[Qemu-devel] Re: singlestep and sparc32

[Blue Swirl]

On 4/19/10, Artyom Tarasenko <address@hidden> wrote:
> is -single-step option supposed to work under qemu-system-sparc? Or is
>  it only for non-pipelined CPUs?

I've never used it.

>  I get pretty strange results: some addresses seem to be executed
>  twice, and then qemu hangs on the last nop:

One possibility is that we don't generate any code at all for nops
(sethi x, %g0). If you delete the "if (rd)" check in translate.c:1784,
does it help?

>  --------------
>  IN:
>  0x00000000:  b  0xb788
>  --------------
>  IN:
>  0x00000004:  rd  %psr, %l0
>  --------------
>  IN:
>  0x00000004:  rd  %psr, %l0
>  --------------
>  IN:
>  0x00000008:  nop
>  --------------
>  IN:
>  0x00000008:  nop
>  --------------
>  IN:
>  0x0000000c:  nop
>  --------------
>  IN:
>  0x0000000c:  nop
>
>  ... skipped ...
>
>  IN:
>  0x7000a58c:  bg  0x7000a588
>  --------------
>  IN:
>  0x7000a590:  nop
>  --------------
>  IN:
>  0x7000a590:  nop
>  --------------
>  IN:
>  0x7000a594:  b  0x7000a570
>  --------------
>  IN:
>  0x7000a594:  b  0x7000a570
>  --------------
>  IN:
>  0x7000a578:  be  0x7000a59c
>  --------------
>  IN:
>  0x7000a580:  stba  %l1, [ %l0 ] #ASI_M_BYPASS
>  --------------
>  IN:
>  0x7000a588:  deccc  %l2
>  --------------
>  IN:
>  0x7000a594:  b  0x7000a570
>  --------------
>  IN:
>  0x7000a590:  nop
>
>  ^^^^^^^^^^^ That's the end
>
>  Without -singlestep it seems to work better:
>
>
>  0x7000a588:  deccc  %l2
>  0x7000a58c:  bg  0x7000a588
>  0x7000a590:  nop
>
>  --------------
>  IN:
>  0x7000a594:  b  0x7000a570
>  0x7000a598:  inc  %l4
>
>  --------------
>  IN:
>  0x7000a570:  lduba  [ %l4 ] #ASI_M_KERNELTXT, %l1
>  0x7000a574:  cmp  %l1, 0xff
>  0x7000a578:  be  0x7000a59c
>  ... and so on ...
>
>
>
>  --
>  Regards,
>  Artyom Tarasenko
>
>  solaris/sparc under qemu blog: http://tyom.blogspot.com/
>