So! Turns out our cpus aren't shit!

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So! Turns out our cpus aren't shit!

Postby ShaneDalton » Sun Oct 13, 2013 9:06 am

So I know someone personally who is a software engineer, he looked at the 16-bit cpu (didn't have enough time to look at the 32-bit cpu) and well he found it fine. There were some questions however
1. why are we using last in first out instead of first in first out?
2. What are our protocols?
He did say that we should still use the 32 bit cpu though.
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Re: So! Turns out our cpus aren't shit!

Postby Krarl » Sun Oct 13, 2013 9:51 am

Are you talking about the dcpu or one of Zardoz designs?
I can't really say anything about the questions, but did he say his reasons to go for 32-bit?
Now when I think about it, maybe it would be good to make it 32-bit?
It shouldn't get that much slower to emulate since our real computers calculate with 32-bit, but I guess the larger addresses may slow things down? Maybe?
To be honest I don't know, just throwing around thoughts. But programming some things may get a lot easier with 32-bit numbers.
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Re: So! Turns out our cpus aren't shit!

Postby ShaneDalton » Sun Oct 13, 2013 10:15 am

He looked at the RC1600 CPU
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Re: So! Turns out our cpus aren't shit!

Postby Krarl » Sun Oct 13, 2013 10:24 am

Okay, thanks :)
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Re: So! Turns out our cpus aren't shit!

Postby Zardoz » Sun Oct 13, 2013 2:22 pm

Krarl wrote:Are you talking about the dcpu or one of Zardoz designs?
I can't really say anything about the questions, but did he say his reasons to go for 32-bit?
Now when I think about it, maybe it would be good to make it 32-bit?
It shouldn't get that much slower to emulate since our real computers calculate with 32-bit, but I guess the larger addresses may slow things down? Maybe?
To be honest I don't know, just throwing around thoughts. But programming some things may get a lot easier with 32-bit numbers.


The 32 bit CPUS :
    - Allow to work over 64KiB of RAM without using bank switching and/or segments -> More easy to program as use a flat memory model
    - The 32 bit space, can allow to remove separate IO address space, and map devices far away from the real RAM.
    - Moar registers! (Particular true in the case of the RC3200)
    - In the case of the RC3200, the instruction format allow in a easy way to decode and handle 3 operand instructions aka : ADD r0, r1, r3 (r3 = r0 + r1). The 16 bit format forces to uses 2 operand operations in a accumulator scheme : ADD r0, r1 (r1 = r1 + r0), at least with my instruction format.

ShaneDalton wrote:1. why are we using last in first out instead of first in first out?

You mean why a Stack instead of a Queue (push/pop)? Could be my ignorance, but I never see a CPU that uses a Queue instead of a Stack.
ShaneDalton wrote:2. What are our protocols?

Calling conventions, interrupt list, etc ? Or you mean the connexion with hardware devices ?

As I understand, what the Intel guys mainly dislike is that I really made is a instruction set/format, and I don't stop much to think how will be implemented at silicon level (the internal data path, and doing it isn't trivial work). In the case of the Z-16/Z-32 will be pretty hard to do. So, really I can't say that I made CPUs because we only do a part of what defines a real physical CPU.
But is really necessary to do it ? We will not build a physical CPU, we only need something that can be emulated on software, be fast to emulate, and acts like a CPU in a realistic way, from the point of view of the CPU programmer/user.
Yep, I have a blog : http://zardoz.es
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Re: So! Turns out our cpus aren't shit!

Postby master565 » Sun Oct 27, 2013 11:04 pm

You mean why a Stack instead of a Queue (push/pop)? Could be my ignorance, but I never see a CPU that uses a Queue instead of a Stack.


I don't have a lot of experience with low level languages, but I'm pretty sure you are right, they do usually use a LIFO data structure.
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Re: So! Turns out our cpus aren't shit!

Postby Zardoz » Mon Oct 28, 2013 6:48 am

Actually I have a more simple version of the CPU, if you wish to look it : https://github.com/Zardoz89/Trillek-Com ... /RC3200.md
I'm updating the VM to it.
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Re: So! Turns out our cpus aren't shit!

Postby chaoscode » Sun Nov 03, 2013 8:23 pm

As I understand, what the Intel guys mainly dislike is that I really made is a instruction set/format, and I don't stop much to think how will be implemented at silicon level

Our CPU is for a good Userexperience and SImulation only.
A Designimplementation is not necessary. because of that a Some restrictions to CPU Design are meaningless to us.

You mean why a Stack instead of a Queue (push/pop)? Could be my ignorance, but I never see a CPU that uses a Queue instead of a Stack.

I don't have a lot of experience with low level languages, but I'm pretty sure you are right, they do usually use a LIFO data structure.

There are a lot of Queues in a lot of CPU Designs. But those are NOT visible for the Programmcode/Programmer.
Those queues are only for CPU-Performance reasons becaues of Physical Restrictions.
From the view as a programmer i never have seen a queue in a CPU. (x86,x64,ARM,PIC,8051,Coldfire,68000)

What about a survey for the CPU Target Architekture?
Or at least a survey about the properties?
(Interrupt Design, Communication with Hardware, BitSIze, RISC or CISC?...)
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