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

[Libo Zhou]

> I would start by using the QEMU gdbstub to connect a
> MIPS-aware gdb. Then when the SIGILL arrives you can see
> what instruction the guest program was trying to execute.

Just tried it and found something interesting.
I connected gdb-multiarch to QEMU gdbstub. gdb-multiarch's architecture was set 
to mips:3000 automatically (and Wikipedia says r3k uses MIPS-I).

When I did 'layout asm', and compared the instructions displayed against test.s 
generated by my mipsel-linux-unknown-gcc, they appeared to be a little bit 
different.

The 'store word' instruction in test.s is shown as a hex '0x7f......(don't 
remember the rest)';
'load word' is shown as '0x5f......';
'load immediate' is seen as 'addi';
'j' as 'jr';

When I single-stepped the instructions, the SIGILL was thrown immediately after 
the first unrecognized 0x7f......, which is supposed to be a store word (sw).
 
Hence, can I conclude that MIPS-I is not implemented in QEMU out of the box?