Category "instruction-encoding"

How do you understand 'REX.W + B8+ rd io' form for x86-64 assembly?

I was originally trying to generate the bytes for an immediate move into a 64 bit register.The specific operation I wanted was mov rdi, 0x1337 Using https://ww

Null bytes in shellcode? Why does mov eax,1 machine code have bytes that are 00?

Going through the shellcode article on wikipedia, it gives an example as follows: B8 01000000 MOV EAX,1 // Set the register EAX to 0x000000001 To