Using ARM Cortex M:

Write an ARM Cortex M assembly function that returns a true (RO-1) if an ASCII character is a hex digit, otherwise return false (RO-0) Hex digits are 0x30 to 0x39 and 0x41 to 0x46 inclusive. The input character is passed as a value in RO, and the return parameter is returned in RO This will get you started: SHex: CMP R0 , #0x30 BLO no CMP RO, #0x31 BLS yes :You write this part MOV R0 , #0 B done MOV R0 , #1 no : yes : done: B LX ; return