mov ax, byte ptr [ds:tempByte] ;assembler will generate an error - operands don't match
mov al, word ptr [ds:tempWord] ;assembler will generate an error - operands don't match
mov ax, word ptr [ds:tempByte] ;assembler will allow this even though the intended data size is wrong
mov al, byte ptr [ds:tempWord] ;assembler will allow this even though the intended data size is wrong