Looking for a 68060 with FPU & MMU

[guest11527]

I see. Perhaps the ROM early startup code Initializes the FPU with FRESTORE? The 68060 has a different sized stack frame that is incompatible with 68881-68040 FPU stack frames. Most 68060 libraries will patch the most common problem with FRESTORE (the FPU is not initialized for each shell program so the compiler or programmer needs to do it). FPU initialization code is possible that supports all 68881-68060 FPUs. This is what we did for the vbcc compiler which needs no patching:

__fpu_init:
     clr.l -(sp)
     clr.l -(sp)
     clr.l -(sp)
     frestore (sp)
     lea (12,sp),sp
     rte

It might be good to know if you want to try to fix the code in the ROM(s) and burn new ones.

It is more complicated than this. Yes, exec init uses an FRESTORE to test the presence of a FPU, but the problem does not go away by patching of this. The second problem is the exec task dispatcher, or rather the stack frame exec uses for saving the FPU context when it switches between tasks. The exec scheduler thus also requires patching to be able to work with 060's.  

What the 060 library does is that it *in addition* includes a patch to exec that discovers some popular mis-use cases of FRESTORE, most notably the MANX/C Compiler startup code which uses FRESTORE to initialize the FPU. The patch just detects this startup code and works around it.

[guest11527]

The fake MC68060 looks pretty good, especially the mask information on the upper right hand corner.

So, what are these fake 68060 in reality? An older mask, just painted over, or a different chip (LC, EC?).  If these chips wouldn't have the bugs of the early masks, that would probably be even ok no matter whether Motorola manufactured them or not.

[matthey]

It is more complicated than this. Yes, exec init uses an FRESTORE to test the presence of a FPU, but the problem does not go away by patching of this. The second problem is the exec task dispatcher, or rather the stack frame exec uses for saving the FPU context when it switches between tasks. The exec scheduler thus also requires patching to be able to work with 060's.  

Will FPU stack frames be generated by the exec task dispatcher if the FPU is not in use? Are there any FPU instructions in early startup before the possibility to do software patching? Perhaps a kickstart ROM chip for an Amiga without an FPU would be a good choice to start with?

What the 060 library does is that it *in addition* includes a patch to exec that discovers some popular mis-use cases of FRESTORE, most notably the MANX/C Compiler startup code which uses FRESTORE to initialize the FPU. The patch just detects this startup code and works around it.

Of course the 68060.library would still be necessary. I was suggesting a minimally patched ROM that was good enough to make it out of early startup without crashing.

So, what are these fake 68060 in reality? An older mask, just painted over, or a different chip (LC, EC?).  If these chips wouldn't have the bugs of the early masks, that would probably be even ok no matter whether Motorola manufactured them or not.

See Cosmos 2nd post in this thread.

(WARNING ON EBAY WITH UTSOURCE AND 68060RC60 : FAKE, I PURCHASED TWO, AND RETURNED = 68LC060 REBADGED WITHOUT FPU)

[donpalmera]

I have seen them sell used pulls of chips as new that had the pins HASL(hot air solder leveled) to look somewhat new.

HASL is a PCB finish. Has nothing to do with recycling components.

Yes utsource sells the same fake parts that every other Chinese broker does.. because they all source their parts from the same markets. Sometimes it's worth the risk. i.e. I have tons of 68SEC000 parts, some of them have suspect markings, but they all work and they were considerably cheaper than digikey so whatever. They could be 68EC000s for all I know.

There are guys in China that reimplement $5 chips using cheaper parts so if you think that your chances of getting a real chip that's worth around $200 from a broker in China are high you are bonkers.

If you don't want to pay the going rate but don't want to be stung look for sellers in the US or Europe that are dealing with surplus, liquidations etc.

[Cosmos Amiga]

FPU initialization code is possible that supports all 68881-68060 FPUs. This is what we did for the vbcc compiler which needs no patching:

__fpu_init:
     clr.l -(sp)
     clr.l -(sp)
     clr.l -(sp)
     frestore (sp)
     lea (12,sp),sp
     rte

No, we only need to disable the Fpu with these 040-060 adapters...


I tired to write "040-060 adapters", it's lame...

Need to find a name for them !

Any suggestions welcome ! Please, go go go...


I start :

ThunderDrome 060 ?
WaspNest 060 ?
EaglesRoad 060 ?

