2-1
Central Processing Unit
The central processing unit (CPU) is responsible for controlling the flow of a
program and the processing of instructions. It performs arithmetic, Boolean-
logic, multiply, and shift operations. When performing signed math, the CPU
uses 2s-complement notation. This chapter describes the architecture, regis-
ters, and primary functions of the CPU.
Topic Page
2.1 CPU Architecture 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 CPU Registers 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Status Register ST0 2-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4 Status Register ST1 2-34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5 Program Flow 2-39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6 Multiply Operations 2-41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7 Shift Operations 2-44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 2