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Re: [Qemu-devel] ARM: Adding Maverick FPU support
From: |
Lennert Buytenhek |
Subject: |
Re: [Qemu-devel] ARM: Adding Maverick FPU support |
Date: |
Mon, 7 Feb 2005 13:55:20 +0100 |
User-agent: |
Mutt/1.4.1i |
On Mon, Feb 07, 2005 at 01:32:04PM +0100, Fabrice Bellard wrote:
> >Note that that FPA is implemented differently. I uses the same emulator as
> >the linux kernel, hooked up to the undefined instruction interrupt. I
> >wouldn't advise doing this as performance is really awful. It's
> >approximately 2x slower than target soft-float, and I guess about 20x
> >slower than a native implementation.
>
> Just to give more information, the idea was not to integrate the FPA
> emulation in the CPU itself because I believed it was mostly implemented
> as a software FPU. The real directory of FPA should be
> qemu/linux-user/arm/nwfpe and _not_ qemu/target-arm/nwfpe.
This makes sense, because if you do ARM system emulation, your emulated
kernel will handle floating point emulation.
> Now if real ARM FPUs are implemented, I agree they should go in op.c and
> translate.c (an helper.c can be added too). There must be a way to
> disable it so that the exact emulated ARM CPU core can be selected with
> a command line option.
How about an option for disabling all ARMv5(TE) instructions?
--L