Podcast
Questions and Answers
What occurs first in the Store Fetch/Execute Cycle?
What occurs first in the Store Fetch/Execute Cycle?
- PC is transferred to MAR (correct)
- MDR is transferred to IR
- Program Counter is incremented
- Data is copied from accumulator to MDR
What is the purpose of incrementing the Program Counter in the execution cycle?
What is the purpose of incrementing the Program Counter in the execution cycle?
- To load the next instruction into MDR
- To change the instruction type being executed
- To prepare for the next instruction fetch (correct)
- To reset the accumulator value
In the ADD Fetch/Execute Cycle, what operation is performed after transferring the instruction to the IR?
In the ADD Fetch/Execute Cycle, what operation is performed after transferring the instruction to the IR?
- Loading the accumulator with the instruction result
- Copying data from MAR to MDR
- Transferring the address from IR to MAR (correct)
- Adding the contents of MAR to IR
What key difference is noted in Step #4 of the Store Fetch/Execute Cycle compared to the ADD Fetch/Execute Cycle?
What key difference is noted in Step #4 of the Store Fetch/Execute Cycle compared to the ADD Fetch/Execute Cycle?
Which statement accurately describes the role of the Memory Data Register (MDR) during the execution cycles?
Which statement accurately describes the role of the Memory Data Register (MDR) during the execution cycles?
What is one of the main advantages of parallel buses over serial buses?
What is one of the main advantages of parallel buses over serial buses?
Which characteristic best describes serial buses?
Which characteristic best describes serial buses?
Which of the following is a typical application for parallel buses?
Which of the following is a typical application for parallel buses?
What is a primary characteristic of point-to-point bus systems?
What is a primary characteristic of point-to-point bus systems?
What is the significance of data movement instructions in computing?
What is the significance of data movement instructions in computing?
What step occurs after the Program Counter (PC) is incremented in the LMC Fetch/Execute cycle?
What step occurs after the Program Counter (PC) is incremented in the LMC Fetch/Execute cycle?
Which signal is NOT part of the data transfer process in the bus system?
Which signal is NOT part of the data transfer process in the bus system?
What occurs when a branch instruction condition is false in the LMC?
What occurs when a branch instruction condition is false in the LMC?
In the context of the bus, which best describes its purpose?
In the context of the bus, which best describes its purpose?
Which of the following actions is performed by the Instruction Register (IR) during the Fetch/Execute cycle?
Which of the following actions is performed by the Instruction Register (IR) during the Fetch/Execute cycle?
What characterizes a simplex bus?
What characterizes a simplex bus?
Which of the following is NOT a characteristic of buses?
Which of the following is NOT a characteristic of buses?
What is a defining feature of a multipoint bus?
What is a defining feature of a multipoint bus?
Which bus transmission method allows communication in one direction at a time?
Which bus transmission method allows communication in one direction at a time?
What is meant by throughput in the context of bus characteristics?
What is meant by throughput in the context of bus characteristics?
What is the primary characteristic of DRAM?
What is the primary characteristic of DRAM?
Which type of memory is known for being a nonvolatile storage option?
Which type of memory is known for being a nonvolatile storage option?
How many locations can be addressed with 8 bits in an instruction's address portion?
How many locations can be addressed with 8 bits in an instruction's address portion?
Which of the following is true about the fetch-execute cycle?
Which of the following is true about the fetch-execute cycle?
What is a primary advantage of using Flash Memory?
What is a primary advantage of using Flash Memory?
Which of the following describes a characteristic of EEPROM?
Which of the following describes a characteristic of EEPROM?
During the fetch phase of the fetch-execute cycle, what is transferred to the MAR?
During the fetch phase of the fetch-execute cycle, what is transferred to the MAR?
What does SRAM primarily provide in comparison to DRAM?
What does SRAM primarily provide in comparison to DRAM?
Which operation is not typically associated with Boolean logic?
Which operation is not typically associated with Boolean logic?
What does LIFO stand for in relation to stack instructions?
What does LIFO stand for in relation to stack instructions?
