Re: illegal hardware instruction during MIPS-I ELF linux useremulation

[Peter Maydell]

On Tue, 24 Sep 2019 at 02:10, Libo Zhou <address@hidden> wrote:
>
> > Can you run QEMU with some debugging options:
>
> > qemu-mipsel -d in_asm,exec,cpu,unimp,guest_errors,nochain -D debug.log
> > -singlestep test
>
> > and then put the resulting debug.log somewhere we can get it?
> > (it'll probably be quite large)
>
> The logging only shows this little information. It seems like only -d cpu 
> works for a short while.

> ----------------
> IN: main
> 0x00400094:  dmult.g    zero,sp,s8

I think "dmult.g" is an instruction specific to the Loongson CPU; it
is not in MIPS-I or even any of the other standard MIPS instruction
sets, which is why the default CPU for qemu-mipsel doesn't accept it
and is generating the SIGILL.

Something odd is going on here, because this doesn't seem to match
the disassembly of the test binary that you gave previously.

thanks
-- PMM