Assembly Language Questions

Write a single instruction using 16-bit operands that clears the low 8 bits of AX and does not change the high 8 bits. Write a single instruction that converts an uppercase character in AL to lowercase, but does not change it if it is already lowercase. Write a single instruction that converts an ASCII digit in AL to its corresponding binary value, but if it is already a binary value (0 to 9), doesn't change it