R800 information

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Van anonymous

incognito ergo sum (116)

afbeelding van anonymous

26-09-2004, 05:19

I am willing to discuss things more seriously and in more depth, but that seems to be impossible Sad
Funny how you say you are willing to discuss this, but can't come up with any arguments. Well, the accumulator one... but that's it... and it's not even a good one, because it's implied by the instruction set. It has no bearing on the actual design of the CPU.
Besides, IIRC at least one major RISC CPU had an accumulator.

Are you just that dumb, or are you trying to be funny?I'm just trying to be funny, but 6205 is a lot more RISC than Z80.
6502 has many different addressing modes, some of which incredibly complex.
It has no sign of a load-store architecture, as most instructions are of the read-modify-write kind.
Its register set is too small to be taken seriously, just 3 registers...

Everything about it shouts CISC!

You really should do more research, otherwise even more people will start thinking you're seriously lacking in the intelligence department...

Van idrougge

Resident (44)

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28-09-2004, 16:31

Are you just that dumb, or are you trying to be funny?I'm just trying to be funny, but 6205 is a lot more RISC than Z80.
6502 has many different addressing modes, some of which incredibly complex.

Consider this: The 6502 was produced to favour memory over internal registers, since this cuts costs and since memory was very fast back in the seventies (compared to the processor, that is). You could regard the zero page as a big register set. Now, addressing is much clearer, isn't it?

Its register set is too small to be taken seriously, just 3 registers...

The Z80 doesn't compare favourably here, since all its registers are special-purpose. The register layout of the Z80 is, no matter the amount of registers, far less RISC-like than the 6502, which has an accumulator and two index registers and nothing else. No LDIRs here.

Everything about it shouts CISC!

The uniform opcode size is a RISCy trait. Some would say that the instruction set is "reduced", too.

Van anonymous

incognito ergo sum (116)

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29-09-2004, 00:17

Consider this: The 6502 was produced to favour memory over internal registers, since this cuts costs and since memory was very fast back in the seventies (compared to the processor, that is). You could regard the zero page as a big register set. Now, addressing is much clearer, isn't it?
I know this, but they are not registers, they are RAM... So a RISC implementation would be impossible, unless you put the Zero page internal to the CPU and call it registers :/

The Z80 doesn't compare favourably here, since all its registers are special-purpose.
The 6502 registers are very limited in their use, and each have their own specialities. IMO the Z80 is much more orthogonal in this.

The register layout of the Z80 is, no matter the amount of registers, far less RISC-like than the 6502, which has an accumulator and two index registers and nothing else. No LDIRs here.
ARM has LDIR...

The uniform opcode size is a RISCy trait. Some would say that the instruction set is "reduced", too.
There's no uniform opcode size on 6502, neither is the instruction set 'reduced'. In fact, it's really big compared to the Z80!

Van jr

Champion (375)

afbeelding van jr

29-09-2004, 07:37

ARM has LDIR...

I'm curious - which ARM version is this and which command are you referring to? LDM/STM on an ARM is hardly the same as LDIR on Z80. As far as I know ARM does not have memory->memory copy/move commands at all.

Van ro

Scribe (4531)

afbeelding van ro

29-09-2004, 17:46

for ppl like me who don't know shit about risc, cisc, arm and all the goods:
let's look it up on the internet shall we Tongue

http://cse.stanford.edu/class/sophomore-college/projects-00/risc/whatis/index.html

http://www.hitequest.com/Kiss/risc_cisc.htm

http://www.heyrick.co.uk/assembler/index.html#03

Having read this I'm with Guyver here, I quess. (but then again, I'm a lousy reader and should have considered reading it again, and reading some more on the R800 stuff... oh well)

you might even wanna google with these parameters, interesting!

define:CISC

and

define:RISC

Van anonymous

incognito ergo sum (116)

afbeelding van anonymous

29-09-2004, 19:38

ARM has LDIR...
I'm curious - which ARM version is this and which command are you referring to? LDM/STM on an ARM is hardly the same as LDIR on Z80. As far as I know ARM does not have memory->memory copy/move commands at all.