Which of the following best describes SIMD?
Which of the following best describes SIMD?
In the context of program control, which action does a subroutine call perform?
In the context of program control, which action does a subroutine call perform?
Which instruction type is primarily concerned with manipulating individual data values?
Which instruction type is primarily concerned with manipulating individual data values?
What does an instruction set of a processor define?
What does an instruction set of a processor define?
Which of the following is true about shift and rotate instructions?
Which of the following is true about shift and rotate instructions?
When performing decrementing on an integer, what is the expected outcome?
When performing decrementing on an integer, what is the expected outcome?
What is a characteristic of an explicit address in an instruction format?
What is a characteristic of an explicit address in an instruction format?
Which of the following is NOT a primary component of an instruction?
Which of the following is NOT a primary component of an instruction?
Which of the following describes a characteristic of bus throughput?
Which of the following describes a characteristic of bus throughput?
What type of bus allows communication in both directions, but only one at a time?
What type of bus allows communication in both directions, but only one at a time?
Which type of interconnection method connects a single source to a single destination?
Which type of interconnection method connects a single source to a single destination?
In terms of bus characteristics, which of the following reflects addressing capacity?
In terms of bus characteristics, which of the following reflects addressing capacity?
Which factor is NOT generally considered a characteristic of a bus?
Which factor is NOT generally considered a characteristic of a bus?
Which operation involves the accumulator during the ADD Fetch/Execute Cycle?
Which operation involves the accumulator during the ADD Fetch/Execute Cycle?
What is the correct sequence of steps when an instruction is being fetched?
What is the correct sequence of steps when an instruction is being fetched?
During which step of the Store Fetch/Execute Cycle does data move from the accumulator to the MDR?
During which step of the Store Fetch/Execute Cycle does data move from the accumulator to the MDR?
What is the main purpose of the Program Counter in the fetch/execute cycle?
What is the main purpose of the Program Counter in the fetch/execute cycle?
In the context of the Store Fetch/Execute Cycle, what specifically differentiates the operation in Step 4 for LOAD and STORE instructions?
In the context of the Store Fetch/Execute Cycle, what specifically differentiates the operation in Step 4 for LOAD and STORE instructions?
What is the maximum number of locations that can be addressed with 32 bits in an instruction's address portion?
What is the maximum number of locations that can be addressed with 32 bits in an instruction's address portion?
Which type of RAM must be refreshed thousands of times each second?
Which type of RAM must be refreshed thousands of times each second?
Which of the following statements about SRAM is correct?
Which of the following statements about SRAM is correct?
Which type of memory is faster but has a slower rewrite time compared to RAM?
Which type of memory is faster but has a slower rewrite time compared to RAM?
During the fetch phase of the fetch-execute cycle, what is the final action taken after loading the instruction from memory?
During the fetch phase of the fetch-execute cycle, what is the final action taken after loading the instruction from memory?
What does EEPROM stand for?
What does EEPROM stand for?
In the fetch-execute cycle, what is the role of the Memory Address Register (MAR)?
In the fetch-execute cycle, what is the role of the Memory Address Register (MAR)?
Which of the following statements accurately describes the limitations of parallel buses?
Which of the following statements accurately describes the limitations of parallel buses?
What is a key advantage of serial buses compared to parallel buses?
What is a key advantage of serial buses compared to parallel buses?
In the context of data movement instructions, which statement is true?
In the context of data movement instructions, which statement is true?
What defines a multipoint bus system?
What defines a multipoint bus system?
What is a distinctive feature of instructions regarding word size?
What is a distinctive feature of instructions regarding word size?
Which component is responsible for performing calculations and comparisons in a CPU?
Which component is responsible for performing calculations and comparisons in a CPU?
What role does the Control Unit play in the CPU's operation?
What role does the Control Unit play in the CPU's operation?
Which register holds the instruction fetched from memory during the execution cycle?
Which register holds the instruction fetched from memory during the execution cycle?
What is a primary function of the Memory Data Register (MDR)?
What is a primary function of the Memory Data Register (MDR)?
