Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
I'd be amazed if LLVM could determine that the value won't change between calls!

Sorry, but I do not understand this. One thread == one interpreter == one stack. Code cannot call between threads, and threads do not switch stacks (easily).

If the address of the current interpreter was stored in (say, on Intel) the FS or GS register, when the scheduler preempts one thread and loads another, it would restore that register, just as it does for the SP and IP and all the others. Every time a particular thread/interpreter is running, its context would be available in that register; and (on Intel) all the offsets within that context structure would be available as indexed addressing via that segment register.

On other processors, mostly register rich compared to Intel, the same thing could be done.

Basically, the 'reserved' register is loaded with the context when the thread (including the first) is started, and if nothing else is allowed to touch that register -- pretty much guaranteed on Intel -- it value is always available without needing to pass it around to every function.

LLVM might need a custom addition to its code generation routines (for each platform), to support that, but LLVM allows that to be done.


With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

RIP Neil Armstrong


In reply to Re^11: Perl 5 Optimizing Compiler, Part 4: LLVM Backend? by BrowserUk
in thread Perl 5 Optimizing Compiler, Part 4: LLVM Backend? by Will_the_Chill

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • Outside of code tags, you may need to use entities for some characters:
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others chilling in the Monastery: (6)
    As of 2014-08-30 07:46 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The best computer themed movie is:











      Results (291 votes), past polls