[Aboriginal] [Toybox] big endian problems

Isaac Dunham ibid.ag at gmail.com
Fri Oct 24 17:08:23 PDT 2014

On Fri, Oct 24, 2014 at 02:27:46PM -0700, James McMechan wrote:
> >> TP-Link mr3020 - aboriginal will build MIPS, but static binaries do not run on openwrt kernel
> >> hoo-too Tripmate Elite - also MIPS not yet tested
> >
> > mips has a sort of oabi/eabi thing going on, where the old mipsr4k
> > binaries I'm building (with the hard 256 meg memory constraint) are
> > being replaced by "mips32" which is some confusing thing I need to read
> > up on and has some kind of "kernel space code and userspace code aren't
> > the same thing" weirdness going on that I got half an explanation of and
> > don't understand.
> >

I can't explain that, but OpenWRT builds kernels without FPU emulation,
meaning that most MIPS routers need a soft-float ABI.

> I have just brushed up a bit on MIPS again I used to work with them a little
> I think it was a crimson honking big rack with lots of fans and big twist-lock
> 220V 30A power connectors for the racks which alas did not have the colored
> panel just big SGI brown doors, the personal Indigo we later used as a system console did
> have the coloured case in sort of blue purple. Hunh, looks like what we had was
> a SGI SkyWriter 4D/510 (crimson) R3000 system which could also have upto 256MB if you
> maxed out the memory boards in the rack with 4M SIMMs and the first console was
> likely a 4D/35 Personal IRIS also R3000.
> Even the Indigo when it switched to blackjack with standard 72pin SIMM could
> do 384MB and that was about 1991-3 and it was full 64 bit using R4000 MIPS-III the
> 32bit R3000s from the very first Indigos was from 1988 and used MIPS-I and could only do
> 96MB with SGI memory modules.
> According to some of the notes for more than 384MB you need to boot a 64bit kernel
> MIPS32 looks like MIPS-II + bits from MIPS-III, MIPS-IV & MIPS-V but without the 64bit
> mode MIPS-III (R4000) and later instruction sets all had.
> The Indy low cost pizzabox used FPM SIMMs but could only go up to 8x32MB for 256MB
> Pretty much all others of the ones using standard FPM SIMMs could take more memory
> even back in the 1990s where is this hard 256MB limit from?

says it's basically that only 512MB are theoretically addresseable as lowmem,
and some of that is reserved so only half can be used.


Isaac Dunham


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