@kolla

Developer: "Ahh. How about move?"

Apollo: "Well, we don't get much call for it around here, sir."

Developer: "Not much ca--It's the single most popular operation in the world!"

Apollo: "Not 'round here, sir."

Developer: "and what IS the most popular operation 'round hyah?"

Apollo: "Miniterm, sir."

Developer: "IS it?"

Apollo: "Oh, yes, it's staggeringly popular in this manor, squire."

Developer: "Is it?"

Apollo: "It's our number one best seller, sir!"

Developer: "I see. Uuh... Miniterm, eh?"

Apollo: "Right, sir."

Developer: "All right. Okay. 'Have you got any documenration?' he asked, expecting the answer 'no'."

Apollo: "I'll have a look, sir... nnnnnnnnnnnnnnnno."

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Doing stupid things for fun...

@Karlos

Quote:

Karlos wrote: Maybe one for Gunnar before the angry mob get him banned... I was curious about the 64-bit extensions in the 68080 and found the following developer documentation: http://www.apollo-core.com/features.html#refins It's a bit confusing. I naively assumed that there would be 64-bit integer versions of the common arithmetic and logical operations

Why?

@bhabbott

Why what? If you mean why did I assume there would be 64 bit variations of common operations? The claim has been made that the 68080 is 64-bit. It's generally the case when architectures expand register widths that they get new instruction variations to support the new width.

The documentation is just a bit poor and needs a refresh. It looks like it's been taken directly from existing 68K manuals. Many operations still say "byte, word, long" for the size attribute but if you glance into the body description it will say quad also tacked on somewhere. Equally there are example three operand variants with no documentation.

Last edited by Karlos on 28-Nov-2022 at 09:37 AM.

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Doing stupid things for fun...

@kolla

Where's the AROS 64-bit port for AC68080?

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Amiga 1200 (rev 1D1, KS 3.2, PiStorm32/RPi CM4/Emu68)
Amiga 500 (rev 6A, ECS, KS 3.2, PiStorm/RPi 4B/Emu68)
Ryzen 9 7950X, DDR5-6000 64 GB RAM, GeForce RTX 4080 16 GB

@Karlos

Quote:

Karlos wrote: @bhabbott Why what? If you mean why did I assume there would be 64 bit variations of common operations? The claim has been made that the 68080 is 64-bit.

Where?

@bhabbott

https://amigaworld.net/modules/newbb/viewtopic.php?topic_id=44581&forum=15&start=520&viewmode=flat&order=0

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SAM440EP-FLEX @ 733 Mhz, AmigaOS 4.1 Update 1

@bhabbott

One of the long rambling threads with the (probably fake) Gunnar.

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Doing stupid things for fun...

Gunnar is always fake.

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B5D6A1D019D5D45BCC56F4782AC220D8B3E2A6CC

Quote:

Massi wrote: @bhabbott https://amigaworld.net/modules/newbb/viewtopic.php?topic_id=44581&forum=15&start=520&viewmode=flat&order=0

Finally we get to the heart of the matter...

Quote:

68080 PROGRAMMING MODEL 16 64-Bit Address registers (A0-A15) 8 64-Bit General Purpose Data registers (D0-D7) 8 64-Bit FPU registers (Fp0-Fp7) 24 64-Bit General Purpose Data registers (E0-E23) which can be used by both ALU and FPU. 32 Data Registers (D0-D7, E0-E23) These registers are for bit and bit field (1 - 32 bits), byte (8 bits), word (16 bits), long-word (32 bits), and quad-word (64 bits) operations. D0-D7 can also be used as index registers in EA calculation. 32 FPU Registers (Fp0-Fp7,E0-E23) The FPU has access to 32 work registers. In addition to this FPU instructions can also use register also use the 8 Dn Register as source. Therefore the FPU has 32 registers it can update with calculation, and 40 registers it can use as source. 16 Address Registers (A0-A15) These registers can be used as software stack pointers, index registers, or base address registers. The base address registers can be used for [b]word and long-word operations.

I presume nobody disputes this model, so it comes down to Karlos's 'naive' assumption that there would be "64-bit integer versions of the common arithmetic and logical operations". The fact that these imaginary instructions are not documented anywhere apparently wasn't a big enough clue, nor how this large number of extra instructions would be shoehorned into the opcode map.

Karlos's excuse for his 'naivety' is that "It's generally the case when architectures expand register widths that they get new instruction variations to support the new width", which the 68080 did get with AMMX. But Karlos was expecting more than just some new 64 bit instructions - he thought the 'common' 32 bit ones would get a 64 bit variant too - even though this was not the case for CPUs with similar functionality in the past.

