AOA - chapter 2: Data Representation

1.Decimal -> Binary:
1) Power of 2 down to 2**0
2) even/odd - divided by two algorithm
- first step: even - 0, odd -1
- second step: * / 2: quotient even: prefix 0
quotient odd: prefix 1
go back to second step
2. Low order -> least significant bit
High order -> most significant bit
3.
-Bit
-Nibble represents: 4 bits
a) Binary coded decimal numbers
b) Hexadecimal numbers
-Byte: 8bits
a)smallest addressable datum
b)byte values require two hexadecimal digits
c)usage:
- signed or unsigned numbers (-128..127, 0..255)
- ASCII character codes: 128 for ASCII characters, remaining 128 for European characters, graphic symbols, Greek letters, math symbols.
-Word:
a)Usage:
- unsigned and signed integer values
- unicode characters
-Double Word
a)Usage:
- unsigned and signed integer values
- pointer variable

4.Hexadecimal numbering system:
a)Advantage:
- compact
- simple to convert to binary and vice versa

5.Logical operation
a)Truth table
b)AND -> used to force a zero result
c)OR -> used to force a one result
b)XOR -> more closer to the english meaning of 'or'
-> used to invert a bit.

c) OPERATION (source, dest)
=> dest = dest OPERATION src

6. Two's complement notation
- High order bit is a sign bit: 0 - positive, 1-negative

7. Positive number - stored as standard binary value
8. Negative number - stored in the two's complement form
a)