8/10/2019 assign5.pdf
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Assignment #5 due: beforeclass begins on November 18 (Tuesday)
Student name: _________________
5. A processor uses a 6-stage instruction pipeline. Assume that
each stage takes a constant amount of time T to
complete. If 200 instructions are executed without encountering
any hazard and every instruction completes
every stage of the pipeline, what is the amount of time from the
moment the first stage for the firstinstruction begins to the
moment the last stage for the last instruction completes?
Answer: ___________T
6. Two statements x=x+7;and x=x-3;are executed concurrently (in
parallel) and their executions may
overlap in time. No mutual exclusion is enforced. Note the two
statements share the variable x, whose
initial value is 20 before the two statements begin execution.
Right after both statements complete
execution, the three possible values of x are _____, _____, and
_____ .
7. We wish to add the following instruction to the instruction
set of EX-1. Note x is a 12-bit field used as a
constant in this instruction.
binary code mnemonic meaning English
1111 x ADC x AC = AC + x add constant
Assume the execute phase of the instruction begins at control
store address 100. Write microinstructions forthe execute phase of
this instruction. Be sure to indicate the control store address for
each microinstruction
that you write. Try to minimize the number of microinstructions
(machine cycles) used in the execute phase.
For each microinstruction, write a comment (beginning with //)
to explain the effect of themicroinstruction.
Hint:remember that when the execute phase begins, the
instruction is in ir.
100:
