Hexadecimal self-defining term
A hexadecimal self-defining term consists of hexadecimal digits enclosed in apostrophes and
preceded by the letter X; for example, X'C49' and X'00FF00FF00'.
Spaces within the value are allowed and ignored. They can be used between groups
of digits to improve readability, for example X'7F FF FF FF'.
Each hexadecimal digit is assembled as its 4 bit binary equivalent. Thus, a hexadecimal term used to represent an 8 bit mask consists of two hexadecimal digits.
The hexadecimal digits and their bit patterns are as follows:
0 - 0000 4 - 0100 8 - 1000 C - 1100
1 - 0001 5 - 0101 9 - 1001 D - 1101
2 - 0010 6 - 0110 A - 1010 E - 1110
3 - 0011 7 - 0111 B - 1011 F - 1111When used as an absolute term in an expression, a hexadecimal self-defining term has a negative value if the high-order bit is 1.