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Paula Abdul and the Power Mac 8100/110

joevt said:
The Copland Disk Based Open Firmware for NuBus Power Macs ( https://tinkerdifferent.com/threads/powermac-7100-and-linux.4368/post-38377 )
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That sounds amazing, like the inverse concept of the on-disk New World ROM with OF chip-ROM!! I guess it'll work on my PB1400c?

dougg3 said:
<snip> PowerPC asm scares me. :)
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I've done a lot of Z80, 68000, 8086, ARM(Cortex) assembly and PPC asm scares me too! The real problem for me is that the mnemonics are all a bit mad: random lengths alongside 'eieio' which belongs on MacDonald's farm [they must have created it for laughs]. In some ways it'd be better to blend ARM-style mnemonics with PowerPC, because all the basic functionality will be the same, e.g. adding 'S' if the instruction updates flags. A one-page assembly/summary sheet would help a lot (I guess these exist).

This is quite a useful summary:


It's only 3 pages long.
 
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cheesestraws said:
yeah but aarch32 is the king of assembly languages and everything else is downhill from there ;-)
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LOL! I like AARCH32 assembly as well as Thumb, but my favourite still has to be Motorola 68000 (though I quite like MSP430 for the simplicity). All of these trace their ancestry back to the 6502, 6800 which in turn derive from the pdp-8 and pdp-11; which may also be inspired by the MIT Whirlwind.

Assembly languages for CPUs designed not to be programmed in assembly always end up being more arcane IMHO, because, I think the designers want to push you into using a high-level language with assembly just for compiler-writing elites.
cheesestraws said:
(Sorry, I'll stop derailing the thread, just wanted to annoy people)
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Assuming RISC-V doesn't dominate in the end (it's not particularly better than AARCH64, except for the licensing model), we'll all be in camp ARM and the rest of us will have to get used to being annoyed ;-) .
 
dougg3 said:
I tried changing the machine ID to 3010 to match my hardware, but then MAME just has a black screen. I was trying to figure out how to hack MAME to emulate an 8100/110 so I could try the easter egg, but I quickly realized I was getting myself into something deeper than I have time to tinker with right now. Plus, PowerPC asm scares me. :)
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The SuperMario code I pointed to indicates that a real 6100 returns 0x3010 from the hardware, but then it checks if it can freely set and read back bits 2 and 3 of the DMA control register for the SCSI bus. If it can't it's "first silicon PDM" and it doesn't change the ID. Otherwise, it checks if the second SCSI bus is present and IDs as a 53C96 and sets the ID to 0x3013 if it is and 0x3011 if it isn't. The PPC reset handler does the same check right after sizing the RAM. In the words of Gary Davidian:

;# Due to a bug in the first silicon PDM ASICs, cache snooping updates of the L2 cache
;# do not work correctly during DMA cycles. To temporarily work around this, we setup
;# the L2 cache to only cache instructions.

Just changing that isn't sufficient to get MAME past the chime when the ID's set to 0x3010 though, so I'll keep digging.
 
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Arbee said:
The SuperMario code I pointed to indicates that a real 6100 returns 0x3010 from the hardware, but then it checks if it can freely set and read back bits 2 and 3 of the DMA control register for the SCSI bus. If it can't it's "first silicon PDM" and it doesn't change the ID. Otherwise, it checks if the second SCSI bus is present and IDs as a 53C96 and sets the ID to 0x3013 if it is and 0x3011 if it isn't.
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Nice, that's way more complicated than I expected! And I guess the 7100 just always responds with a good ID.

I finally ended up reproducing the Paula Abdul easter egg using @joevt 's DingusPPC fork. The magic incantation ends up being to use the newer 9B7A3AAD ROM. With the newer ROM, the 1.1 PowerPC enabler loads correctly for me even without any hacks to it -- even on a 6100/60.

Then you just drag "secret about box" to the desktop as usual, and this pops up:

1751640091726.png

After you click the mouse, it falls through to the normal breakout easter egg. Edit: I see it blip on the screen for a moment, anyway. I'm not sure if it actually continues through with it or not.

