cwd     ; convert word to doubleword

cdq     ; convert doubleword to quadword

        ; Doubles the size of the operand in register AX or EAX (depending on the          

          operand size) by means of sign extension and stores                                                        

        ; the result in registers DX:AX or EDX:EAX, respectively.

movzx     ; move with zero-extend

          ; Doubles the size of the operand in register AX or EAX (depending on

            the operand size) by means of sign extension and stores     

          ; the result in registers DX:AX or EDX:EAX, respectively.

movsx     ; move with sign-extension

          ; Copies the contents of the source operand (register or memory

            location) to the destination operand (register) and sign                        

          ; extends the value to 16 or 32 bits. The size of the converted value

            depends on the operand-size attribute.

cmp al,dl     ; set flags based on the comparison

jg label1     ; then jump based on the flags

instruction (destination<-source)

nibble: 4bits

byte: 8bits

word: 16bits

doubleword: 32bits

quadword: 64bits