From the Intel Pentium MMX to Pentium IV, AMD K6 to K6 III and Athon XP etc., the 'common' instructions remained 32 bit. Other processor lines that increased the register width of 'common' instructions typically switched to a whole new ISA (eg. 8085 -> 8086, Z80 -> Z8000, 6809 -> 68000). 68k remained 32 bit throughout its life, with only a few 64 bit instructions added in the 68020 (and then some taken away again in the 68060).

Perhaps Karlos was thinking of x86 -> x64, but even that isn't quite true. In order to run 16 bit code the CPU has to be switched into 'real' mode, and then 64 bit instructions don't work, while some 'common' 32 bit instructions don't work in 64 bit mode. Clearly this method won't work for a drop-in CPU replacement used with an existing OS (i.e the Amiga). Anyway the 68080 is far different from x86, so assuming it will follow the same development path doesn't seem wise.

You can't reasonably expect supposed 'undocumented' instructions to exist just because you think they should. Not mentioning imaginary instructions is not 'poor' documentation, it's correct documentation. The actual 68080 64 bit instructions are documented.

Last edited by bhabbott on 29-Nov-2022 at 11:48 PM.
Last edited by bhabbott on 29-Nov-2022 at 11:46 PM.

@bhabbott

Quote:

I presume nobody disputes this model, so it comes down to Karlos's 'naive' assumption that there would be "64-bit integer versions of the common arithmetic and logical operations". The fact that these imaginary instructions are not documented anywhere apparently wasn't a big enough clue, nor how this large number of extra instructions would be shoehorned into the opcode map.

Shoehorned? Have a look at the existing opcode layout and acquaint yourself with the size field for common integer operations. It's a 2-bit field, 00: byte, 01: word, 10: long. Unless it's reserved for something else, 11 could be used to indicate a 64-bit integer size.

I said my assumption was naive, but it wasn't completely stupid. Moreover it is mentioned in a few of the common instructions documented for the 68080 that "quad" is a supported operand size, but it's rather hit and miss, which is why I asked in the first place.

Last edited by Karlos on 30-Nov-2022 at 06:18 AM.
Last edited by Karlos on 30-Nov-2022 at 05:53 AM.

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Doing stupid things for fun...

@Karlos
@kolla

I have never had the feeling that the user Gunnar is a fake.

What kind of clues do you have to support your statements ?

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SAM440EP-FLEX @ 733 Mhz, AmigaOS 4.1 Update 1

@Massi

The inability to answer questions like the one in this thread, despite being the architect of the system.

Last edited by Karlos on 30-Nov-2022 at 05:57 AM.

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Doing stupid things for fun...

@Karlos

OK.

But you created this thread the exact same day he announced he was going to be busy for A37 (and after that he disappeared).

Maybe only a coincidence that he didn' t respond to your questions (so far).

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SAM440EP-FLEX @ 733 Mhz, AmigaOS 4.1 Update 1

@Massi

Sure, but I didn't try to press for an answer until afterwards. As it was "Gunnar" was posting loads (in a lot of busy threads) right up to the eve of the event, then fell silent. This thread itself was broken out of one of those because he advised me to "read the docs*, when I asked. So I did. The rest is here.

Last edited by Karlos on 30-Nov-2022 at 09:29 AM.
Last edited by Karlos on 30-Nov-2022 at 09:28 AM.

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Doing stupid things for fun...

@bhabbott

You know, they say that if you type my name in bold five times in a single post, I materialise behind you ...

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Doing stupid things for fun...

@Massi

Quote:

Massi wrote: @Karlos @kolla I have never had the feeling that the user Gunnar is a fake.

No, I agree with you on that. My tongue-in-cheek comment was more about “faking it” being a fairly good description of his modus operandi - pretending to have something he doesn’t… at least not yet… and then strive to get there, manage it half way, call it close enough, and jump on the next thing.

Last edited by kolla on 30-Nov-2022 at 02:12 PM.

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B5D6A1D019D5D45BCC56F4782AC220D8B3E2A6CC

@Karlos

Quote:

The inability to answer questions like the one in this thread, despite being the architect of the system.

That is more like a confirmation of his identity.

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B5D6A1D019D5D45BCC56F4782AC220D8B3E2A6CC

@Karlos

Quote:

You know, they say that if you type my name in bold five times in a single post, I materialise behind you ...

Brandishing industrial lubricant?

So anyway, about those there 64 bit operations. What's the craic? Does anyone actually know?

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Doing stupid things for fun...

@Karlos

It seems your questions fall on deaf ears Geoff!