- Integers are represented as a string of bits (binary digits)
Endianity
Big Endian
- Most significant place value at left
- Three-hundred twenty-one as
321
Little Endian
- Most significant place value at right
- Three-hundred twenty-one or
123.
Unsigned Integers
- Number of bits used (width) determines the numbers that can be encoded 2n.
Signed Integers
There are four methods for signed integer representation
Two’s Complement
To negate a number:
- Invert all the bits in a number
- Add 1
This approach only has one representation of 0
The range for this is from -2n to 2n-1 - 1
Arithmetic
Multiplication
Multiplying a number by any factor of 2 (any even number) is done with Bitwise Shift Left.
-
This can work for odd numbers as well by factorizing and grouping then adding
1
Division
Dividing is done with Bitwise Shift Right. It’s integer division (no float representation) so it’s rounded down (approximated).