Calculation Method of jmp offset address

Calculation of jmp distance of E9: distance = destination address-(current address + 5) (plus 5 is because the JMP command occupies a total of 5 words, actually the destination address minus the end address of the JMP command, that is, the current address + 5
If the target address is f1e0b63e
The current address is 8093c6d8.
Distance = f1e0b63e-8093c6d8-5 = 714cef61
Jmp is
Current address current encoding assembly instruction
8093c6d8 e961ef4c71 (written backwards) jmp f1e0b63e

Encoded in C ++

1. # Include "stdafx. h"
2. # Include <iostream>
3. Using namespace std;
5. Int _ tmain (int argc, _ TCHAR * argv [])
6. {
7. Unsigned long a = 0xf1e0b63e;
8. Unsigned long B = 0x8093c6d8;
9. Unsigned c = a-b-5;
10. Int d [4];
11. For (INT I = 0; I <4; I ++)
12. {
13. D [I] = 0;
14. D [I] + = C % 16;
15. C = C/16;
16. D [I] + = C % 16*16;
17. C = C/16;
18. Cout
19. }
20. Return 0;
21. }
22. // E9 d [0] d [1] d [2] d [3] Is e961ef4c71

If the destination address is smaller than the current address, the distance is-5