Messages in this thread | | | Date | Wed, 14 Aug 2013 17:20:40 +0100 | From | Jonathan Austin <> | Subject | Re: arm: Only load TLS values when needed |
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Hi André,
On 14/08/13 15:07, André Hentschel wrote: > Hi Jonathan, > Any updates on this? >
I was holding out to see the version with ldrd at the top, as discussed below - I never saw a version with that change? I'd meant to ping you to see if that was coming, sorry.
[...] >>> [...] >>>>> Now we've only got one instruction between the store and the load >>>>> and risk stalling the pipeline... >>>>> >>>>> Dave M cautiously says "The ancient advice was that one instruction >>>>> was enough" but this is very core dependent... I wonder if anyone >>>>> has a good idea about whether this is an issue here...? >>>> >>>> We could use a ldrd at the top, that'd be nearly what we have right >>>> now, don't we? >>> >>> Yea, that'd be good - as far as I can see from an 1136 TRM, the ldrd *may* be two cycles (depending on alignment of the words) but the ldr and ldrne will always be two cycles. Ahhh, the joys of modifying the fast path ;)
Was expecting to see something that reflected this discussion,
Jonny
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