How can you pull a value from a register?

2
votes

I'm trying to figure out how to pull a register value from an ASM instruction and into a variable in C++.

For example: MOV DWORD PTR DS:[ESI],EDI

(Assuming value EDI holds is an int) int Value = EDI;

1
c++assemblyx86
Of course, by the time your code executes, the value in the registers may have changed. What are you really trying to do? Perhaps you should be getting it from a context record or something. - Raymond Chen

1 Answers

5
votes

Depends on your compiler. Search for "inline assembly" and the compiler you use. For example with VC++

   int32_t x;
   _asm mov x, eax;

(might be __asm). GNU uses different syntax