Module 0217: Adding in assembly language

Tak Auyeung, Ph.D.

February 16, 2010
1 About this module
2 Isn’t that trivial?
3 Binary adding revisited
 3.1 Revisiting the add rules
 3.2 Bit operators
 3.3 Back to adding
 3.4 Half adding and full adding
 3.5 The last carry
 3.6 Is the result zero?
4 What about signed numbers?
 4.1 Two’s complement
 4.2 What exactly is a negative number?
 4.3 Is two’s complement a good fit?
 4.4 What does 11012 represent?
 4.5 Ranges of numbers
5 The add instruction
6 Flags
 6.1 C-flag
 6.2 Z-flag
 6.3 S-flag
 6.4 O-flag
7 How do I see the flags?
8 Add with carry