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Author Topic: Does eight bit computing excite you?  (Read 9168 times)

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Re: Does eight bit computing excite you?
« on: February 26, 2009, 02:19:30 PM »
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Speelgoedmannetje wrote:

I just don't want x86 (or those 64 bits derivatives)


What exactly is wrong with the x86 and x86-64? I downloaded the manuals from intel last year and read through them... these are nice chips!

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Re: Does eight bit computing excite you?
« Reply #1 on: February 26, 2009, 07:41:35 PM »
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Speelgoedmannetje wrote:
I'm sorry if I have to be a bit vague here (it's quite a couple of years ago), but I recall there was something about this cpu design that forces you to juggle alot with registers and memory allocation (when programming in assembly).


Yeah, the x86 ISA is a bit weird, it's rather RISC like in a weird CISC way :crazy: The hardest detail is that the Opcodes and Addressing modes are not always orthogonal, as we are used to in the 68k... and there is the issue of only 8 registers, some instructions have certain register requirements too... which is a bit of a pain, but the SIMD, MMU and cache control is all very nice and lets face it only very rarely does one ever go to ASM now...

The x86-64 ISA has been nicely cleaned up, plus it has 16 general purpose regs like we are used to with our 68ks :-D (actually better than the 68k since there is no Address/Data separation) Probably the most difficult thing for a 68k coder on the x86-64 CPU is the lack of addressing modes... but all modern CPUs avoid complex addressing due to their getting in the way of high performance.

Though if you really want to suffer with asm in 2009... the ARM is really simple and very nice :-)

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Re: Does eight bit computing excite you?
« Reply #2 on: February 28, 2009, 04:39:51 PM »
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Speelgoedmannetje wrote:
It's not so much as suffer with asm code, but more of a difficulty for compilers.


Compilers don't care... The ISA can be bizarre and confusing, or neat and elegant... it makes no difference to the compiler at all. But as a Human I find 68k much easier than some horrific compiler oriented ISA like PPC for example.

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Compilers already make, so to say, sub-optimal binaries, and these flaws in CPU design really doesn't make things better. I think lots and lots of cpu cycles are being wasted.


I doubt a human could make code as efficient as a compiler on a modern CPU... Modern CPU's have hidden register renaming schemes, instruction scheduling, caching policies... the list is endless... I doubt you could know all the optimization rules now!

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Don't get me wrong, I really like backwards compatibility, but I rather see backwards compatibility as expansion rather than being used as a base.


The ISA is irrelevant with regards to performance, other than the big things like the removal of difficult to optimize instructions and addressing modes...

Read: :-)
http://arstechnica.com/cpu/2q00/x86future/isa-future-1.html

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Re: Does eight bit computing excite you?
« Reply #3 on: February 28, 2009, 05:52:01 PM »
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persia wrote:
I haven't seen assembly language in 20 years, since most computer chips are multicore nowadays does that make the assembly language more complicated?


The asm code of a multicore chip is not more complex... but writing applications that take advantage of multiple cores is much more complex... threading is a difficult topic at the best of times..

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Re: Does eight bit computing excite you?
« Reply #4 on: March 01, 2009, 01:12:14 PM »
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Speelgoedmannetje wrote:
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bloodline wrote:
I doubt a human could make code as efficient as a compiler on a modern CPU... Modern CPU's have hidden register renaming schemes, instruction scheduling, caching policies... the list is endless... I doubt you could know all the optimization rules now!
Ehm, I see it totally different.
Compilers have can compile anything, they're made to expect everything, so they have to exclude anything else, so to say.
Your code will always be completely different from compiler code because the compiler isn't and cannot be aware of what you want.
While you are!


Yeah, I understand what you are saying. But the whole RISC idea eliminates your options, you only really have a limited number of ways to implement any particular algorithm... This allows the chip designers to optimize the CPU's operation.

Compilers and CPUs are note developed in isolation anymore. They are both working to the same goal... more efficient execution.

Ok, there is the argument that the compiler does have to generalize... But after looking at the source code for Micropolis (the original SimCity), I have no idea how it could even be written in ASM! Working in a high level language gives you far more power over complex programming!

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Yes, the compiler can make things a hell of a lot faster according to mathematic rules and special instructions. But it can't make the code more straightforward.


Modern CPUs aren't meant to be programmed directly any more.

Anyway, to drag this back on topic... No, I would hate to have to go back to the 8bit days... For me working in C++ using Apple's Xcode IDE is far more comfortable.

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Re: Does eight bit computing excite you?
« Reply #5 on: March 01, 2009, 02:14:38 PM »
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ChuckT wrote:
Can a market for 6502 Computers exist anymore?

If you were asked to develop material for learning, what would you say?

If you attached an IBM video chip to a 6502, would it be a worthwhile computer to get involved in?

I was thinking that it would be easier to develop more eight bit systems into something that the Commodore 64 never was but I think a lot of people are hooked on game cube and x-box.


It just occured to me that if you want to do some 8bit development with access to modern hardware... simply buy a normal übercheap PC and run it in "Real Mode" :-D

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Re: Does eight bit computing excite you?
« Reply #6 on: March 09, 2009, 11:10:59 AM »
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Speelgoedmannetje wrote:
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trekiej wrote:
@ ChuckT
look at www.parallax.com ,it has an 8 core MCU called the propeller.
Toys!
Damn, I want to play with that  stuff...

Got no money though  :cry:


Cheer up Speel! Read this instead :-)

http://www.cs.cmu.edu/~fp/courses/15213-s06/misc/asm64-handout.pdf