Re: Compiler Hosts and Targets

[Steven Hovater <nh-ho@mediaone.net>]

Rational does indeed have a validated Ada (83 and 95) compiler (ApexCross)  for
the Tornado/Intel.

Cheers,
Steve

dennison@telepath.com wrote:

> In article <75c6ir$l61$1@nnrp1.dejanews.com>,
>   dewarr@my-dejanews.com wrote:
> > In article <755s4v$7vh$1@nnrp1.dejanews.com>,
> >   dennison@telepath.com wrote:
> > > Non-Ada issue: There is no such thing as Pentium/VxWorks,
> > > unfortunately.
> > > There is an Intel3(or4)86/VxWorks target, which may be
> > > used on Pentiums
> > > (although it will run *slower* unless you change the
> > > caching behavior!). But
> > > if you use that on a Pentium it will not generated
> > > Pentium optimized code.
> >
> > Not quite clear what "it" refers to here. VxWorks is not
> > in the business of "generating" code at all! It is of
> > course the case that compilers typically used with VxWorks,
> > including gcc, and GNAT, can of course generate Pentium
> > optimized code.
>
> Of course "it" was a simplification. I didn't think anyone here was
> interested in the gory details. But since you seem to insist upon them I'll go
> ahead. The rest of you may want to go get a sandwich or something. :-)
>
> Tornado, the system that came w/ our VxWorks (targetted to a PC clone)
> contained the source code for the OS, a BSP for the PC, gcc, and a GUI
> environment for building the OS and user programs. The BSP's that are
> available are for PC386 and PC486 (no "PCPentium", no "PCPentiumII"). The gcc
> we get is a prebuilt version for the 386 (not "Pentium", 386). With this
> system as shipped, you cannot build Pentium targetted code. (I suppose its
> possible they have a bare Pentium BSP, but that wouldn't be much fun to use
> on a PC unless you enjoy writing device drivers).
>
> The compiler we use is the GreenHills Ada compiler, which to my knowledge is
> the *only* validated Ada compiler on this platform. (Rational does have some
> VxWorks compilers for other CPU's). The GreenHills compiler cannot build
> PentiumII or Pentuim optimized code; only 368 and 486.
>
> The bug I was referrring to is a known VxWorks bug in this configuration. The
> OS performs a cache invalidate whenever a task switch occurs. Apparently this
> instruction takes roughly 5 cycles on the Pentium, but 2000 on the Pentium
> II. If you run your system with relatively high rate tasks (2KHz in our
> case), this causes a Pentium II system to run *slower* than Pentium I. We
> have measured this in house (and we are not the only ones). The folks at
> WindRiver actually sent someone out here to track it down, and ended up
> changing our OS source files to get around the problem (*much* better now).
>
> Everyone back from the fridge yet? Good. The point is that while you can run a
> VxWorks system on a Pentium PC, neither VxWorks, not Tornado, nor Green Hills
> are really designed for it.
>
> --
> T.E.D.
>
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--
Steven
Hovater
svh@rational.com
Software Engineering Consultant
Phone/fax:781-676-2565/2500
Rational
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