Substitutes for x86 assembly 'call' instruction?

Question

What are some alternatives to the x86 call instruction? Maybe something like a push of the return address then a jump?

Also is their a command for obtaining the current position in memory?

Answer 1

The call instruction actually does this for you. For example call my_func would do something like:

push ret_address
jmp my_func

A subsequent ret call would just use the address you just pushed to jmp back in a sense. Is there a specific reason that you don't want to use call or is it not available for you? For current position in memory you can try to read the eip register (can't write to it).

Answer 2

You can just push a dword value and jmp to the procedure. The push would be the return address :

push return_address (push eax if address in eax)
jmp call_address

Remember to also push arguments if they exist for that particular call.

What do you mean by current position in memory ? I suppose that you mean the current instruction pointer. You cannot get that directly, but you can use a seh handler(structured exception handler) to get that value upon causing a handled exception.