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Hi,

We're interested in developing an sms emu for university work this year.
We'd like to know some things:

1-is it right that sms rom is just z80 code + data?
2-if yes, how can i know where data begins?
3-which is the best z80 core we could use?

thanks in advance,

usjt_team

Quote

> 1-is it right that sms rom is just z80 code + data?

Yes.

Quote

> 2-if yes, how can i know where data begins?

At 0.

Quote

> 3-which is the best z80 core we could use?

Marat Faizullin's one ! :)

Quote

> > 2-if yes, how can i know where data begins?

> At 0.

I feel this second point needs clarification.

The Z80 reset vector is at 0. This means that code, not data, begins at 0.

As far as I know, the SMS has no rules about the location of data (such as graphics tiles) within the address space; ROM data can be located anywhere. The only way to know where data is stored is to trace through the program code.

Good luck with your project.

Eric Quinn

Hi,

Thanks Zoop and Eric.
Eric, if I understood you right, you meant I should debug the execution of a ROM to see what is the data?

Again, thanks for the help. Zoop, Meka rules! If you don't mind, i'd like to take some more doubts off as they appear, and post some info about the emu here. May I?

Regards,

usjt_team

Quote

> > > 2-if yes, how can i know where data begins?

> > At 0.

> I feel this second point needs clarification.

> The Z80 reset vector is at 0. This means that code, not data, begins at 0.

> As far as I know, the SMS has no rules about the location of data (such as graphics tiles) within the address space; ROM data can be located anywhere. The only way to know where data is stored is to trace through the program code.

> Good luck with your project.

> Eric Quinn

Quote

> Eric, if I understood you right, you meant I should debug the execution of a ROM to see what is the data?

Well, yes and no. That wouldn't be very useful. You just don't have to separate "code" and "data", they are both handled the same way as the Z80 cpu simply read from the memory which can be either code or data.

Quote

> Again, thanks for the help. Zoop, Meka rules! If you don't mind, i'd like to take some more doubts off as they appear, and post some info about the emu here. May I?

Sure.

No, I'm not silly but most of you all talk all uptight...

"My name is Peter Bluxingtonworth and I have a Phd in
Physics from the University of Pennsylvania. I'm smart,
I'm a hardworker, and for the women out there...I have
a fantastic jawline! Ha...Hahaha!"

Lighten up. Relax. So what if you misspell? Snot uh
problem atall.

Chris :o)

None of that lame wanna-be hacker syntax shit...

"MaTrIxG47$ iz my name. I have a homepage wit tonz
uv ROMZ, WAREZ, ApplicationZ, and anything else I can
think of that I can change the S to a Z cause I'm
Kewl lik dat. I'm a member wit duh TOP 25/50/100,
I force muh Userz into voting pages, I hav uh
huge counter, and nun of muh links work."

Chris :o)

Quote

> > Eric, if I understood you right, you meant I should debug the execution of a ROM to see what is the data?

> Well, yes and no. That wouldn't be very useful. You just don't have to separate "code" and "data", they are both handled the same way as the Z80 cpu simply read from the memory which can be either code or data.

Precisely. There's no real reason to try to locate "data" in the ROM. Simply start execution by fetching from address 0 and, as long as the Z80 emulator works correctly, code and data will be handled properly.

Good luck.

Eric Quinn

Author	Message
usjt_team Guest	SMS emulator development Posted: Thu Feb 24, 2000 10:49 am
usjt_team Guest	Hi, We're interested in developing an sms emu for university work this year. We'd like to know some things: 1-is it right that sms rom is just z80 code + data? 2-if yes, how can i know where data begins? 3-which is the best z80 core we could use? thanks in advance, usjt_team

Zoop Joined: 24 Jun 1999 Posts: 1732 Location: Paris, France	Posted: Thu Feb 24, 2000 2:08 pm
	Quote > 1-is it right that sms rom is just z80 code + data? Yes. Quote > 2-if yes, how can i know where data begins? At 0. Quote > 3-which is the best z80 core we could use? Marat Faizullin's one ! :)

