Integers in hexadecimal notation (i.e. hexadecimal integers) are formed using base 16, with the decimal digits 0 to 9 representing the values zero to nine and the letters A to F representing the values ten to fifteen. Integers in hexadecimal notation are prefixed with the $ symbol.
Here are some examples of valid hexadecimal integers
$64 $0 $FF $000aB4
The syntax for hexadecimal integers is as follows:
hexadecimal-integer = '$' hex-digit-sequence
hex-digit-sequence = hex-digit { hex-digit }
hex-digit = digit | 'a' | 'b' | 'c' | 'd' | 'e' | 'f'
digit = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'