Re: [Qemu-devel] qemu on alpha

[Gabriele Gorla]

It seems I cannot send email to the mailing list from
my personal email account. Anyway... 
Here is what I discovered debugging the failure.
Is there anyone who can direct me to the next step?

thanks,
GG

> -------- Forwarded Message --------
> From: Gabriele Gorla <address@hidden>
> To: address@hidden
> Subject: Re: [Qemu-devel] qemu on alpha
> Date: Sat, 16 Feb 2008 22:11:21 -0800
> 
> Thiemo,
> thanks for your previous reply.
> I finally managed to compile qemu 0.9.1 on my
> machine (alpha ev68).
> 
> I had to add (as you suggested) the definition for
> GOTO_LABEL_PARAM:
> #define GOTO_LABEL_PARAM(n) asm volatile ("jmp
> "ASM_NAME(__op_gen_label)
> #n)
> 
> and I had to remove the -msmall-data option from the
> Makefile.target to
> make qemu link proprely.
> 
> Unfortunately I still can't run anything as qemu
> crashes very quickly
> when trying to execute the generated code.
> 
> Using gdb combined with qemu debug features I was
> able to narrow down
> the crash to the following instruction sequence:
> 
> ----------------
> IN:
> 0x400839f9:  pop    %ebx
> 0x400839fa:  add    $0x1104f,%ebx
> 0x40083a00:  xor    %eax,%eax
> 0x40083a02:  lea    0xfffffdec(%ebp),%edi
> 0x40083a08:  lea    0xfffeefa0(%ebx),%esi
> 0x40083a0e:  sub    0x84(%ebx),%esi
> 0x40083a14:  lea    0xfffffdbc(%ebp),%edx
> 0x40083a1a:  mov    %edx,0xfffffd90(%ebp)
> 0x40083a20:  lea    0xfffffdc0(%ebp),%ecx
> 0x40083a26:  mov    %ecx,0xfffffda0(%ebp)
> 0x40083a2c:  lea    0xfffffdc4(%ebp),%edx
> 0x40083a32:  mov    %edx,0xfffffd9c(%ebp)
> 0x40083a38:  lea    0xfffffdd4(%ebp),%ecx
> 0x40083a3e:  mov    %ecx,0xfffffd94(%ebp)
> 0x40083a44:  mov    %edi,%edx
> 0x40083a46:  movl   $0x0,(%edx,%eax,4)
> 0x40083a4d:  inc    %eax
> 0x40083a4e:  cmp    $0x61,%eax
> 0x40083a51:  jbe    0x40083a46
> 
> OUT: [size=936]
> 0x60589bb0: mov       s4,s2
> 0x60589bb4: zapnot s2,0xf,t0
> 0x60589bb8: ldl       s0,0(t0)
> 0x60589bbc: lda       s4,4(s4)
> 0x60589bc0: stl       s0,12(fp)
> 0x60589bc4: ldah gp,24606
> ...
> ...
> 0x60589e7c: ldah t0,0
> 0x60589e80: lda       t0,16(t0)
> 0x60589e84: mov       t0,t1
> 0x60589e88: stl       t1,48(fp)
> 0x60589e8c: ldl       t1,40(fp)
> 0x60589e90: ldl       t0,44(fp)
> 0x60589e94: addl t0,t1,t0
> 0x60589e98: cmpule t0,t1,t0
> 0x60589e9c: beq       t0,0x60589ea8
> 0x60589ea0: lda       t12,-22256(gp)
> 0x60589ea4: br        0x6071d244     <---- branch to
> uninitialized memory
> 0x60589ea8: ldah gp,24606
> 0x60589eac: lda       gp,-12160(gp)
> 0x60589eb0: ldah t0,24613
> 0x60589eb4: lda       t0,-25936(t0)
> ...
> ...
> 
> given the original instruction sequence I am a bit
> puzzled about the
> source of the offending branch instruction in the
> generated code.
> 
> do you have any suggestion on how to proceed?
> 
> thank,
> GG
> 


      
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