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Forum: Coders. General Today, 12:21
Replies: 304
Views: 19,444
Posted By Bruce Abbott
This thread is supposed to be about division on...

This thread is supposed to be about division on 68020/030 only, but discussing differences between them other CPUs is not totally out of place. Also the OP was interested in performance on 'real...
Forum: Coders. General Yesterday, 09:24
Replies: 304
Views: 19,444
Posted By Bruce Abbott
The actual write to ChipRAM must occur at the bus...

The actual write to ChipRAM must occur at the bus speed of 560ns between CPU slots, so writing a large block of data cannot be done any faster. The question is can a fast CPU use some of that time to...
Forum: Coders. General Yesterday, 08:42
Replies: 304
Views: 19,444
Posted By Bruce Abbott
Yes, it still takes only 28 seconds or 28 cycles...

Yes, it still takes only 28 seconds or 28 cycles per loop, which means those 10 extra instructions are executing out of cache (using only 2 clocks per instruction) while the external bus is...
Forum: Retrogaming General Discussion Yesterday, 01:17
Replies: 26
Views: 1,252
Posted By Bruce Abbott
I noticed the transition too, but was less...

I noticed the transition too, but was less impressed. The captures were often too 'perfect', missing nice effects of a CRT such as higher contrast and rounding of the pixels. On the Amiga it wasn't...
Forum: Coders. General Yesterday, 00:01
Replies: 304
Views: 19,444
Posted By Bruce Abbott
Here's a little puzzle for you. The following...

Here's a little puzzle for you. The following code takes 28 seconds to execute on my A1200 with 50MHz 68030 (Blizzard 1230-IV), equating to ~28 clock cycles per inner loop. Without the move.l ...
Forum: Coders. General 10 June 2021, 11:49
Replies: 304
Views: 19,444
Posted By Bruce Abbott
Speed appears to be identical to your earlier...

Speed appears to be identical to your earlier code. Doesn't look like we are going to squeeze any more blood out of this stone.

However the file size of your version is significantly smaller that...
Forum: Hardware mods 09 June 2021, 04:27
Replies: 23
Views: 2,386
Posted By Bruce Abbott
And I have a few that need to be used, so... ...

And I have a few that need to be used, so...

Right now the easiest way to secure Amiga custom chips is to just buy an old Amiga, so if that is all you want then there is no urgency to develop...
Forum: Amiga scene 09 June 2021, 02:02
Replies: 31
Views: 6,152
Posted By Bruce Abbott
I'm imagining something a lot more unique and...

I'm imagining something a lot more unique and original than the subject of this thread.
Forum: Coders. General 08 June 2021, 01:49
Replies: 304
Views: 19,444
Posted By Bruce Abbott
I presume so, but testing in FastRAM revealed...

I presume so, but testing in FastRAM revealed negligible difference between data cache on and off, perhaps because in this program the data spends most of its time in registers.

Even if the data...
Forum: Coders. General 07 June 2021, 17:06
Replies: 304
Views: 19,444
Posted By Bruce Abbott
Since this thread was originally supposed to be...

Since this thread was originally supposed to be about optimizing 32 bit division (and because I am sick of seeing 300 digits of pi on my screen) I decided that for initial comparisons I would measure...
Forum: support.Hardware 06 June 2021, 10:25
Replies: 5
Views: 266
Posted By Bruce Abbott
It has to be exactly the right one - so if you...

It has to be exactly the right one - so if you find one grab it! Hard to believe that the correct spares would still be available after all these years.
Forum: Amiga scene 06 June 2021, 10:19
Replies: 15
Views: 985
Posted By Bruce Abbott
More traditional - like that 'button' on your...

More traditional - like that 'button' on your prototype? ;)
Forum: News 06 June 2021, 10:11
Replies: 652
Views: 64,053
Posted By Bruce Abbott
Can you tell us more about this?

Can you tell us more about this?
Forum: support.Hardware 05 June 2021, 12:30
Replies: 5
Views: 266
Posted By Bruce Abbott
The 'pop' is probably an arc-over in the EHT...

The 'pop' is probably an arc-over in the EHT circuit, perhaps inside the transformer but it could be somewhere else. The screen expands because when the EHT voltage drops the electron beam is...
Forum: Coders. General 05 June 2021, 11:50
Replies: 304
Views: 19,444
Posted By Bruce Abbott
After fixing a few syntax issues (same ones in...

