IRC logs for #openrisc Sunday, 2013-07-28

--- Log opened Sun Jul 28 00:00:46 2013
stekernolofk: we basically just settled the date and place for orconf'1302:13
stekernand I have asked the same question about the rams several times, no-one has ever responded02:14
poke53281stekern: You are my hero. Thanks for the patches. We have to include the tlb hardware reload in or1ksim too.05:45
poke53281I am still a little bit depressed that X is not stable.05:50
poke53281So I though I play a little bit05:51
stekernhah! that's the coolest thing I've ever seen being run on an openrisc implementation06:08
stekernI'm a bit depressed that you beat me to it though =P06:09
stekernregarding hw tlb reload in or1ksim, we could probably just about copy what I have in qemu:
poke53281Yes, looks doable. I should also work on my or1ksim stuff. There is so much to do.06:31
poke53281The one thing I don't like in the tlb reload is the definition that the MMUCR registers must be zero for software dtlb refill.06:32
poke53281A flag bit would be better06:32
poke53281There are still 10 bits reserved in in the SR register. And for something important like this I would take one of those bits.06:35
stekernperhaps, but what should be done when it's zero? it'll generate a pagefault in the end, so falling back to tlb miss exception seems like a sensible thing to do06:38
stekerneven if there would be a föag for it06:38
poke53281Flag=0: always software tlb refill. Flag=1: Always Hardware TLB Refill. If the register mmucr is zero then it will try to read the pagetable from zero, which will probably lead in the end to a page fault. But almost all implementation that I have seen so far behave like this.06:51
stekernyeah, I don't really have strong feelings either way on that matter06:55
poke53281For or1ksim you have to change the refill to extend for the different tlb sizes. Unfortunately just copy and paste will not do it.06:57
stekernyou still have to write the mmucr register to enable/disable hw refill, so I don't see the huge benefit though06:57
stekernyou can have the pagetables at address 0, but that's about it06:59
stekern(or1ksim) ah, but that's a minor thing to fix07:00
poke53281Well, call it symmetry :). Otherwise it will break the consistency of the architecture.07:00
poke53281Why everything important can be enabled and disables in the SR register instead of the hardware refill?07:01
poke53281There are already flags for the MMU in it.07:01
stekernaha, you are speaking sbout *SR*, i thought you meant the reserved bits in mmucr07:03
poke53281Yes, I wrote *SR* :)07:03
poke53281I am pretty sure the original writers of the specification would have done it that way.07:04
poke53281original authors07:04
stekernyes, I'm just a sloppy reader... ;)07:08
stekernI guess that would be fine, I'll think about it some more07:10
poke53281Ok, think about it. I will write a short reply wit the suggestion tomorrow. Now I have to go to bed.07:12
stekernsleep well, and thanks07:28
stekernimmediate problem in mor1kx is that SR is only 16 bit wide, but that's not a good reason against it ;)07:34
olofkpoke53281: Have to agree with stekern. That's the coolest and most useful thing I've ever seen the OpenRISC being used for10:10
olofkstekern: Great. I was mostly interested in the date so I can book plane tickets. When is it? Wiki is not updated10:12
stekernolofk: october 12th I believe was the verdict, jeremybennett or juliusb might want to confirm15:14
juliusbfinally got around to it today17:19
stekernjuliusb: is it much harder to get to cambridge from gatwick than stansted?17:43
stekernlooking at flights, they are offering me 22 h travel in the range 180 € - 1268 € helsinki - stansted17:44
stekernhelsinki - gatwick is 3 hours straight flight for 157 €17:45
juliusbStansted is a lot closer than Gatwick, but it's not the end of the world18:18
juliusbit's just another couple of hours of travel all up18:19
juliusbstekern: are you thinking of coming Friday or Saturday?18:21
juliusbyes it looks like Helsink is not well connected to Stansted. It is a big Ryan Air hub18:30
juliusbso if ther's a Ryan Air portal of pain nearby, then I'd look at flights there18:30
hnoRyan Air do have a quite reasonable flight from Stockholm, 438:- (51€). Friday night - Monday morning.19:18
--- Log closed Mon Jul 29 00:00:47 2013

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