Compilation

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admin
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Compilation

Post by admin » Tue Oct 11, 2005 12:41 am

I have a working, but currently immature and not very exciting, compilation phase in Aemulor now. No prizes for guessing which machine this is primarily aimed at ;) (Since we can't use the hardware breakpoints employed by the StrongARM engine on the ARM9)

I'm referring to it as compilation because it's not strictly speaking a JIT, since it compiles the whole application up front rather than dynamically deciding what to compile. This means that its memory footprint will be larger but with even our heaviest 26-bit applications having no more than about 1MB of code, I don't think this is an issue and the speed gain will probably be more valuable.

At the moment, I anticipate the compilation engine's speed to be roughly on a par with that of the StrongARM engine but with the introduction of optimisations (both in the engine itself and in the engine's output since I can tune the code for the XScale or ARM9 as I compile it) it should improve.

Time will tell...

admin
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Posts: 381
Joined: Wed Oct 23, 2002 11:25 pm
Location: Cambridge, England
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Post by admin » Wed Oct 12, 2005 6:05 am

Having now discovered the (/an?) embarrassing oversight which early in the execution of a 26-bit app caused it to discard all compiled code, reverting to the ARM610 emulation engine, I think I now understand why the speed wasn't very impressive ;)

Still far too early to get any feel for the true speed of the code but it definitely looks to have merit because a simple test of loading a text file into my old 26-bit wordprocessor (!Scribe) exhibits a 2-3x speed up over the StrongARM engine.

At the moment the code's not sufficiently complete to run large apps like Publisher or PipeDream (the latter is of particular interest because it's sluggish even under the SA engine).

Still no optimisations, cunning compilation tricks, blah blah blah....very rough & ready.

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