call and ret Mechanics

call foo   ; 1) push address of NEXT instruction (return addr)
           ; 2) RIP = foo         (jump into callee)

ret        ; 1) pop  [RSP] into RIP  (return to caller)
           ; 2) RSP = RSP + 8

• call writes the return address onto the stack.
• ret trusts whatever is at [RSP] and loads it into RIP — no validation.