Quick introduction to reverse engineering for beginners

xor ebp, ebx
not eax
mov DWORD PTR [edi], ebp
xor eax, ecx
mov ecx, DWORD PTR _out3$[esp+32]
xor eax, DWORD PTR [ecx]
pop edi
pop esi
xor eax, ebx
pop ebp
mov DWORD PTR [ecx], eax
pop ebx
add esp, 20 ; 00000014H
ret 0
_s1 ENDP
5 variables was allocated in local stack by compiler.
Now let’s try the same thing in 64-bit version of MSVC 2008:
a1$ = 56
a2$ = 64
a3$ = 72
a4$ = 80
x36$1$ = 88
a5$ = 88
a6$ = 96
out1$ = 104
out2$ = 112
out3$ = 120
out4$ = 128
s1 PROC
$LN3:
mov QWORD PTR [rsp+24], rbx
mov QWORD PTR [rsp+32], rbp
mov QWORD PTR [rsp+16], rdx
mov QWORD PTR [rsp+8], rcx
push rsi
push rdi
push r12
push r13
push r14
push r15
mov r15, QWORD PTR a5$[rsp]
mov rcx, QWORD PTR a6$[rsp]
mov rbp, r8
mov r10, r9
mov rax, r15
mov rdx, rbp
not rax
xor rdx, r9
not r10
mov r11, rax
and rax, r9
mov rsi, r10
mov QWORD PTR x36$1$[rsp], rax
108