Re: [Qemu-devel] MIPS exception number limits?

[Johnson, Eric]

> -----Original Message-----
> From: Richard Henderson [mailto:address@hidden On Behalf Of Richard
> Henderson
> Sent: Tuesday, November 27, 2012 1:19 PM
> To: Johnson, Eric
> Cc: "陳韋任 (Wei-Ren Chen)"; address@hidden
> Subject: Re: [Qemu-devel] MIPS exception number limits?
> 
> On 11/26/2012 09:25 PM, Johnson, Eric wrote:
> > So basically the SC and SCD instructions for user-mode QEMU are
> implemented with a "dummy" exception.  Since it is not a real exception,
> it is not reported in the QEMU log file as an exception.
> 
> I'm not certain that's a helpful distinction to make when it comes to
> debugging qemu.
> 
> 
> r~

It may not be a helpful distinction.

The under 0x100 check has been there since 2005 which is long before I looked 
at any QEMU code.  I was describing the code as it exists based on deductions 
from looking at the code.  I should have made that clear that my summary.

My first draft of a response I described the steps I did (I.E. vim op_helper.c, 
grep EXCP *.h, gitk op_helper.c, grep EXCP_SC *, vim translate.c) to get to the 
conclusions I made.  When I read it seemed like it might be interpreted as 
condescending which was not my intent.

In the original reply I also meant to say "removing the '#if 1' is fine with 
me."

/If/ the under 0x100 check remains, I would advocate using EXCP_SC instead of a 
magic constant.

-Eric