Project 3 SRC Arithmetic Logic Unit Free World

Project #3 SRC Arithmetic Logic Unit Free World Alexis Torres Mannix Flores Angel Arroyo Omar A. Cruz Salgado

Arithmetic Logic Unit • Objectives: – Designing an arithmetic logic unit (ALU) for a reduced instruction set computer (RISC) processor was the main objective in this project. – This ALU had to be able to implement the basic arithmetic and logic operations of the processor as the different operations of value transfer movements. – The (Simple RISC Computer’s (SRC’s) ALU will provide the necessary hardware for the implementation of the arithmetic and logic instructions of the processor.

Arithmetic Logic Unit • Intro: – An arithmetic-logic unit (ALU) is the heart of the machine. It is the part of a computer processor (CPU) that carries out arithmetic and logic operations on the operands in computer instruction. – In some processors, the ALU is divided into two units, an arithmetic unit (AU) and a logic unit (LU).

Arithmetic Logic Unit – Internally the ALU has 2 registers used to store temporary values inputs and the results of a given operation. – All the components communicate internally using a bus. This is the same bus used to input/output values to the ALU. – We use 2’s compliment to achieve the arithmetic expression.

Arithmetic Logic Unit • Basic components: – Full Adder

Arithmetic Logic Unit • Basic components: – Shifters: Left shifter: Right shifter:

Arithmetic Logic Unit • More complex components: Shift and logic:

Arithmetic Logic Unit • Complete ALU:

Arithmetic Logic Unit • Timing Diagram for negation:

Arithmetic Logic Unit • Timing Diagram for the SHL:

Arithmetic Logic Unit • Conclusion: – The ALU is the “heart” of the CPU. It is where vital arithmetic and logic operations take place. – It is a combinational circuit that continuously computes its output as a function of the inputs. – The best approach to create the ALU, is by breaking it into simpler units that are easy to visualize and interconnect.

Arithmetic Logic Unit • References: – V. P. Heuring, H. F. Jordan, Computer System Design and Architecture. 2 nd Ed. , New Jersey: Pearson Prentice Hall, 2004. – P. J. Ashenden, The Designer's Guide to VHDL. 2 nd Ed. , San Francisco: Morgan Kaufmann, 2002. – N. G. Santiago, M. A. Jiménez, Writing Formal Reports. 3 rd Ed. , Dept. Electri. and Comp. Eng. , Univ. of Puerto Rico, 2002. – Encarta, “Arithmetic Logic Unit, ” URL – http: //encarta. msn. com/dictionary_1861584975/ALU. html

Arithmetic Logic Unit • Acknowledgements: – Thanks to Nayda Santiago, who took time to teach us. She showed us the way to find our own paths and tools. – Thanks to Omar’s daughter Sofia, she made it possible for us to finish early today. – Thanks to Omar and family for the long hours we spend in his house working/eating/learning/babysitting.