push ebp enter Imm, 0 mov ebp, esp -> nop add esp, -Imm nop
push ebp enter -Imm, 0 mov ebp, esp -> nop add esp, Imm nop
mov esp, ebp -> leave pop ebp nop
mov Reg1, Reg2 -> push Reg1 / pop Reg2
xor Reg, Reg -> sub Reg, Reg sub Reg, Reg -> xor Reg, Reg
or Reg, Reg -> test Reg, Reg and Reg, Reg -> or Reg, Reg test Reg, Reg -> and Reg, Reg
add Reg, Imm <-> sub Reg, -Imm sub Reg, Imm <-> add Reg, -Imm
mov Reg, fs:[0] -> xor Reg, Reg / mov Reg, fs:[Reg]
mov EAX, fs:[0] -> xor EAX, EAX / mov EAX, fs:[EAX]
xor Reg, Reg / dec Reg -> or Reg, -1
xor/sub Reg, Reg / mov Reg_8, Reg1_8 -> movzx Reg, Reg1_8
Inverse All (ROL,ROR,RCL,RCR,SHL/SHA,SHR,SAR,ADD,SUB,AND,OR,XOR,MOV,CMP Reg1, Reg2)
It also contains a shrinker of instructions, for example add eax, 10 followed by sub eax, 20 will become add eax, -10 or mov Reg, 10 followed by add Reg, 10 will become mov eax, 20. This is not really useful for PE files since they are already optimized.