APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SECOND SEMESTER M.TECH DEGREE EXAMINATION, MAY 2016
Branch: Computer Science & Information Technology

(All Specializations)
OICS6102: Parallel Computer Architecture
Time: 3Hrs Max. Marks:60
Part A (Each Question Carries 9 Marks)

1.a) Discuss Flynn's Taxonomy based architectures specifying the application of each one (5)

0) We have a program of 1000 instructions in the format cf"lw, add, IWI add, ...."
The add instruction depends (and only depends) on the Iw instruction right before it. The lw instruction

depends (and only depends) on the add instruction right before it If the program is executed on the
pipelined datapath with 5 stages (IF-ID&DR-EXE-MEM-WB).
(1) What would be the actual CPI if operand forwarding is permitted?
(2) Without forwarding, what would be the actual CPI?
Format : LOAD Rdest,#consta
ADD RdestRsrc1 , Rsrc2

2 a) Suppose we are designing an instruction set architecture with 28-bit instructions and 44 different opcodes
Immediate operands can be in the range of 17512. How many registers can this data path have? Assume

we would like to support an R-type and an I-type instruction format with the same operand number and
types used in the MIPS format. FiEl up the following

(1) For | ‏:عملي‎ Opcode: ? Dest_ Register: ? Sourcel Reg: ? Immediate: ?

(2) For R-type:Opcode: ? Dest_ Register: ? Sourcel Reg: ? Source2 Reg: ? (3)
b) Explain some basic compiler techniques for exposing Instruction Level Parallelism (6)

3. a) Suppose you have the following instruction sequence to be executed

lw 51, 0(57)
addi 51, $1, 1
sw $10,
10(57) Iw 52,
0($8) addi $2,
52.1
sw $20, 10(58)

Rearrange the instruction sequence so that it achieves the same functionality but best performance
(shortest execution time). You are only allowed to change the order of the six instructions. Do not

modify or add new instructions. Calcu:ate the execution time of the instruction sequence you
rearranged