Snial said:
The real problem for me is that the mnemonics are all a bit mad: random lengths alongside 'eieio' which belongs on MacDonald's farm [they must have created it for laughs].
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I definitely agree! 🤣
 
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It works with a real Power Mac 6100/66 ! (i have a spare ROM) !

I will try to make a video about that, thank you !
 
Dandu said:
It works with a real Power Mac 6100/66 ! (i have a spare ROM) !
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Oh that's interesting! So did your 6100/66 have the older 9FEB69B3 ROM originally? I wonder if the 6100/66 didn't need the newer ROM or something.

Today I ordered a newer ROM to put in my 6100/60 for fun.
 
dougg3 said:
Oh that's interesting! So did your 6100/66 have the older 9FEB69B3 ROM originally? I wonder if the 6100/66 didn't need the newer ROM or something.

Today I ordered a newer ROM to put in my 6100/60 for fun.
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Yes, the ROM inside the Mac was the 9FEB69B3. I'm not sure if this the original ROM, by the way, but the Mac is working with System 7.5 and Mac OS 8.6.

I have tried with the 9B7A3AAD ROM and the Mac boot with System 7.5, but not with Mac OS 8.6 (i have an error).
 
So, the Easter Egg with a real Mac (Power Mac 6100/66). The message (Fall/Winter...) is not on the PICT. I suppose there is a thing with the Gestalt ID 31 (Paul's Desk machine) too.
 

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Dandu said:
So, the Easter Egg with a real Mac (Power Mac 6100/66). The message (Fall/Winter...) is not on the PICT. I suppose there is a thing with the Gestalt ID 31 (Paul's Desk machine) too.
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Yep, you'll see that text is also in my DingusPPC screenshot. It seems to be drawn by code in 'timd' resource ID 13. 'STR#' ID -16651 contains the text, and the code shown below loads it. Looks like it also titles the window "Paula's Favorite" but you can't see it.

I think the Paula's Desk Machine text would show up in About this Macintosh if you had a computer with that gestalt ID. 'STR#' ID -16395 contains text for each gestalt ID that shows up there. It provides some interesting insight about the various gestalt IDs. For example, both 47 and 113 are labeled as the 7100/80, and there are gestalt IDs for all the unreleased speed variants like 8100/60 for instance.

Here's the code that sets up the window.

1751717873209.png
 
Nice write-up and video, Pierre! I just confirmed it also works on my 6100/60 after the newer ROM (part number 341-0757) arrived.
  • 341-0741 is the original ROM (9FEB69B3)
  • 341-0757 is the new ROM (9B7A3AAD)
PowerPC Enabler 1.1 only loads if you have the newer ROM installed. I can tell because with the factory ROM installed, it just says Welcome to Macintosh, but with the newer ROM installed, it says Welcome to Power Macintosh (in Spanish).

BTW, Apple's hardware dev note for the speed-bumped 6100/7100/8100 seems to indicate that the 6100/66 still came with the old ROM:

1752336354605.png

If that is true, it would indicate that this easter egg is likely only reproducible on a 7100/80, 8100/100, or 8100/110 unless you've swapped in a newer ROM.
 
dougg3 said:
If that is true, it would indicate that this easter egg is likely only reproducible on a 7100/80, 8100/100, or 8100/110 unless you've swapped in a newer ROM.
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I tried it on my 7100/80. No go, sadly. It has the original ROM and needs the v1.1.1 enabler. The Easter Egg dance produces only the regular System 7.5 breakout egg.
 
cgp said:
I tried it on my 7100/80. No go, sadly. It has the original ROM and needs the v1.1.1 enabler. The Easter Egg dance produces only the regular System 7.5 breakout egg.
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Did you try it with the Spanish 1.1 enabler from the July 95 Dev CD? (E-009-2332-A(DT).image). They removed the egg from the 1.1.1 enabler. And they accidentally left the old 1.1 version on this particular disk.
 
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