussion 30 October 2020, 18:20
Replies: 35
Views: 1,900
Posted By roondar
That'd certainly be an interesting ad to see! ...

That'd certainly be an interesting ad to see!
Wish they had done it (and for more than just that game).

Then again, I didn't even know there was a PAL version of Castlevania - I thought it was...
Forum: Coders. Asm / Hardware 30 October 2020, 18:05
Replies: 2
Views: 424
Posted By roondar
Thanks! I had just finished writing a tiny test...

Thanks!
I had just finished writing a tiny test program to see for myself and that is indeed what it does :)
Forum: Retrogaming General Discussion 30 October 2020, 17:44
Replies: 35
Views: 1,900
Posted By roondar
Metal Slug is fun to post about because it's so...

Metal Slug is fun to post about because it's so far out of reach that you have to really dig deep in the box of tricks to even try to get close (at least for me).

And yeah, Castlevania should...
Forum: Retrogaming General Discussion 30 October 2020, 17:18
Replies: 35
Views: 1,900
Posted By roondar
Ah, I have apparently learned to try and stop...

Ah, I have apparently learned to try and stop some lines of discussion earlier since then :D

Roondar's brain pseudo code with bugfix:

IF (discussion_topic == unlikely_to_lead_anywhere) &&...
Forum: Coders. Asm / Hardware 30 October 2020, 17:08
Replies: 2
Views: 424
Posted By roondar
68020+ scale factor behaviour?

This is an offshoot of the setting a pixel thread. There was a tiny bit of discussion about compilers and how they selected words vs longwords for operations and chb correctly pointed out that the...
Forum: Coders. C/C++ 30 October 2020, 16:53
Replies: 44
Views: 1,731
Posted By roondar
DOH! Of course it can't... Oh well, I'm only...

DOH! Of course it can't... Oh well, I'm only human - I'm allowed to make silly mistakes :laughing
Forum: Retrogaming General Discussion 30 October 2020, 16:51
Replies: 35
Views: 1,900
Posted By roondar
I guess it's best we'll agree to disagree here,...

I guess it's best we'll agree to disagree here, saves us both quite a few posts (because I don't agree with that statement, while respecting why you might see it differently) :agree
Forum: Coders. C/C++ 30 October 2020, 16:14
Replies: 44
Views: 1,731
Posted By roondar
Interesting.. The compiler chose to use longwords...

Interesting.. The compiler chose to use longwords for the X value and index, even though the code only needs words. It doesn't really matter that much (it's only 8 cycles slower, not really a big...
Forum: Coders. C/C++ 30 October 2020, 16:00
Replies: 44
Views: 1,731
Posted By roondar
That's certainly an improvement. But now that I'm...

That's certainly an improvement. But now that I'm in the optimising mood, I'd also suggest creating a constant for DISPLAY_WIDTH_IN_WORD*DISPLAY_DEPTH for an easy small optimisation (multiplying...
Forum: Retrogaming General Discussion 30 October 2020, 15:56
Replies: 35
Views: 1,900
Posted By roondar
It wasn't very clear from the rest of the text so...

It wasn't very clear from the rest of the text so just to be clear: I'm only talking about action games in this post :)

Many of the 8-bit NES games were great fun to play. Not sure I agree that...
Forum: Coders. C/C++ 30 October 2020, 15:37
Replies: 44
Views: 1,731
Posted By roondar
Table lookup is usually something like ;...

Table lookup is usually something like

; assumes table in A0
add.w d0,d0 ; this can be optimised by always doubling the X-coordinate.
move.w 0(a0,d0.w),d1

Total = 4 cycles for the add and 14...
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