Re: [Qemu-devel] [PATCH] Porting TCG to alpha platform

[Edgar E. Iglesias]

On Fri, Jan 29, 2010 at 09:04:58AM -0800, Richard Henderson wrote:
> On 01/28/2010 05:55 PM, identifier scorpio wrote:
> > Your code is more skilled and I learn a lot from it, but I haven't yet
> > recognized the key difference between your version and mine. In last
> > mail, you've said that "Mainly, tcg_target_long was used places that
> > could be holding HOST values, which means that the host values would
> > have been truncated to 32 bits.", and I can't fully understand it, may
> > you put it more clearly.
> 
> It was a mis-statement made while tired.  Of course tcg_target_long is 
> defined to int64_t when TCG_TARGET_REG_BITS == 64, so there was no 
> truncation to 32 bits.
> 
> Have you tested of any of the other embedded targets?  You may be able 
> to find the error with one of those easier than finding it emulating 
> full-scale Windows.  See the images at the bottom of the QEMU download page.

Hi,

Although I've never hacked on a TCG backend I'd still like to give some
advice.

>From experience when developing both the CRIS and the MicroBlaze ISA
translators I very much suggest getting something very stable to work
in linux-user before going further.

I used GCC's C torture tests and OpenSSL's bignum tests to verify the
ports. In particular, OpenSSL's bignum tests seem to excersice lot's of
cornercases.

If you pass those, you've come a long way. In general it's much easier
to debug a guest testcase (bntest, etc) that fails compared to huge
propretiary blob that fails (windows).

Just a suggestion, hope it helps.

Cheers,
Edgar