You are right, it's not the same as on Z80. In fact, it's a lot more complex!
And ARM's SWP is a read-modify-write instruction, another CISC-like feature.

My point is: Just because a processor has a few CISC-like features, does not mean its architecture (and I don't mean Instruction Set) is CISC!

ARM has a lot of CISC features, but it's still a RISC CPU. The same counts for R800.

Van sjoerd

Hero (602)

afbeelding van sjoerd

30-09-2004, 14:50

Funny how you say you are willing to discuss this, but can't come up with any arguments.I haven't heard even one single argument from you either. I mean, "R800 is RISC, it's the design, the name and the fact that it was always presented as a RISC CPU." Uhm, oh.
design: only the implementation is somewhat 'risc-like'.
name: non-argument. that's just marketing.
presented as risc: non-argument. just marketing.

In short: risc is about the architecture, what the cpu looks like from the programmers' perspective. In my humble opinion of course.
Well, the accumulator one... but that's it... and it's not even a good one, because it's implied by the instruction set. It has no bearing on the actual design of the CPU.That's the point. The architecture is RISC or not, the implementation is not that important. (Since every modern CPU implementation uses the same design principles anyway). Btw: design is both architecture and implementation of course.
Everything about it [6502] shouts CISC!Yes, but more risc than Z80... The use of RAM instead of registers is just an implementation issue Wink
You really should do more research, otherwise even more people will start thinking you're seriously lacking in the intelligence department...If they will do some research they will notice I am right. If they don't and think I am "seriously lacking in the intelligence department," there isn't much I can do about it, can I? Maybe they can convince me why R800 is RISC...
If "you're stupid if you think R800 is not RISC" is an argument why R800 is RISC, then something went wrong here...

I think architecture is important (instruction set, register set and such), GuyveR800 thinks the implementation matters more to determine a CPU is RISC or not. Nice.

Ro: I could point you to a lot of Internet sites that support 'my' view. It wouldn't mean much of course, because for every view and opinion there's a hundred websites. Smile

Van anonymous

incognito ergo sum (116)

afbeelding van anonymous

30-09-2004, 18:30

Ah.. so you've reached the point where you have to start twisting my words and ignoring most of what is said.

This discussion is over...

As for websites supporting your view... There are also websites claiming no holocaust took place in WW2.

'nuff said.

Van ro

Scribe (4531)

afbeelding van ro

30-09-2004, 20:19

Well, for me being a total dipshit about R/C-ISC stuff (I only know the RISC game kicks ass, but that's some other story I suppose) I just had to do some quick research on the net (thaz what it's for, not?)

In my opinion; both are you are dead wrong and totally right on this issue. I don't know, neither do I care that much. It's interesting to see this *hot* discussion getting slightly out of hand again. It's funny seeing 2 ppl fight about what a procesor should be labeled at. Maybe some other clever mind can shed some light on this sub?

(oh, and don't even start flaming me guys, I take no site nor do I point any finger, start calling any of you a total no-no-whimp or what ever. I'm just as curious as the next idiot Smile )

cheers dudes!

Van sjoerd

Hero (602)

afbeelding van sjoerd

01-10-2004, 01:28

Ah.. so you've reached the point where you have to start twisting my words and ignoring most of what is said.No. ahh, well,... You're not even trying to see it from my point of view, are you? Smile
There are also websites claiming no holocaust took place in WW2.I already said: "It wouldn't mean much of course, because for every view and opinion there's a hundred websites."
Comparing "r800 is cisc" with "there was no holocaust" is pretty pathetic. It would be nice if you wouldn't do that. What are you trying to say here? Since R800==CISC...
'nuff said.No, too much. There was no need for personal attacks.

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