[kaffe] [PATCH] JIT on arm

[Steven Newbury]

--- Kiyo Inaba <inaba at src.ricoh.co.jp> wrote:

> Kiyo Inaba wrote:
> >>just now. I will invoke another configure run (on this emulated machine
> >>it may take one hour) with '--with-libffi' options.
> >
> >Even with '--with-libffi' option, arm/jit with gcc-4.1 does not work.
> >It got same error message with sysdepCallMethod version.
> 
> While playing with jit3 (for arm), I surfed the net to find some info
> of QEMU for Xscale (official 0.9.0 does not have it, but patch is
> available), and found interesting story for ABI.
> 
> According to
>   http://wiki.debian.org/ArmEabiPort
> gcc for arm now can support two different ABI, and I have no idea
> which becomes default for gcc-4.1. This is another thing what I have
> to check.
It depends how the toolchain was configured.  If it was built to target
arm-*-linux-gnueabi then it is (Linux) EABI, if the target is arm-*-linux-gnu
then it is the old apcs-gnu API.  An ARM compiler can produce code for each
with appropriate -mabi= flags as you use below but the support libraries will
typically only be for the target.  A multi-lib build is possible too though.
> 
> Of course, Steven or Sascha mentioned something for EABI, but when
> I first read them, I just think this is only for the floating point.
FPA is no longer available with the EABI so there is a big difference for
floating point since it was assumed as part of the old ABI despite very few
hardware implementations.  Modern FP units on ARM core based CPUs are not
compatible with FPA anyway and so the FP units were going unused in generic
code while the kernel was having to trap FPA instructions and emulate the FPA. 
It was a major reason for adopting EABI.

> 
> After the build for jit3, I will invoke another build with explicitly
> specify '-mabi=apcs-gnu -mfpu=fpa' and check the result. As several of
> you may know, QEMU emulated arm is not first enough for me to do two
> build job at one time ;-)
> 
> Kiyo
> P.S. BTW, I still use 'jikes' on this machine because it slighly
>      shortens my build time ;-)
> 
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> 


Steve


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