POV-Ray : Newsgroups : povray.programming : Official notice - user defined function VM data structures : Re: Official notice - user defined function VM data structures Server Time
24 Sep 2021 09:21:59 EDT (-0400)
  Re: Official notice - user defined function VM data structures  
From: Thorsten Froehlich
Date: 21 May 2018 15:20:00
Message: <web.5b031ab2eeeccf2a535efa580@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:
> Am 21.05.2018 um 18:37 schrieb E-mailyvo s gmx.net:
>
> >> To the best of my knowledge there is not, and never has been, any
> >> platform-specific code that does, or ever did, rely on these structures.
> >>
> >> If I'm mistaken there, please let me know.
> >
> > If I remember well, there was a JITC but only for the Macintosh version
> > v3.6
> > JITC for the PPC (G4, G5,…)
> > Maybe that was the reason for it?
>
> Sounds plausible, given that the comment was signed by Thorsten.

Yes, there was, or actually is, a JIT for PPC in the Mac version of 3.6. It gave
a 8-10 times gain in performance at the time, especially for complex functions.
The JIT is also the reason for the, at first sight, odd absolute position stack
design in the function VM ... it made the switching to JIT code easier as I
could skip implementing a full ABI compliant compiler. I. also had a prototype
for a x86 JIT at one time, but the x86 stack-based FPU is a real pain.

Thorsten


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