After fixing a few syntax issues (same ones in litwr's code) it assembled without errors. On running the sign-on message was corrupted, but after that it seemed to work OK.

Only one problem, it...
Forum: Coders. General 05 June 2021, 11:39
Replies: 35
Views: 1,057
Posted By Bruce Abbott
Please tell us more about this problem...

Please tell us more about this problem audio.device has on 68030.
Forum: Coders. General 05 June 2021, 11:22
Replies: 9
Views: 485
Posted By Bruce Abbott
I haven't done any coding in Blitz or AMOS...

I haven't done any coding in Blitz or AMOS (prefer assembler for the control and efficiency it provides) but if these compilers can create structures and call system library functions then they...
Forum: Amiga scene 05 June 2021, 09:54
Replies: 15
Views: 985
Posted By Bruce Abbott
What a fantastic idea! Let's makes games which...

What a fantastic idea! Let's makes games which only work on a custom-made controller that you can't buy and probably doesn't work.

Having more buttons makes them worse, not better. It took me...
Forum: Coders. General 05 June 2021, 00:33
Replies: 35
Views: 1,057
Posted By Bruce Abbott
That's not the only thing that broke with 68060,...

That's not the only thing that broke with 68060, which BTW no real Amiga ever had so it's not the fault of the OS or hardware if it doesn't work with a 68060.

That's a pity, but since the...
Forum: Coders. General 04 June 2021, 12:20
Replies: 35
Views: 1,057
Posted By Bruce Abbott
You know what's really a shame? Nobody produced a...

You know what's really a shame? Nobody produced a cartridge slot for the Amiga.

It wouldn't have been hard. The A1000, A2000 and A500 all have a nice expansion bus connector. There's plenty of...
Forum: Amiga scene 04 June 2021, 11:44
Replies: 29
Views: 1,509
Posted By Bruce Abbott
Syntrax expressed an interest in running QNX on...

Syntrax expressed an interest in running QNX on Amiga hardware. Syntrax asked if the code for it has been 'leaked'. What other conclusion was I to draw?
Forum: Amiga scene 04 June 2021, 01:45
Replies: 29
Views: 1,509
Posted By Bruce Abbott
Perhaps because of this? Strange that...

Perhaps because of this?

Strange that somebody would have that attitude towards Amiga OS, then suggest using 'leaked' QNX code.

Oh, and "BSD is bloated so that's no alternative".
Forum: Coders. General 03 June 2021, 15:00
Replies: 304
Views: 19,444
Posted By Bruce Abbott
Thanks, I will wait until you join all the...

Thanks, I will wait until you join all the changes and produce full working code.

I got litwr's code to assemble with ProAsm, which was quite a lot of work. It seems to run OK so I think I got it...
Forum: Amiga scene 03 June 2021, 14:46
Replies: 29
Views: 1,509
Posted By Bruce Abbott
You said Warp 1260 and Vampire are 'modern'...

You said Warp 1260 and Vampire are 'modern' hardware, but they aren't. The Vampire uses an old FPGA that doesn't have a dedicated CPU core. A modern FPGA could potentially be much faster - if it...
Forum: Amiga scene 03 June 2021, 13:34
Replies: 29
Views: 1,509
Posted By Bruce Abbott
Even Linux is considered 'exotic' by mainstream...

Even Linux is considered 'exotic' by mainstream developers today.

Today I tried to watch some episodes of my favorite TV programs, which are streamed via TVNZ On-Demand. All I need to view them...
Forum: Coders. General 03 June 2021, 12:13
Replies: 304
Views: 19,444
Posted By Bruce Abbott
This is not the full code. Can you post the...

This is not the full code. Can you post the complete working source code?
Forum: Amiga scene 03 June 2021, 00:21
Replies: 29
Views: 1,509
Posted By Bruce Abbott
Which capabilities, and why are they welcome? ...

Which capabilities, and why are they welcome?

QNX is 'perfect' for the Amiga, even though it doesn't have any part of its API? Not for me it wouldn't be. It would be useless.

