bobd@hpuxa.ircc.ohio-state.edu (Bob DeBula) (06/20/89)
Well, I got my 68851 PMMU installed in my MAC-II, now (without buying Virtual or A/UX) does anyone know how to test it? I'm planning on waiting until System 7.0 to actually exploit it, but I would like to assure myself that it's properly installed and functioning. Any ideas netters? -=- ------------------------------------------------------------------------------- Bob DeBula | Internet: bobd@hpuxa.ircc.ohio-state.edu The Ohio State University | Disclaimer: These are my views, not the U's
davely@mcrware.UUCP (Dave Lyons) (06/21/89)
In article <134@nisca.ircc.ohio-state.edu> bobd@hpuxa.ircc.ohio-state.edu (Bob DeBula) writes: > >Well, I got my 68851 PMMU installed in my MAC-II, now (without buying >Virtual or A/UX) does anyone know how to test it? I'm planning on waiting >until System 7.0 to actually exploit it, but I would like to assure myself >that it's properly installed and functioning. Any ideas netters? If you have access to an assembler you could just write a little assembly code to try moving a register from the PMMU into d0, say, and see if it works or if you get an illegal instruction error (bomb box number 3). If your assembler won't generate pmmu instructions you can probably just use "dc.w" and put the object code in directly as follows: move.l d0,-(sp) ; save d0 dc.w $f000,$4200 ; moves pmmu tc register into d0 move.l (sp)+,d0 ; restore d0 You could do the same kind of thing with LightSpeed C as follows: void testpmmu() { asm { move.l d0,-(sp) dc.w 0xf000,0x4200 move.l (sp)+,d0 } } If you call this function and it works I'd say the pmmu is o.k. Finally, now that I've wasted all this band width, I would guess that if your system runs with a PMMU installed the chip must be working at least partially since the address lines from the '020 have to go through the PMMU on their way to the bus. I hope this helps (or at least makes sense). -- Dave Lyons - reach him at ...!sun!mcrware!davely Ask not from whom the opinions come. They come from me. ---------------------------------------------------------------------- "Gravity is arbitrary" - Calvin
paul@taniwha.UUCP (Paul Campbell) (06/21/89)
In article <134@nisca.ircc.ohio-state.edu> bobd@hpuxa.ircc.ohio-state.edu (Bob DeBula) writes: >Well, I got my 68851 PMMU installed in my MAC-II, now (without buying >Virtual or A/UX) does anyone know how to test it? I'm planning on waiting >until System 7.0 to actually exploit it, but I would like to assure myself >that it's properly installed and functioning. Any ideas netters? actually a very simple (and quite good) test is to plug in the PMMU and turn the Mac on. If you get a happy Mac the the PMMU is OK (they actually have to use the PMMU to map to the crazy 24-bit addressing ....). Of course this does not test all the internal functions of the PMMU but at least you know the TLB works and that it walks page tables etc Paul -- Paul Campbell, Taniwha Systems Design UUCP: ..!mtxinu!taniwha!paul Oakland CA AppleLink: D3213 Q: How many men does it take to pilot the Exxon Valdez? A: One and a fifth.
steve@violet.berkeley.edu (Steve Goldfield) (06/21/89)
In article <383@taniwha.UUCP> paul@taniwha.UUCP (Paul Campbell) writes: #>In article <134@nisca.ircc.ohio-state.edu> bobd@hpuxa.ircc.ohio-state.edu (Bob DeBula) writes: #>>Well, I got my 68851 PMMU installed in my MAC-II, now (without buying #>>Virtual or A/UX) does anyone know how to test it? I'm planning on waiting #>>until System 7.0 to actually exploit it, but I would like to assure myself #>>that it's properly installed and functioning. Any ideas netters? #> #>actually a very simple (and quite good) test is to plug in the PMMU and #>turn the Mac on. If you get a happy Mac the the PMMU is OK (they actually #>have to use the PMMU to map to the crazy 24-bit addressing ....). Of #>course this does not test all the internal functions of the PMMU but #>at least you know the TLB works and that it walks page tables etc #> #> Paul #> #>Paul Campbell, Taniwha Systems Design UUCP: ..!mtxinu!taniwha!paul #>Oakland CA AppleLink: D3213 #>Q: How many men does it take to pilot the Exxon Valdez? #>A: One and a fifth. I also installed a 68851 PMMU and a 68882 in my Mac II. I've also been wondering if I was successful. Are you suggesting that because I was able to turn the machine back on with everything functioning, that means both chips are properly installed? I'll admit I was relieved that the system seemed unaffected, but is it possible for something to be wrong with one or both of the chips without a visible problem? Steve Goldfield
paul@taniwha.UUCP (Paul Campbell) (06/23/89)
In article <25656@agate.BERKELEY.EDU> steve@violet.berkeley.edu (Steve Goldfield) writes: >I also installed a 68851 PMMU and a 68882 in my Mac II. I've also >been wondering if I was successful. Are you suggesting that >because I was able to turn the machine back on with everything >functioning, that means both chips are properly installed? >I'll admit I was relieved that the system seemed unaffected, >but is it possible for something to be wrong with one or >both of the chips without a visible problem? I can't vouch for the '882 (just try some floating point). But in order for a Mac II to work at all with a PMMU in it has to work with some basic functionality (it has to be able to walk single level page tables, translate virtual addresses etc). The PMMU has all sorts of modes and other crud in it, no one uses all of them, most people use a very small subset. In the '030 MMU Mot. actually removed a lot of stuff that noone seemed to be using in the PMMU - this has the added effect that for compatability no one will use the stuff that got left out. Paul -- Paul Campbell UUCP: ..!mtxinu!taniwha!paul AppleLink: D3213 "Free Market": n. (colloq.) a primitive fertility goddess worshipped by an obscure cult in the late 20th C. It's chief priest 'Dow Jones' was eventually lynched by an enraged populace during an economic downturn (early 21st C).
dware@macknife.UUCP (06/23/89)
/* Written 2:40 pm Jun 19, 1989 by hpuxa.ircc.ohio-state.edu!bobd in macknife:comp.sys.mac */ /* ---------- "68851 PMMU Test?" ---------- */ > Well, I got my 68851 PMMU installed in my MAC-II, now (without buying > Virtual or A/UX) does anyone know how to test it? I'm planning on waiting > until System 7.0 to actually exploit it, but I would like to assure myself > that it's properly installed and functioning. Any ideas netters? If you can find the Apple Mac II test routines, believe GEnie and Compuserve both have them, there are PMMU test routines there. Don Ware /* End of text from macknife:comp.sys.mac */