GATE CSE
Computer Organization
Pipelining
Previous Years Questions

## Marks 1

A processor X1 operating at 2 GHz has a standard 5-stage RISC instruction pipeline having a base CPI (cycles per instruction) of one without any pipel...
Register renaming is done in pipelined processors
For a pipelined $$CPU$$ with a single $$ALU$$, consider the following situations $$1.\,\,\,\,\,$$ The $$j+1$$ instruction uses the result of the $$j$$...
Comparing the time $$T1$$ taken for a single instruction on a pipelined $$CPU$$ with time $$T2$$ taken on a non-pipelined but identical $$CPU,$$ we ca...

## Marks 2

A five-stage pipeline has stage delays of 150, 120, 150, 160 and 140 nanoseconds. The registers that are used between the pipeline stages have a delay...
Consider the following instruction sequence where register R1, R2 and R3 are general purpose and MEMORY[X] denotes the content at the memory location ...
Consider a non-pipelined processor operating at 2.5 GHz. It takes 5 clock cycles to complete an instruction. You are going to make a 5-stage pipeline ...
The instruction pipeline of a $$RISC$$ processor has the following stages: Instruction Fetch $$(IF),$$ Instruction Decode $$(ID),$$ Operand Fetch $$(O... Suppose the functions$$F$$and$$G$$can be computed in$$5$$and$$3$$nanoseconds by functional units$${U_F}$$and$${U_G},$$respectively. Given ... Consider a$$3GHz$$(gigahertz) processor with a three-stage pipeline and stage latencies$${\tau _1},{\tau _2},$$and$${\tau _3}$$such that$$...
The stage delays in a $$4$$-stage pipeline are $$800, 500, 400$$ and $$300$$ picoseconds. The first stage (with delay $$800$$ picoseconds) is replaced...
Consider the following reservation table for a pipeline having three stages $${S_1},{S_2}$$ and $${S_3}.$$ The minimum average latency $$(MAL)$$ is ...
Consider the sequence of machine instructions given below: .tg {border-collapse:collapse;border-spacing:0;border:none;} .tg td{font-family:Arial, s...
Consider a non-pipelined processor with a clock rate of 2.5 gigahertz and average cycles per instruction of four. The same processor is upgraded to a ...
Consider the following processors ($$ns$$ stands for nanoseconds). Assume that the pipeline registers have zero latency. $$P1:$$ Four-stage pipeline w...
An instruction pipeline has five stages, namely, instruction fetch $$(IF),$$ instruction decode and register fetch $$(ID/RF)$$ instruction execution \$...
Consider a $$6$$-stage instruction pipeline, where all stages are perfectly balanced. Assume that there is no cycle-time overhead of pipelining. When ...
Consider an instruction pipeline with five stages without any branch prediction: Fetch Instruction $$(FI),$$ Decode Instruction $$(DI),$$ Fetch Operan...
Consider an instruction pipeline with four stages $$\left( {S1,\,S2,\,S3,} \right.$$ and $$\left. {S4} \right)$$ each with combinational circuit only....
A $$5$$-stage pipelined processor has Instruction Fetch $$(IF),$$ Instruction Decode $$(ID),$$ Operand Fetch $$(OF),$$ Perform Operation $$(PO)$$ and ...
Consider a $$4$$ stage pipeline processor. The number of cycles needed by the four instructions $${\rm I}1,$$ $${\rm I}2,$$ $${\rm I}3,$$ $${\rm I}4,... The following code is to run on a pipelined processor with one branch delay slot$$\eqalign{ & {{\rm I}_1}:\,\,ADD\,\,{R_2}\,\, \leftarrow \,\,{...
In an instruction execution pipeline, the earliest that the data $$TLB$$ (Translation Look aside Buffer) can be accessed is
Which of the following are NOT true in a pipelined processor? $$1.$$ Bypassing can handle all RAW hazards $$2.$$ Register renaming can eliminate all r...
The use of multiple register windows with overlap causes a reduction in the number of memory accesses for $$1.\,\,\,\,$$ Function locals and parameter...
Consider a pipelined processor with the following four stages $$\,\,\,\,\,$$$$IF:$$ Instruction Fetch $$\,\,\,\,\,$$$$ID:$$ Instruction Decode and Ope...
A CPU has five stages pipeline and runs at $$1$$ $$GHz$$ frequency. Instruction fetch happens in the first stage of the pipeline. A conditional branch...
A $$5$$ stage pipelined $$CPU$$ has the following sequence of stages $$IF$$-Instruction fetch from instruction memory, $$RD$$-Instruction decode and r...
A $$4$$-stage pipeline has the stage delays as $$150, 120,160$$ and $$140$$ nano seconds respectively. Registers that are used between the stages have...
The performance of a pipelined processor suffers if

## Marks 5

An instruction pipeline has five stages where each stage takes $$2$$ nanoseconds and all instructions use all five stages. Branch instructions are not...
An instruction pipeline consists of $$4$$ stages: Fetch (F), Decode field (D), Execute (E), and Result-Write (W). The $$5$$ instructions in a certain ...
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