Source program :

• LXI H, 4150 : Point to data
• MOV A, M : Get operand
• SUI 30 : convert to decimal
• CPI 0A : Check whether it is valid decimal number
• JC LOOP : yes, store result
• MVI A, FF : No, make result=FF
• LOOP: INX H
• MOV M, A
• HLT : (A) = (4151)

Note: The ASCII Code (American Standard Code for Information Interchange) is commonly used for communication. It is a seven bit code. In this code number 0 through 9 are represented as 30 through 39 respectively and letters A through Z are represented as 41H through 5AH. Therefore, by subtracting 30H we can convert an ASCII number into its decimal equivalent.