Categories of processor registers.
1.2 Define the two main categories of processor registers.
1.3 In general terms, what are the four distinct actions that a machine instruction can specify?
1.4 What is an interrupt?
1.5 How are multiple interrupts dealt with?
1.10 In general, what are the strategies for exploiting spatial locality and temporal locality?
Problems (10 points each)
1.2 The program execution of Figure 1.4 is described in the text using six steps. Expand this
description to show the use of the MAR and MBR.
1.3 Consider a hypothetical 32-bit microprocessor having 32-bit instructions composed of two
fields. The first byte contains the opcode and the remainder an immediate operand or an
operand address.
a. What is the maximum directly addressable memory capacity (in bytes)?
b. Discuss the impact on the system speed if the microprocessor bus has
1. a 32-bit local address bus and a 16-bit local data bus, or
2. a 16-bit local address bus and a 16-bit local data bus.
c. How many bits are needed for the program counter and the instruction register?
Sample Solution
Processor registers are a type of processor memory that temporarily holds data and instructions. They are located on the processor chip and provide high-speed access to frequently used information, allowing the processor to quickly retrieve the data it needs (Lazarin & Paraskevopolous, 2009). Registers can be divided into two main categories: general purpose registers and special purpose registers.
General purpose registers are designed for multiple uses. These include storing addresses of instructions, storing intermediate results during computations or calculations, as well as for passing parameters between subprograms (Lazarin & Paraskevopolous, 2009). Examples of these types of registers may include Accumulator register, Index register and Base register among others.
Special Purpose Registers are dedicated to specific tasks such as controlling operations within the microprocessor or keeping track of certain conditions in order to ensure proper execution of programs (Kuckuk et al., 2010). Examples include Program Counter Register which stores address that points to next instruction in program sequence; Instruction Register which is used by Control Unit in fetching instruction from memory; Stack Pointer Register which points to topmost element on stack; Condition Code Register which stores status information about result obtained after completion of last arithmetic/logical operation etc..
All these special purpose registers play an important role in providing efficient processing capabilities by enabling efficient flow control techniques like looping statements and conditional statements.
