Register EDI holds the bit offset …

software | Windows | EDI: The Destination Index Every loop that generates data must store the result in memory, and doing so requires a moving pointer. The destination index, EDI, is that pointer. The destination index holds the implied write address of all string operations. The most useful string instruction, remarkably enough, is the seldom-used …

16 bits into the segment register…(GS)

software | Windows | These instructions read a full pointer from memory and store it in the selected segment register:register pair. The full pointer loads 16 bits into the segment register SS, DS, ES, FS, or GS source : http://pdos.csail.mit.edu/6.828/2008/readings/i386/LGS.htm software |GNU/Linux| (gdb) info registers rax 0xfffffffffffffdfc -516 rbx 0x5dc 1500 rcx 0xffffffffffffffff -1 rdx …