Re: [Qemu-devel] ARM: Adding Maverick FPU support

[Lennert Buytenhek]

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