Atari XL - Page 241

Numbering Systems
01100100
11001110
1 00110010
The result is binary 50 - the method worked.
229
Notice that a carry was generated, indicating that
the answer is positive. A consequence of using bit 7
as a sign bit is that the range of numbers we can
represent with an 8-bit number is restricted to
-128 to + 127
HEXADECIMAL
Manipulating numbers in binary is a lot easier for
a
computer than it is for a human, and one way in
which binary numbers can be made more digestible
is by representing them in hexadecimal notation,
or hex.
Hex is a system of counting in base 16, using the
symbols 0 to 9 and A to F as follows
DECIMAL 0 1 ••• 9 10 11 ••• 15 16 17
HEX 0 1 ••• 9A B... F 10 11
Thus FF (hex) represents 255 (decimal) and
11111111(binary).
You will frequently encounter references to hex,
usually as memory addresses, because it is so
convenient. (Which of these is easiest to recognise? .
1111111111111111 or 65535 or #FFFF).