assemble under nios2

Altera_Forum · ‎12-01-2006

Hi all,

i write a program under nios2 using assemble lanauge, following is the source code

# include <linux/module.h># include <linux/kernel.h>

void print(void)

{

printk("function print\n");

}

typedef void(*pointer)(void);

ulong code[3];

void jump(void)

{

__asm__("movia r12, print");

__asm__("jmp r12");

}

int __init init_filter(void)

{

jump();

}

void __exit exit_filter(void)

{

}

module_init(init_filter);

module_exit(exit_filter);

this can work well, but if i change the function init_filter as bellow, the system will reboot,

int __init init_filter(void)

{

pointer p;

code[0]=0x03000034;

code[1]=0x63000004;

code[2]=0x6000683a;

p = (pointer)code;

p();

}

code[0]~code[2] is the hex value that i get from nios2-elf-objdump according to two assemble sentences.

how should i do?

thanks a lot

Altera_Forum · ‎12-01-2006

Hi qiunuoku,

I'm assuming that 'code' is a valid pointer ... and the opcodes are correct. That said, if you're

using a data cache, you need to flush the region you modified with the new instructions.

Then if you're using and instruction cache, you need invalidate the appropiate region as well.

Otherwise, you will likely be executing stale bits rather than your copied code.

Regards,

--Scott

Altera_Forum · ‎12-04-2006

to Scott

thanks