Assembler Answers

Suppose we want to add the JAL command to the set of basic MIPS commands introduced at the beginning of Chapter 4. for this purpose,

a) Draw the minimum required changes (data signal, control signal and / or component) on the circuit in Figure 4.24 page 271 of the book computer organization and design by david patterson and draw a new circuit.

b) List the control signals required and their values to execute this new command.

Consider the following emission delays for the circuit in Figure 4.24 , page 271 of the book computer organization and design by david patterson.

a) Calculate the maximum time required to execute the LW, SLT, J, BEQ, ADDI and AND commands.

b) What is the critical path of this processor?

c) What is the maximum frequency of this processor?

nstr. memory read/write: 1.2ns

Data memory read/write: 1.4ns

Register file read/write: 0.5ns

Any ALU operation: 0.5ns

Any 2 to 1 mux: 0.1ns

Any adder (except ALU adder): 0.4ns

Consider Figure 24.4 Page 271of the book computer organization and design by david patterson and complete the table of control signals with values (0, 1 or X - don't care ) for each of the following instructions.

LW SLT J BEQ ADDI AND

RegDst

Jump

Branch

Memread

MemtoReg

MemWrite

ALUSrc

RegWrite

ALU Control Input

Consider Figure 4.24 on page 271 of the textbook computer organization and design by david patterson. Assume that the instruction word is fetched with the following value from the instruction memory. also

Suppose that at the beginning of the cycle in which the command is to be called, all the words in the instruction memory are equal to 0 and r0=0, r1= -1, r2 = 2, r3 = -3, r4 = -4, r5 = 10, r6 = 6, r8 = 8, r12 = 2, r31=-16.

Instruction word: 101011 00011 00010 0000000000010100

a) Get the outputs of sign-extension, jump, shift left 2 units for the instruction word above.

b) What are the inputs of the ALU control unit for the instruction word above.

c) What is the new PC value after this instruction is executed? How will this new value be placed on the PC?

d) While executing this instruction, get the output value of each multiplexer and the values of the registers.

e) Obtain the input values of the ALU and the other two adders (as shown).

f) What are the inputs of the register unit (register file )?

Suppose a program is written with only the add, addi, not, beq, lw and sw commands, and the percentage of use of these commands in that program is 20%, 20%,0%,25%,25%,10% respectively.

a) What percentage of the program's time is spent on data memory? Why?

b) What percentage of the program execution time is the sign-extension circuit used? Why?