How does the Memory Address Register (MAR) contribute to memory operations?
How does the Memory Address Register (MAR) contribute to memory operations?
Which type of registers holds intermediate results and is user-visible?
Which type of registers holds intermediate results and is user-visible?
What aspect of registers allows them to manipulate data quickly during execution?
What aspect of registers allows them to manipulate data quickly during execution?
Which statement best describes the Function of Status Registers?
Which statement best describes the Function of Status Registers?
How does the fetch-execute cycle begin?
How does the fetch-execute cycle begin?
What determines the size of the registers within the CPU?
What determines the size of the registers within the CPU?
What type of instruction word size has largely been eliminated due to pipelining?
What type of instruction word size has largely been eliminated due to pipelining?
Which of the following is an addressing mode used in modern architectures?
Which of the following is an addressing mode used in modern architectures?
What does the first phase of the instruction cycle achieve?
What does the first phase of the instruction cycle achieve?
Which of the following best describes the role of registers in the fetch-execute cycle?
Which of the following best describes the role of registers in the fetch-execute cycle?
What is a characteristic of the Little Man Computer model?
What is a characteristic of the Little Man Computer model?
Which type of memory is characterized as volatile?
Which type of memory is characterized as volatile?
What is the function of the last two digits in the instruction format of the Little Man Computer?
What is the function of the last two digits in the instruction format of the Little Man Computer?
Which of the following addressing modes is associated with directly accessing data in a register?
Which of the following addressing modes is associated with directly accessing data in a register?
Flashcards
MAR bits
MAR bits
The number of bits in the Memory Address Register (MAR) depends on the system's memory capacity. 2 to the power of K, where K = width of the address register in bits.
Instruction Address Size
Instruction Address Size
The amount of bits in the address part of an instruction defines how many memory locations the computer can access.
DRAM
DRAM
Dynamic RAM is a common, inexpensive type of RAM that needs to be continuously refreshed to maintain data, making it volatile.
SRAM
SRAM
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ROM
ROM
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Fetch Cycle
Fetch Cycle
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Execute Cycle
Execute Cycle
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Fetch-Execute Cycle
Fetch-Execute Cycle
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PC Increment
PC Increment
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Program Counter (PC)
Program Counter (PC)
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Memory Address Register (MAR)
Memory Address Register (MAR)
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Memory Data Register (MDR)
Memory Data Register (MDR)
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What is the role of the Instruction Register (IR)?
What is the role of the Instruction Register (IR)?
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What is a bus?
What is a bus?
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Serial Buses
Serial Buses
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Parallel Buses
Parallel Buses
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Point-to-point
Point-to-point
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Broadcast Bus
Broadcast Bus
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Data Movement Instructions
Data Movement Instructions
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Bus Categorizations
Bus Categorizations
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Simplex Transmission
Simplex Transmission
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Multipoint Bus
Multipoint Bus
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What are arithmetic instructions used for?
What are arithmetic instructions used for?
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What are boolean logic instructions used for?
What are boolean logic instructions used for?
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What does a single operand manipulation instruction do?
What does a single operand manipulation instruction do?
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Bit Manipulation
Bit Manipulation
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Program Control Instructions
Program Control Instructions
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What is a stack?
What is a stack?
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What are multiple data instructions?
What are multiple data instructions?
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What is SIMD?
What is SIMD?
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What is an instruction format?
What is an instruction format?
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What is an instruction set?
What is an instruction set?
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CPU Components
CPU Components
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What are Registers?
What are Registers?
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Types of Memory
Types of Memory
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What is the role of the ALU?
What is the role of the ALU?
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What is the role of the Control Unit?
What is the role of the Control Unit?
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What is the Fetch-Execute Cycle?
What is the Fetch-Execute Cycle?
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What does the PC do during the Fetch-Execute Cycle?
What does the PC do during the Fetch-Execute Cycle?
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What is the MAR's role?
What is the MAR's role?
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What does the MDR do?
What does the MDR do?
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How does the MDR differ in LOAD and STORE Instructions?
