Minimig Review completed!

[TobiFlex]

TheDaddy wrote:
Well...I have tried renaming kickstart 2.04 and 3.0 to KICK.ROM and all I get is a red screen and nothing else.

It seems only to work with 1.3 (512K).

I was going to test the failing games with 2.04 but it won't boot (just red screen). :-?

RedskullDC has done his tests with the minimigtg68:
minimigtg68

I have never seen a picture from a minimig with a 2.04 bootscreen. But the minimigtg68 can boot all versions of kickstartrom.

Now I found a little but important difference in the 68sec000 and the TG68 IP Core.

The tg68 is a 68000 Clone. But the 68sec000 insn't a 68000 and isn't a 68010. That is the Problem.

The Move from SR is priviligated in the 68sec000. Kick >= 2.04 use this Instruction to check the CPU Type.
For the kick 2.04 is the 68sec000 a 68010. But the 68sec000 has the exception stack frames from the 68000. That can't work without a patch.

But the TG68 use the Move from sr in user state and use also the 68000 exception stack frames. That works fine.

I think the TG68 IP Core is the better choose for the minimig!

Viele Grüße
TobiFlex - the creator of the TG68 Core ;-)

PS: any infos about Kick 3.1 - is there the 68sec000 known???
 

[TobiFlex]

Piru wrote:

This is not the CPU detection, it's done earlier, at FC02A8. Here a subroutine FC0546 is called. At FC0564 it does "movec d1,vbr", which is illegal instruction on real 68000 (at least). Apparently it is not illegal for 68sec000(?), and thus the processor is considered a 68010. [EDIT] It is illegal on sec000, too, see below for update [/EDIT]

You are right. "movec d1,vbr" is the Instruction to detect the 68010 and this is also illegal on the 68sec000. So the 68sec000 is detected right to 68000.

Yesterday i make a test with the TG68 Core. For the test I change the mode for the "Move from SR" Instruction to use in supervisor mode only. All Kickroms starts also fine.

But what is then the TheDaddys Problem?

TheDaddy wrote:

Well...I have tried renaming kickstart 2.04 and 3.0 to KICK.ROM and all I get is a red screen and nothing else.

It seems only to work with 1.3 (512K).

I was going to test the failing games with 2.04 but it won't boot (just red screen).

 

 :-?

[TobiFlex]

riftcon wrote:

Which document says it's supervisor only?

M68000PRM.pdf Page 6-17

[TobiFlex]

riftcon wrote:

Interesting. 1-15 in EC000UM.pdf says it isn't.

The EC000UM.pdf describe the SCM68000. This is a freescale core processor. With other words: this is the 68K IP Core from freescale and this is not a document about the 68EC000.

[TobiFlex]

Perhaps is "Move from SR" privileged on the 68EC000 and not privileged on the 68SEC000
Very intresting!

What about "Move from CCR"? It is illegal on the 68000.
[EDIT]
What's matter on the 68ec000 and 68sec000?
[/EDIT]

[TobiFlex]

riftcon wrote:
Update: Had my friend try out a program with the "move from ccr" instruction on the MiniMig. This crashes, so the SEC looks like it's a standard 68000 so far...

Ah! Thank you for this. Now we must find somebody who can try this on a 68EC000. Is anybody here???

[TobiFlex]

Piru wrote:
@TobiFlex

What about "Move from CCR"? It is illegal on the 68000.

It is.

That is what i say.
but i also ask
"What's matter on the 68ec000 and 68sec000?"

For the 68SEC000 is the answer:
it is illegal.
But now the question:
Is "Move from CCR" on the 68EC000 illegal or privileged?