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Goto a specific Address in C

How can I JMP to a specific address in C?

I want to use

goto 0x10080000

This is not working, is there other way I can change the address of Program Counter??

like image 518
Rgarg Avatar asked Oct 04 '13 04:10

Rgarg


3 Answers

You can cast the address to a function pointer and then jump into:

((void (*)(void))0x10008000)();

To make it a bit more clear:

typedef void (*func_t)(void);
...
((func_t)0x10008000)();

But this is a function, the compiler will emit a branch instruction that expect to return (then is up to you to make your function return or not). Also notice that the compiler will produce a code that expect to find a C function at the given address, about how the function arguments are given and returned.

If you need to emit a branch instruction without return you need to use inline assembly.

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Alex Avatar answered Oct 08 '22 07:10

Alex


In GCC you can use computed goto. I didn't try it myself, but it should work like this:

void *address = 0x10080000;
...
goto *address;
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qrdl Avatar answered Oct 08 '22 09:10

qrdl


Inline assembly instruction should work too:

asm("jump 0x10080000");

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Rgarg Avatar answered Oct 08 '22 09:10

Rgarg