[Qemu-devel] Need help: Save word (sw) and load word (lw) not working

[Qemu-devel] Need help: Save word (sw) and load word (lw) not working

[Philip Loh]

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Hello,

I'm new to QEMU development and am attempting to write code for a new board
and system. I modeled the code after the code in the target-microblaze
folder, but removed the dependency on the petalogix board and instead made
it require the code from my board. At this point, it can boot and execute a
binary file with no issues until it attempts to do a save word / load word.
The dump for the binary is as follows:
   0:    20200040     addi    r1, r0, 64
   4:    20400030     addi    r2, r0, 48
   8:    20600020     addi    r3, r0, 32
   c:    d8411000     sw    r2, r1, r2
  10:    d8611800     sw    r3, r1, r3
  14:    c8811000     lw    r4, r1, r2
  18:    c8a11000     lw    r5, r1, r3

One would expect the sw and lw components (highlighted in yellow) to save r2
to *(r1+r2) and then load it back to r4, and save r3 to *(r1+r3) and then
load it back to r5. However, r4 and r5 are both 0 at the end. I don't know
how to verify what is at *(r1+r2) or *(r1+r3) because when I attempt to "x *
address*" in a remote desktop viewer, all I see are zeroes beyond x 18.
Would anyone know what went wrong? Much thanks!

-- 
Philip Z Loh,
Intern at Aeste Works (M),
Candidate for Bachelor of Science in Engineering: Computing.

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Re: [Qemu-devel] Need help: Save word (sw) and load word (lw) not working

[Stefan Hajnoczi]

On Mon, Jun 27, 2011 at 8:37 AM, Philip Loh <philip.loh@aeste.net> wrote:
> I'm new to QEMU development and am attempting to write code for a new board
> and system. I modeled the code after the code in the target-microblaze
> folder, but removed the dependency on the petalogix board and instead made
> it require the code from my board. At this point, it can boot and execute a
> binary file with no issues until it attempts to do a save word / load word.
> The dump for the binary is as follows:
>    0:    20200040     addi    r1, r0, 64
>    4:    20400030     addi    r2, r0, 48
>    8:    20600020     addi    r3, r0, 32
>    c:    d8411000     sw    r2, r1, r2
>   10:    d8611800     sw    r3, r1, r3
>   14:    c8811000     lw    r4, r1, r2
>   18:    c8a11000     lw    r5, r1, r3
>
> One would expect the sw and lw components (highlighted in yellow) to save r2
> to *(r1+r2) and then load it back to r4, and save r3 to *(r1+r3) and then
> load it back to r5. However, r4 and r5 are both 0 at the end. I don't know
> how to verify what is at *(r1+r2) or *(r1+r3) because when I attempt to "x
> address" in a remote desktop viewer, all I see are zeroes beyond x 18. Would
> anyone know what went wrong? Much thanks!

If you are able to post a link to a git repo that might help.  Seeing
how you set up the board and added RAM would be important.

Stefan

Re: [Qemu-devel] Need help: Save word (sw) and load word (lw) not working

[Philip Loh]

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Resolved: I accidentally compiled an executable that had a different memory
map than the board's memory map.

Thanks though!

On 27 June 2011 16:17, Stefan Hajnoczi <stefanha@gmail.com> wrote:

> On Mon, Jun 27, 2011 at 8:37 AM, Philip Loh <philip.loh@aeste.net> wrote:
> > I'm new to QEMU development and am attempting to write code for a new
> board
> > and system. I modeled the code after the code in the target-microblaze
> > folder, but removed the dependency on the petalogix board and instead
> made
> > it require the code from my board. At this point, it can boot and execute
> a
> > binary file with no issues until it attempts to do a save word / load
> word.
> > The dump for the binary is as follows:
> >    0:    20200040     addi    r1, r0, 64
> >    4:    20400030     addi    r2, r0, 48
> >    8:    20600020     addi    r3, r0, 32
> >    c:    d8411000     sw    r2, r1, r2
> >   10:    d8611800     sw    r3, r1, r3
> >   14:    c8811000     lw    r4, r1, r2
> >   18:    c8a11000     lw    r5, r1, r3
> >
> > One would expect the sw and lw components (highlighted in yellow) to save
> r2
> > to *(r1+r2) and then load it back to r4, and save r3 to *(r1+r3) and then
> > load it back to r5. However, r4 and r5 are both 0 at the end. I don't
> know
> > how to verify what is at *(r1+r2) or *(r1+r3) because when I attempt to
> "x
> > address" in a remote desktop viewer, all I see are zeroes beyond x 18.
> Would
> > anyone know what went wrong? Much thanks!
>
> If you are able to post a link to a git repo that might help.  Seeing
> how you set up the board and added RAM would be important.
>
> Stefan
>



-- 
Philip Z Loh,
Intern at Aeste Works (M),
Candidate for Bachelor of Science in Engineering: Computing.

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