How does the MDR differ in LOAD and STORE Instructions?
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Bus Characteristics
Bus Characteristics
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Point-to-point vs. Multipoint Bus
Point-to-point vs. Multipoint Bus
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What's the size of a word?
What's the size of a word?
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Instruction Word Size
Instruction Word Size
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Fixed Instruction Size
Fixed Instruction Size
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Variable Instruction Size
Variable Instruction Size
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Addressing Modes
Addressing Modes
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Direct Addressing
Direct Addressing
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Register Deferred Addressing
Register Deferred Addressing
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Instruction Format
Instruction Format
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Study Notes
System Software and Computing Concepts - CPU and Memory
- The course covers CPU components, registers, memory units, fetch-execute cycles, buses, and instruction/word formats.
- Learning outcomes include describing a computer system's structure, components, and functions.
- Key terms include instruction cycle, linear memory addressing, Little Man Computer (LMC), mnemonics, op code, stored program concept, and von Neumann architecture.
- Major CPU components include the ALU (arithmetic logic unit) for calculations and comparisons, and the CU (control unit) for the fetch/execute cycle, commanding the ALU and managing data movement between the CPU registers and other hardware.
- Subcomponents: the memory management unit and I/O interface, sometimes combined as a bus interface unit.
- A system block diagram shows the CPU, ALU, control unit, memory and I/O interface, program counter.
- The Little Man Computer (LMC) provides a simplified model of a computer.
- DRAM is the most common type of RAM, inexpensive, less power-consuming, and requires data refreshing.
- SRAM is faster and more expensive than DRAM.
- ROM stores software that typically does not change during operation.
Concept of Registers
- Registers are small, permanent storage locations within the CPU, specialized for specific tasks.
- The control unit directly manipulates registers.
- Registers hold data, addresses, or instructions in bit or byte sizes (not megabytes like memory).
Use of Registers
- Registers act as scratchpads for currently running programs; they hold frequently accessed data.
- Registers store CPU status and program execution information.
- They hold next instruction addresses and signals from external devices.
- General-purpose registers hold intermediate results or data (ex: loop counters) like LMC's calculator, and are commonly used in current CPUs.
Special-Purpose Registers
- The program counter (PC), also known as the instruction pointer, indicates the next instruction.
- The instruction register (IR) stores the fetched instruction from memory.
- The memory address register (MAR) holds the memory address required for data retrieval or storage.
- The memory data register (MDR) is a two-way register transferring data to and from memory.
- Status registers contain CPU status, using flags (bit-sized Boolean variables) to track conditions like arithmetic errors (carry/overflow), power failure.
Register Operations
- Registers store data from other registers and memory locations.
- Common operations include addition, subtraction, data shifting/rotation, and testing for conditions like zero or positive.
Operation of Memory
- Each memory location has a unique address.
- Memory address registers (MAR) hold addresses fetched from instructions.
- The CPU determines if the address is for a retrieval or storage operation.
- Data transfers occur between the memory data register (MDR) and memory.Â
- The MDR is a two-way register.
Relationship between MAR, MDR, and Memory
- The memory address register (MAR) decodes memory addresses.
- The memory data register (MDR) stores the data that is being operated on or moved to or from memory.
MAR-MDR Example
- Diagram shows the relationship between the memory address and data registers, and memory.
Visual Analogy of Memory
- A visual representation of how the address decoder and memory data register work with each other to select a specific memory location.
Individual Memory Cell
- Describes the mechanisms for writing and reading data to/from a memory location, using address lines, R/W line ("read/write"), and MDR line.
Memory Capacity
- Memory capacity depends on the number of bits in the memory address register (MAR) and the size of the address portion of the instruction.
- 2n (where n = width of register in bits) determines the number of accessible memory locations.
- Different register widths support different numbers of storage locations.
RAM: Random Access Memory
- DRAM (Dynamic RAM) is the most common type, inexpensive, less power-consuming, and requires refreshing to maintain data.