At risk of what?...
Forum: Coders. General 30 May 2021, 00:28
Replies: 304
Views: 19,444
Posted By Bruce Abbott
As you say he was 'practically begging for it'...

As you say he was 'practically begging for it' but I would have thought we were adult enough to handle it. If he got banned I guess it must be for something other than his (visible) posts.

Anyway,...
Forum: Amiga scene 30 May 2021, 00:09
Replies: 98
Views: 7,266
Posted By Bruce Abbott
App stores? Steam? Hell no! One reason I still...

App stores? Steam? Hell no! One reason I still use an Amiga is to keep away from that crap.

The old methods of software distribution are fine. I love it that new games are being produced on...
Forum: Amiga scene 29 May 2021, 07:21
Replies: 98
Views: 7,266
Posted By Bruce Abbott
I feel so old and ignorant of the modern world -...

I feel so old and ignorant of the modern world - I have no idea what you are you are talking about.
Forum: Amiga scene 27 May 2021, 06:04
Replies: 493
Views: 38,135
Posted By Bruce Abbott
Thanks for that, I didn't know that magazine...

Thanks for that, I didn't know that magazine existed until today.

I found another advert in the Dec 1988 issue of ACAR. It offered the A2000 without monitor for $1995, and the A500 without...
Forum: support.Hardware 25 May 2021, 07:30
Replies: 4
Views: 250
Posted By Bruce Abbott
I haven't dealt with those particular eBay...

I haven't dealt with those particular eBay vendors, but my general experience has been:-

1. Never buy from a vendor with less than 99% positive feedback.

2. "New, good quality" means "used,...
Forum: Amiga scene 25 May 2021, 05:46
Replies: 1
Views: 375
Posted By Bruce Abbott
It's not such a simple question, because it...

It's not such a simple question, because it depends on several factors that vary depending on the particular machine.

On a standard 16 bit Amiga (A1000/500/600/2000) the ROM and RAM are both 16...
Forum: Coders. General 24 May 2021, 09:39
Replies: 304
Views: 19,444
Posted By Bruce Abbott
Magic numbers are less readable in general. What...

Magic numbers are less readable in general. What is bit #5? The code above provides no clue. To fix that you equate the bit number to a symbolic name, and then the fun starts.

For example, the...
Forum: Amiga scene 23 May 2021, 08:01
Replies: 493
Views: 38,135
Posted By Bruce Abbott
Unfortunately I couldn't find any contemporary...

Unfortunately I couldn't find any contemporary pricing for the Amiga 2000 in Australia, so I guess we will have to accept your claim that they were 'overpriced'.

My failure to find any Commodore...
Forum: Coders. General 23 May 2021, 04:07
Replies: 304
Views: 19,444
Posted By Bruce Abbott
This isn't a 'good' benchmark anyway, if you want...

This isn't a 'good' benchmark anyway, if you want something that gauges real-world performance. It's only real use is to show how an algorithm can be implemented on various retro computers. To this...
Forum: Coders. General 21 May 2021, 07:53
Replies: 304
Views: 19,444
Posted By Bruce Abbott
I think it is a reasonable limit, especially...

I think it is a reasonable limit, especially since some platforms targeted have 8 bit CPUs and less than 64k RAM.

As a benchmark this 'pi-spigot' is pretty silly, but then so are most synthetic...
Forum: Coders. General 21 May 2021, 04:47
Replies: 304
Views: 19,444
Posted By Bruce Abbott
Except that it isn't precisely long - it's a...

Except that it isn't precisely long - it's a signed byte extended to long - despite what the 68000 programmer's manual may say about it.
Forum: Amiga scene 21 May 2021, 04:22
Replies: 493
Views: 38,135
Posted By Bruce Abbott
Let's be honest - if all you wanted to do was run...

Let's be honest - if all you wanted to do was run "spreadsheets, word processing and the like" a PC was the obvious choice, and having a slow phosphor green screen with (at best) 1 bitplane graphics...
Forum: Coders. General 20 May 2021, 08:31
Replies: 304
Views: 19,444
Posted By Bruce Abbott
I think litwr wants fastest and smallest, so it's...

I think litwr wants fastest and smallest, so it's a bit tricky. Is a 5% speedup worthwhile if it adds 4 bytes to the file size?

On litwr's benchmark site...
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