On 7/27/11 2:31 PM, Phil Blundell wrote: > On Wed, 2011-07-27 at 12:19 -0500, Mark Hatle wrote: >> On 7/27/11 10:25 AM, Phil Blundell wrote: >>> On Wed, 2011-07-27 at 09:58 -0500, Mark Hatle wrote: >>>> For the tune names.. armv5 means I want classic ARM instructions, while >>>> armv5t >>>> means I was thumb instructions. >>>> >>>> So armv5 and armv5t are distinct in the contents of the tunings. >>> >>> Ah, I see. Does that go for v4t too? I can imagine cases where you >>> would want to say "select the v4T ISA but generate ARM code not Thumb". >> >> Yes, for all of them, the TUNENAME selects the features that you want to use >> to >> compile, and suggests the other information like compatible architectures. >> >> In the case where you want to build primarily one, and optionally the other >> the >> tunename makes it easy.. >> >> Say you want all of your system thumb, except for a few specific programs.. >> >> TUNENAME = "armv4t" >> >> TUNENAME_pn-mysql = "armv4" >> >> In the opposite case, where you want everything ARM, except for a few thumb: >> >> TUNENAME = "armv7" >> TUNENAME_pn-bash = "armv7t" > > I'm not quite sure that this answers the question I was trying to ask. > > The thing about v4/v4T is that, unlike later versions of the > architecture, plain v4 doesn't include the BX instruction. So, if you > want your code to be interworking-capable without requiring linker > shims, you need to specify -march=armv4t (and -mthumb-interwork) even > for CUs that you want to compile as ARM code. > > If the architecture name implies the execution state then it doesn't > appear as though there is going to be any way to select -march=armv4t > without also selecting -mthumb, which would make it impossible to build > interworking-capable ARM-state code for v4T.
It was my understanding that interwork was always enabled these days. Does interworking require a thumb compatible arm core? --Mark >> So then the question is.. with OE-core and core based distros.. are there >> enough >> armv5 (w/ or w/o e) left to justify having both? If not.. then we select the >> one with the 'e' since it's more common. > > I'm not aware of anybody using a non-e ARMv5 with OE at all. The two > most common v5-class implementations, by some margin I think, are the > ARM9x6 family and Xscale, and all of those are at least v5TE. > > p. > > > _______________________________________________ > Openembedded-core mailing list > [email protected] > http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core _______________________________________________ Openembedded-core mailing list [email protected] http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core
