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Message
From: dhineshbalu at gmail.com<dhineshbalu@g...>
Date: Tue Feb 13 12:59:38 CET 2007
Subject: [oc] TLB Design
----- Original Message -----
From: deepak_patnaik@h...
To: cores@o...
Date: Tue, 5 Mar 2002 13:55:53 +0100
Subject: Re: [oc] TLB Design
>
>
>
> u plz suggest the method of how to implement CAM specifically in
> vhdl/verilog.
> ----- Original Message -----
> From: Ali Mashtizadeh <ali@a... >
> To: cores@o...
> Date: Tue, 26 Feb 2002 18:00:48 -0800
> Subject: [oc] TLB Design
> we need aprogram for network protocol using vhdl program
> >
> >
> > Well I understand that I am supposed to use a state machine to
> do
> > the
> > comparisons. It's like this
> >
> > virtual Address->[Content Addressable Memory(State
> > machine)]->[RAM]->Physical Address
> >
> > The CAM(Content Addressable Memory) is my problem. You need to
> use
> > a
> > state machine to do the comparisons but that means if you have
> a 64
> > entry tlb then it will take 64 clock cycles. Unless you make
> the
> > state
> > machine's clock to be 64 times faster. I understand that most
> cpu's
> > break up the process into several smaller blocks of 4 or 8
> entries
> > and a
> > seperate comparator for each block but still that means I have
> to
> > use up
> > my precious DLL's. As for a TLB compatible with a 386 your
> gonna
> > have
> > fun with that. You need to make a search state machine to find
> > entries
> > out of the page tables when it is not in the TLB cache.
> >
> > You can simplify your TLB by using a direct mapped cache. But
> thats
> > not
> > too nice. (IE: you hash(in some way or form) the virtual
> address
> > and use
> > that as an index pointer. It can be something like the least
> > significant
> > bits of the virtual address(ofcourse after the first bits that
> are
> > less
> > than your page size.) I am concidering that method since its
> > simpler. I
> > personally will use several parrallel direct mapped caches so
> that
> > to
> > addresses with the same hash can exists on my tlb at the same
> time.
> >
> > Can someone tell me what they have done for their TLBs?
> >
> > Ali
> >
>
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