Eric Guest	Posted: Thu Feb 24, 2000 3:50 pm
Eric Guest	Quote > > 2-if yes, how can i know where data begins? > At 0. I feel this second point needs clarification. The Z80 reset vector is at 0. This means that code, not data, begins at 0. As far as I know, the SMS has no rules about the location of data (such as graphics tiles) within the address space; ROM data can be located anywhere. The only way to know where data is stored is to trace through the program code. Good luck with your project. Eric Quinn

usjt_team Guest	Trace code (Zoop and Eric) Posted: Thu Feb 24, 2000 5:51 pm
usjt_team Guest	Hi, Thanks Zoop and Eric. Eric, if I understood you right, you meant I should debug the execution of a ROM to see what is the data? Again, thanks for the help. Zoop, Meka rules! If you don't mind, i'd like to take some more doubts off as they appear, and post some info about the emu here. May I? Regards, usjt_team

Zoop Joined: 24 Jun 1999 Posts: 1732 Location: Paris, France	My bad, I thought he was saying "code". nt Posted: Thu Feb 24, 2000 7:03 pm
	Quote > > > 2-if yes, how can i know where data begins? > > At 0. > I feel this second point needs clarification. > The Z80 reset vector is at 0. This means that code, not data, begins at 0. > As far as I know, the SMS has no rules about the location of data (such as graphics tiles) within the address space; ROM data can be located anywhere. The only way to know where data is stored is to trace through the program code. > Good luck with your project. > Eric Quinn

Zoop Joined: 24 Jun 1999 Posts: 1732 Location: Paris, France	Re: Trace code (Zoop and Eric) Posted: Thu Feb 24, 2000 7:04 pm
	Quote > Eric, if I understood you right, you meant I should debug the execution of a ROM to see what is the data? Well, yes and no. That wouldn't be very useful. You just don't have to separate "code" and "data", they are both handled the same way as the Z80 cpu simply read from the memory which can be either code or data. Quote > Again, thanks for the help. Zoop, Meka rules! If you don't mind, i'd like to take some more doubts off as they appear, and post some info about the emu here. May I? Sure.

Chris Guest	Wow! Finally someone said some "slang" around here! Posted: Thu Feb 24, 2000 8:01 pm
Chris Guest	No, I'm not silly but most of you all talk all uptight... "My name is Peter Bluxingtonworth and I have a Phd in Physics from the University of Pennsylvania. I'm smart, I'm a hardworker, and for the women out there...I have a fantastic jawline! Ha...Hahaha!" Lighten up. Relax. So what if you misspell? Snot uh problem atall. Chris :o)

Chris Guest	But... Posted: Thu Feb 24, 2000 8:05 pm
Chris Guest	None of that lame wanna-be hacker syntax shit... "MaTrIxG47$ iz my name. I have a homepage wit tonz uv ROMZ, WAREZ, ApplicationZ, and anything else I can think of that I can change the S to a Z cause I'm Kewl lik dat. I'm a member wit duh TOP 25/50/100, I force muh Userz into voting pages, I hav uh huge counter, and nun of muh links work." Chris :o)

Eric Guest	Re: Trace code (Zoop and Eric) Posted: Fri Feb 25, 2000 12:14 am
Eric Guest	Quote > > Eric, if I understood you right, you meant I should debug the execution of a ROM to see what is the data? > Well, yes and no. That wouldn't be very useful. You just don't have to separate "code" and "data", they are both handled the same way as the Z80 cpu simply read from the memory which can be either code or data. Precisely. There's no real reason to try to locate "data" in the ROM. Simply start execution by fetching from address 0 and, as long as the Z80 emulator works correctly, code and data will be handled properly. Good luck. Eric Quinn

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