ReadHex PROC

   Reads a 32-bit hexadecimal integer from standard input, stopping when the Enter key is pressed.
   No error checking performed for bad digits or excess digits.
   You can use both uppercase and lowercase letters for the digits A through F.
   A maximum of eight digits may be entered.
   Leading spaces are not permitted.

Call args:  None

Return arg: EAX = binary integer value

Example:

.data
hexNum DWORD ?

.code
       call ReadHex
       mov  hexNum,eax