choice of gcc version for Erlang on ARM/XScale/PXA

Marthin Laubscher <>
Tue Nov 29 21:55:19 CET 2005


Thanks for the heads up Mikael. I did the test on the gumstix and got:
# erl
Erlang (BEAM) emulator version 5.4.10 [source]

Eshell V5.4.10  (abort with ^G)
1> io:format("~.16#, ~.16#~n", [16#001000000000 bsr 8,16#001000000000 bsl
8]).
16#10000000, 16#100000000000
ok
2>

Would you regard that as indication that I don't have the bug? (i.e. correct
patches was installed?)

What is the proper/best way to verify that a new Erlang (cross)-compile
works as intended?
/Marthin
 
> -----Original Message-----
> From:  [mailto:owner-erlang-
> ] On Behalf Of Mikael Pettersson
> Sent: 29 November 2005 15:29
> To: Marthin Laubscher
> Cc: 
> Subject: RE: choice of gcc version for Erlang on ARM/XScale/PXA
> 
> Marthin Laubscher writes:
>  > It was all cross-compiled. I know erlc works on the gumstix itself, but
> I'm
>  > pretty sure /lib/x/ebin/*.beam files were generated in the cross-
> compiling
>  > environment. After fixing the float library problem, I didn't pick up
> any
>  > other issues, but now I'm worried about what is going to still go
> wrong. Do
>  > you think I should I leave the .beam files or try to get a version of
> GNU
>  > make running on the gumstix and build them all there again. I've
> trimmed the
>  > system to a minimum so making the .beam files will involve fiddling
> with the
>  > makefiles again.
> 
> No, leave the .beam files alone. Rebuilding them on your gumstix will
> almost certainly trigger the bug. I'm away from my ARM box so I can't
> produce a nice test case right now, but the bug broke an integer shift
> operation so that an 8-bit downshift of a bignum became an 8-bit upshift
> instead. See what "16#001000000000 bsr 8." evaluates to in the shell.
> 
>  > Are you working on gumstix or another ARM/XScale/PXA implementation?
> 
> I'm using an XScale, actually an IXP420. I looked at the gumstix, but
> it seemed to lack any disk I/O facilities, even USB2.0 based ones,
> and given that limitation it seemed a bit overpriced.
> 
>  > My
>  > gumstix app needs good float performance so I a little worried about
> running
>  > without fpu. I'd love to learn about equally small alternatives that do
>  > include a fpu option.
> 
> No XScale/PXA to date has an FPU, so if you need good f.p. performance
> you should look elsewhere. www.arm.com does have cores with the VFP FPU,
> but I don't know where one can buy systems based on them.
> 
> /Mikael







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