[LinuxBIOS] General question abouts jumps in machine code

Stefan Reinauer stepan at coresystems.de
Fri Jun 29 20:17:06 CEST 2007

* Shadravan Fontanov <shadravan_f at yahoo.com> [070629 19:03]:
> Exactly 64 times 0x90, fine... The next code after the last 0x90 is 0xe9. Look
> at "Intel Architecture Software Developers Manual Vol2" tells: its jump
> instruction, the next two bytes (bd ff) specify the relative address to jump.
> bdff must be  in second complement and  represent  minus 4201. But offset 4201
> does not jumps to the start of the NOP sequence, it jumps to a very smaller
> address...

The number is little endian, so it is 0xffbd, which is 2 bytes short of
0xffc0, which is -64 in 16bit hex.


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