Running .elf file on LEON3 processor using QEMU

Question

lately I have been trying to execute code on Leon3 processor using qemu. My code looks like this:

#include <stdio.h>
#include <stdint.h>


int main(void) {
    
    
    int a,b,c,d,e;  
    printf("hello world!");
   
    
    
    if(a){
        a++;
    };
    
    if(b){
        b++;
    };
    
    if(c){
        c++;
    };
    
    if(d){
        d++;
    };
    
    
    if(e){
        e++;
    };
    
    
    while(1){
    }
    
    
    
    
   
    return 0;
}

so it's a pretty simple program. I start Qemu with following command:qemu-system-sparc.exe -nographic -M leon3_generic -m 64M -kernel testapp.elf

but I don't get any outupt. Qemu seems to start and immidiately quits, not even hanging on infinite loop. Trying to debug leads to crash(?) with following code: qemu-system-sparc.exe: QEMU: Terminated via GDBstub

I think that maybe i don't undesrtand something about qemu, but I cannot find any help regarding running .elf files.

Maybe anyone have done this and can help me?

Answer 1

OK, so I have found a way to do this.

As Peter mentioned in the comments: Qemu needs "something" more than bare metal .elf file.

I have found that there is a tool MKPROM2 provided by Cobham-Gaisler that takes an .elf file and creates a ROM image that later can be loaded to Qemu with -kernel option.

The ROM image is different from bare metal .elf in a way that ROM image contains some initalization code that allows to run the program we initally wanted to execute.

So finally all that has to be done is running: mkprom2 -freq 20 -romres testapp.elf

This outputs prom.out file that can be loaded to qemu.