[Cosmos Amiga]

move.l $0010.w,d2
lea _nofpu_060(PC),a0
move.l a0,$0010.w
moveq #2,d1
movec PCR,d0
and.l   d1,d0            ; 2 = %0010
cmp.l   d1,d0
beq.b _nofpu_060
fnop
movec d1,PCR            ; = disable the 060 Fpu
_nofpu_060
move.l d2,$0010.w

This routine should works on every 68k : coders, it's ok ?

[guest11527]

This routine should works on every 68k : coders, it's ok ?

No. First, this code is supervisor only. Second, you do not know where the VBR is hanging around, or whether the CPU has a VBR in first place, so check ExecBase->AttnFlags first. Third, you do not know whether anyone else is trying to work on the autovectors at this moment, thus you should probably disable interrupts for the short while. (ori #$700,sr does that, it is restored as soon as you return from the supervisor mode.).

[Cosmos Amiga]

Hey, zero system mounted here : this code is for the very first line of the exec.library

[SpeedGeek]

Many thanks to my good friend SuperCosmos (and thanks to matthey also) for the 060 adapter and Rev. 1 CPU!!!

After many hours of work (and some hair pulling, head scratching and saying a few 4 letter words) I finally got the adapter working! :cool:

First, was the hardware fix (getting my A3640 back to 25 MHz) and that was the relatively easy part. Then adding the PCLK skew compensation mod (again relatively easy).

Next, building a new Kickstart ROM compatible with the 060. Should have been relatively easy but very difficult due to some corrupt files in my Remus build directory. (Also, complicated a bit by the 2 separate 040 and 060 exec.library's needed). :furious:

Anyway, the end result is in A3660.jpg (for you curiosity seekers).

[Cosmos Amiga]

Super !

You can push 68060 rev1 at 60 Mhz : this will give you a +20% extra CPU power !!

A small fan glued on one side will help a lot to dissipate the heat into your A3000D desktop...

[matthey]

@SpeedGeek
Awesome! I hope you do a full writeup when you are done playing.

You can push 68060 rev1 at 60 Mhz : this will give you a +20% extra CPU power !!

A small fan glued on one side will help a lot to dissipate the heat into your A3000D desktop...

Yea, there is a good chance 60MHz would work even in the 3000 case but a little extra cooling would be good. The 68060 would generate less heat than an overclocked 68040 for sure.

[magnetic]

I would say NOT to OC any board that goes in a 3000D. Its hot enough already. These boards are rare and valuable why stress the components for just slight increase in speed? (That you need for what exactly??)

[NorthWay]

2 separate 040 and 060 exec.library's needed

Why can't you use a common library for both?

[mechy]

HASL is a PCB finish. Has nothing to do with recycling components.

Yes utsource sells the same fake parts that every other Chinese broker does.. because they all source their parts from the same markets. Sometimes it's worth the risk. i.e. I have tons of 68SEC000 parts, some of them have suspect markings, but they all work and they were considerably cheaper than digikey so whatever. They could be 68EC000s for all I know.


There are guys in China that reimplement $5 chips using cheaper parts so if you think that your chances of getting a real chip that's worth around $200 from a broker in China are high you are bonkers.

If you don't want to pay the going rate but don't want to be stung look for sellers in the US or Europe that are dealing with surplus, liquidations etc.

Its common in china to do solder pulls and relevel the solder on the legs to look new and pretty, HASL was the easiest way to describe it since it is basically the same thing,just on chip legs,obviously you can still tell quite easily.

no one said you would get a new full 060 cheap from china, but used pulls are common as here.

It is possible to get full 060's but its hit and miss.I have gotten some full chips with reasonable prices before, so i know its possible.

many times i just buy used MVME board to get real 060's when they are cheap enough.

[SpeedGeek]

@matthey

I've been very busy with software patching and debugging so I don't know when/if I'll find time to do a full writeup (Cosmos want's me to work on overclocking the adapter next). But thanks again for your assistance...

@NorthWay

Motorola made significant changes with each new generation of 68K CPU so code written for earlier generations usually needed some patching to make it work. Anyway, I now have a patched exec.library (45.20b) working with 030, 040 and 060! I'm sending it to Cosmos for additional beta testing, but as far as I'm concerned the Zorro2 PCB and Diag code @ $F00000 are obsolete...

[NorthWay]

Motorola made significant changes with each new generation of 68K CPU

I know. I patched my own Exec years ago to properly detect the 060, fix its status, and set the flags for it.

So I didn't really see the need for having more than one version.