[Toybox] big endian problems

[Isaac Dunham]

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?
> 

http://www.linux-mips.org/wiki/Highmem
says it's basically that only 512MB are theoretically addresseable as lowmem,
and some of that is reserved so only half can be used.

HTH,

Isaac Dunham

 1414195703.0