- SRAM (Static RAM) is faster and more expensive than DRAM. It is used in cache memory for high-speed access. Both are volatile.
Nonvolatile Memory
- ROM (Read-Only Memory) stores software that typically does not change during operation and is nonvolatile.
- EEPROM (Electrically Erasable Programmable ROM) is a form of ROM or programmable read-only memory that can be erased.
- Flash memory is faster than hard disks, but has slower rewrite times than RAM.
Fetch-Execute Cycle
- A two-step (Fetch & Execute) process.
- Fetch: Instruction decoding and loading from memory to a register.
- Execute: Performing the operation that the instruction requires.
LMC vs. CPU Fetch and Execute Cycle
- Shows comparison between the operation of the LMC's fetch-execute cycle and a CPU's equivalent cycle.
Load Fetch/Execute Cycle
- Detailed steps for loading data into the accumulator of the CPU.
Store Fetch/Execute Cycle
- Shows how the CPU stores data from the accumulator to a memory location.
ADD Fetch/Execute Cycle
- Detailed steps for the process of adding data to the accumulator of the CPU.
LMC Fetch/Execute (SUBTRACT)
- Steps for the calculation of subtraction.
Bus
- The physical connection enabling data transfer between locations in a computer system.
- Composed of multiple lines (conductors) that carry various signals.
- Four common signal types are data, addressing, control, and power (sometimes).
Bus Characteristics
- Number of conductors and data width.
- Addressing capacity.
- Signal throughput rate.
- Distance limitations.
Bus Categorizations
- Parallel vs serial buses: comparison in data transfer speeds and complexity.
- Direction of transmission (simple, half-duplex, full-duplex).
- Interconnection methods (point-to-point, multipoint).
Parallel vs Serial Buses
- Parallel buses transfer multiple bits simultaneously
- Serial buses transfer one bit at a time
Point-to-point vs Multipoint
- Point-to-Point Buses connect two devices directly.
- Multipoint buses connect multiple devices to a common device.
Classification of Instructions
- Data Movement (Load/Store): most flexible, involves memory and registers.
- Arithmetic: performing addition/subtraction/multiplication/division, integers and floating-point operations.
- Boolean Logic: includes AND, XOR, NOT operations.
- Single Operand Operations: negating, decrementing, incrementing, setting to zero.
More Instruction Classifications
- Bit manipulation, flags, shift, rotate, program control, stack manipulation, multiple data instructions, and I/O and machine control.
Register Shifts and Rotates
- Types of logical and arithmetic shift/rotate operations.
Program Control Instructions
- Examples of program control instructions including jumps, branches, subroutine calls, and returns.
Stack Instructions
- LIFO (Last-In, First-Out) method for organized data.
- Stack instructions involve PUSH and POP operations.
Block of Memory as a Stack
- PUSH: increments the stack pointer and stores data on the stack
- POP: loads data from the stack by decrementing the stack pointer.
Multiple Data Instructions
- SIMD (Single Instruction, Multiple Data) performs the single operation concurrently on multiple data.
Instruction Format Examples
Instruction Format
Instructions
- Instructions are directions given to a computer.
- Instruction sets define actions the processor performs.
- Key components are number and complexity of instructions, data types, format, use of registers, and addressing.
Instruction Word Size
- Fixed vs variable instruction sizes.
- Most current architectures use 32 or 64-bit words.
- Addressing modes (mode used by LMC, Register Deferred, immediate, indirect, indexed).
Quick Review Questions
- Questions on the instruction cycle, von Neumann architecture, volatile/nonvolatile memory, registers, fetch-execute cycle, Little Man Computer, and memory.
Summary
- The Little Man Computer provides an analogy to a computer's internal operations (input/output, arithmetic logic unit, memory).
Q&A
- Section for questions and answers.
Next
- The next topic for the course is CPU and Memory.
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Description
This quiz explores the essential concepts related to the Fetch/Execute Cycle in computer architecture. You will test your understanding of the roles of the Program Counter, Memory Data Register, and various types of bus systems. Gain insights on data movement instructions and their significance in computing.
