[Qemu-devel] Running QEMU for Microblaze

[Ormaetxea Xabier]

Hello!

I'm trying to run QEMU-Microblaze (Little-endian) with a standalone app in some 
different ways, but none of them works for me:


1)      I have created my own .DTB from my system design (.HDF), just a 
microblaze connected to the Uartlite AXI, leds, interrupt controller, and a 
gpio. Using the board support package I've made a simple c-based program (at 
the end of the message):

Run it with ./qemu-system-microblazeel -M microblaze-fdt-plnx -dtb 
system-top.dtb -kernel fibonacci.elf (-s -S)         #(-s -S just to debug it)

Invalid MicroBlaze version number: (null)           #Don't think it's a problem
Bar ram offset 9000528f
Aborted (core dumped)


2)      I use a mb.dtb that I found on the internet. Same c-based program. Run 
it with the debugger:

./qemu-system-microblazeel -M microblaze-fdt-plnx -dtb mb.dtb -kernel 
fibonacci.elf (-s -S)

Lets my debug it (doesn't fail booting), but in the first step:
Bad ram pointer

I suppose this isn't my option cause the .dtb is created for another 
microblaze-based design.


3)      I use the same design (.HDF), but run it for the Spartan 3a dsp 1800 
option:

./qemu-system-microblazeel -kernel fibonacci.elf (-s -S)

Runs "properly" -> I mean properly because I can follow on the debugger that 
the steps are correctly made:
_start -> _start1 -> main -> fibonacci -> xil_printf -> xil_printf ... -> 
xil_printf -> _exit

But doesn't print nothing. And doesn't write in memory as asked (*addrPtr = 
0x150) :
In the qemu shell:
(qemu) x 0xC0000000
C0000000: 0x00000000        #When it should be 0x00000150


4)      Modifying my system design to be similar to the Spartan board design:
MEMORY_BASEADDR 0x90000000
FLASH_BASEADDR 0xa0000000
INTC_BASEADDR 0x81800000
TIMER_BASEADDR 0x83c00000
UARTLITE_BASEADDR 0x84000000
ETHLITE_BASEADDR 0x81000000
                I get exactly the same result as in the (3) case.

So here they go my questions:

-          Am I doing it right? Is this the method of running a standalone 
program over a microblaze?

-          How can I make the program print something?

-          Im not sure if the problem is that it doesn't write on memory, or I 
am the one who fails reading it from the shell, because if I change the writing 
position to (0x84000008, uart status position) I get the error (qemu: hardware 
error: write to UART STATUS?) -> that means im writing (or trying, at least). 
How can I write on memory (and read after it, so I know it works)?

Thank you in advance! Really appreciate your Job! (I'm sorry if my problem it's 
a simple one, I'm new at it)

#include <stdio.h>
#include "platform.h"
#include "xil_printf.h"

void fibonacci(int d){
       u32 a=1;
       u32 b=0;
       u32 em=0;
       u32 *addrPtr = 0xC0000000;

for(int num=0; num<d; num++){
       for(int i=0; i<a; i++){
       }
       for(int c=0; c<b; c++){
       }
       em = a+b;
       xil_printf(em);
       *addrPtr = 0x150;
       addrPtr+=1;
       b=a;
       a=em;
       }
}


int main()
{
    init_platform();
    int i=35;
    fibonacci(i);
    cleanup_platform();
    return 0;
}