ARMv4 vs ARMv6

[Carsten Haitzler (The Rasterman)]

On Thu, 16 Oct 2008 12:49:23 +0200 Harald Welte <laforge at openmoko.org> babbled:

> I don't know the details of ARMv4/v6/VFP interaction, but I believe it is
> all the same ABI (EABI), and you should very well be able to link a ARMv6
> application against an ARMv4 library.

as best i know arm v4,v5,v6 etc. etc. is much more like when intel ADDED mmx,
mmx2, sse, sse2, sse3/4 etc. etc. and then amd added 3dnow. it's extensions to
the core instructionset for arm. if you build for the lowest common denominator
(pick an old arm.. like armv4) it will work on v5,v6,v7 etc. like i386 works on
486, pentium, pentium+mmx, etc. etc.

i386 vx xn6_64 is a different matter as it literally is not an extension - it's
a break. you flip between 2 different modes.

so as such the arm version stuff is quite sane. new binary with optimised
builds for newer arms wont work on older, but vice-versa is fine. until arm
feels the need to go 64bit... :)

-- 
------------- Codito, ergo sum - "I code, therefore I am" --------------
The Rasterman (Carsten Haitzler)    raster at rasterman.com