Designing, Implementing and Verifying Arithmetic and Logic Unit - Report Example

Abstract This report aimed at designing, implementing and verifying arithmetic and logic unit in the 6502. The arithmetic and logic unit was designed in very-high-speed integrated circuit hardware description language (VHDL). The designed ALU is an eight bit unit which will be able to perform various logical operations such as additions, subtractions, OR, ADD, SOR division and multiplication. It has three registers which two of them will hold the input values and one store output. The VHDL code for the ALU has been included as well as snapshots for verification plan. Table of Contents Abstract 1 1.0Introduction 3 1.1 Motivation 4 Working principle 4 Mapping State and signal control 7 VHDL models 7 VHDL Code 9 esults 18 Conclusion 18 References 19 1.0Introduction Microprocessor essentially is a work space and scratch path for the CPU. The CPU both fetches information from and temporarily store information in the memory. More memory typically means that a computer can run larger software applications in the memory. More memory typically means that a computer can run larger software applications and do certain tasks faster. In general, input devices and out devices communicate information between the computer and it users or between itself and other computers. Digital computers use the binary number system rather than the decimal number system, to represent numbers. The binary number system has only two digits, 0 and 1. A binary digit is referred to as bit. The binary number system is used because is used because the fundamental building bloc; of a computer is a switch, much li;e the familiar on/off switch for an electric light. The state of the switch indicators whether the value of the associated digit is 0 or 1. In early computers, these switches were built from mechanical relays. The resulting machines were huge. They occupied an entire room, and they required special power and cooling. In today’s machines, the switches are made from utrasmall transistors. Consequently, an entire computer can fit on a single silicon chip. Because the entire computer fits on a chip, these chips are referred to as microprocessors. The aim of the project was to design, implement, in VHDL and verify arithmetic and logic unit for 6502 microprocessor. The processor that was designed was assumed to have a single clock; unlike the 6502 processor. It should have three registers which will be use in holding input-output values as well as have the ability to perform all logical operations derived from OR, ADD, as well as XOR. It also had the ability to carry out arithmetic operations such as addition, subtraction, multiplication and division. It should be in a position to do both shift light and shift left operations. Subtraction in the designed ALU is done through the use of compliment addition, while division will be done as the case of 6502 microprocessor. The 6502 microprocessor designed accepts 16 bits numbers as well as a code that will implement any of logic operations. The system has the ability to accept and implement all arithmetic and logic unit inputs and generate necessary results for the user. It has two binary inputs which produces results logically. It has also included operations like, exponential, greater than, equals to, less than, raised to, percentage and many others that are included. All these have been designed and implemented in VHDL code the results obtained from running the code is verified through simulation. 1.1 Motivation There are many reasons that have motivated the design of this microprocessor. On e of them is to create a new microprocessor that will be able to calculate and perform various logical operations with ease. It will be used to calculate the address for indexed and relative addressed modes. The 6502 microprocessor uses eight bit address to cover its functions, however, this designed microprocessor will carry out additions in two stages for the sixteen bit addresses, and that is, low bit plus index register, high-byte, low byte plus index register, high-byte plus carry from previous index register. Working principle The arithmetic and logic unit simply performs operations Generating Timing Diagrams Figure 1:block diagram Mapping State and signal control VHDL models Generally, a processor can be described as a mathematical model and is a basic component of any system that is intended to exhibit autonomous behavior in a complex environment. Connection lines those are responsible for transmitting information between the processors. Similar to the various locations that the processors can be implemented at, the lines of hardware can also be implemented in different locations. 1. Although a single processor is capable of receiving multiple inputs from mother processors, it can only have a single output leading to other processors. 2. The processor output can take on any type of mathematical form depending on its input. 3. Modifying the memory of the processors so it can be adapted to the environment. Given the fact that neural networks are non-linear and flexible, they can be adapted to and used within various activities such as prediction and forecasting, system identification, classification, optimization and decision support. The following block diagram VHDL Code esults Screenshot Conclusion The design, implementation and validation of 6502 microprocessor was successful and helped to learn fundamental of ALU design. Significantly, it is vital to consider having the knowledge concerning the advanced methods regarding the 6502 microprocessor all the way to the diagnosis. In addition, it was important to consider the vital areas like the testing as well as the technicality of the processes is guaranteed. Following this process, error occurs with similar processes while considering the relationship that does exist between signals like the parameter estimation, observers, component analysis and parity equations. Ultimately, the collected information is then recorded into a known memory for future reference and can be used for other calculations. References Brown,S. & Zvonko,V., 2005. “Fundamentals of digital logic with VHDL Design” 2nd Edition, New York: McGraw Hill International. Dewey, A. 1997. “Analysis and design of digital system with VHDL”, PWS publishing company. Grantner, J. L., Tamayo,P.A., Gottipati,R. & Florida, D., 2005. Development of a Test Bench for VHDL Projects. American Society for Engineering Education Annual Conference & Exposition McCabe, P., 2010. VHDL-based system simulation and performance management. Honeywell Inc. Space systems. Zwolinski, M., 2000. “Digital System Design with VHDL”, New York: Prentice Hall, 2000. Read More