[Qemu-devel] What is cpu_A0 in target-i386/translate.c

[Qemu-devel] What is cpu_A0 in target-i386/translate.c

[Steven]

Hi,
I would like to trace the guest physical address of the load
instructions from the guest. I thought the cpu_A0 is the memory
address to be accessed. However, when I print out the value of cpu_A0,
like

static inline void gen_op_ld_v(int idx, TCGv t0, TCGv a0)
{
     int mem_index = (idx >> 2) - 1;
+    qemu_log("cpu_A0: %llu\n", a0.i64);
     switch(idx & 3) {
     case 0:
         tcg_gen_qemu_ld8u(t0, a0, mem_index);
}

I saw the value of cpu_A0 is always 23 (in decimal). Is there anything
about this? Or does cpu_A0 have a different meaning? Thanks.

steven

Re: [Qemu-devel] What is cpu_A0 in target-i386/translate.c

[Andreas Färber]

Hi,

Am 15.08.2012 08:33, schrieb Steven:
> I would like to trace the guest physical address of the load
> instructions from the guest. I thought the cpu_A0 is the memory
> address to be accessed. However, when I print out the value of cpu_A0,
> like
> 
> static inline void gen_op_ld_v(int idx, TCGv t0, TCGv a0)
> {
>      int mem_index = (idx >> 2) - 1;
> +    qemu_log("cpu_A0: %llu\n", a0.i64);
>      switch(idx & 3) {
>      case 0:
>          tcg_gen_qemu_ld8u(t0, a0, mem_index);
> }
> 
> I saw the value of cpu_A0 is always 23 (in decimal). Is there anything
> about this? Or does cpu_A0 have a different meaning?

A TCGv is the identifier of a TCG variable at translation time, which in
turn at runtime (in a register or memory) contains the value.

Andreas

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg