You need to modify the assembly code, which you developed in the previous exercise, with the RISC$-$V V

extension. It is important to note that the specification of the vector engine of our virtual RISC$-$V $($i$.$e$.,$

vlen$=256,$ elen$=16)$ is different from the one used in the previous exercise $($i$.$e$.,$ vlen$=128,$ elen$=16).$

Specifically, you are asked to achieve the same speed up as arraymul$\_$improved$\_$version$1.$c in the

previous exercise. In other words, to get familiar with the design of the vector engine, the performance

improvement of this assignment against the baseline version in $3-2$ array multiplication should be the same as

the performance improvement achieved in $3-3.$ Array multiplication $($a vectorized version with the V extension,

improved$\_$version$1).$ Besides, you should do the same as $3-3$ to collect performance data and derive related

performance statistics.

As shown in the improved$\_$version$2()$ function, you are responsible for writing the assembly for the

for$-$loop code: for $(...)$ y$[$i$]=$ h$[$i$]*$ x$[$i$]+$ c;$.$

NOTE: You should put your assembly code within the arraymul$\_$improved$\_$version$2.$c file, as

indicated in asm volatile$($ #include "arraymul$\_$improved$\_$version$2.$c$"$ : $[$h$]"+$r$"$

$($p$\_$h$),...)$; within the improved$\_$version$2()$ function in exercise$2\_2.$c$.$

Your code should use the RISC$-$V V Extension and run with Spike simulator using the specific

configurations $($i$.$e$.,$ vlen$=256,$ elen$=16).$

NOTE: Please do not modify the rest of the header file.

Variables$/$Constants defined in the header files used in this exercise.

Var.$/$Cons$.$ Name Definition

x$[]$ Input array $1$ in arraymul.h

h$[]$ Input array $2$ in arraymul.h

y$[]$ Output array in arraymul.h

improved$\_$version$2\_$cycle$\_$count

Clock cycle in vectorsum$\_$improved$\_$version$2.$c you need

to calculate

cycle$\_$time

The given clock cycle time of the target RISC$-$V processor

running at $2\mathrm{.}6$ GHz

improved$\_$version$2\_$cpu$\_$time

The CPU time in vectorsum$\_$improved$\_$version$2.$c you

need to calculate

arr$\_$size Size of the arrays used in this exercise

student$\_$id

student$\_$id $=$ your$\_$student$\_$id $\%100$

i$.$g$.$ F$12345678$:

student$\_$id $=12345678\%100=78$

Your obtained scores of this exercise is determined by the correctness of your reported performance

data.

$1.$ Achieved speedup.$(10\%)$

As described above, the printed out speedup number should be $1.$

The improved$\_$version$2$ function in exercise$2\_2.$c is as follows.

$//$The code snippet for improved$\_$version$2()$ in exercise$2\_2.$c

void improved$\_$version$2()\{$

short int $*$p$\_$h $=$ h;

short int $*$p$\_$x $=$ x;

short int $*$p$\_$y $=$ y;

short int id $=$ student$\_$id;$//$ id $=$ your$\_$student$\_$id $\%100$;

$/*$ original C code

for $($int i $=0$; i $<$ arr$\_$size; i$++)\{$

p$\_$y$[$i$]=$ p$\_$h$[$i$]*$ p$\_$x$[$i$]+$ id;

$\}$

$*/$

asm volatile$($

#include "arraymul$\_$improved$\_$version$2.$c$"$

: $[$h$]"+$r$"($p$\_$h$),[$x$]"+$r$"($p$\_$x$),[$y$]"+$r$"($p$\_$y$),[$add$\_$cnt$]"+$r$"($add$\_$cnt$),$

$[$sub$\_$cnt$]"+$r$"($sub$\_$cnt$),[$mul$\_$cnt$]"+$r$"($mul$\_$cnt$),[$div$\_$cnt$]"+$r$"($div$\_$cnt$),$

$[$lw$\_$cnt$]"+$r$"($lw$\_$cnt$),[$sw$\_$cnt$]"+$r$"($sw$\_$cnt$),[$others$\_$cnt$]"+$r$"($others$\_$cnt$)$

: $[$id$]"$r$"($id$),[$arr$\_$size$]"$r$"($arr$\_$size$)$

: $"$t$0","$v$0","$v$1","$v$2"$

$)$;

printf$("$

$=====$ Question $2-2=====$

$")$;

printf$("$output: $")$;

for $($int i $=0$; i $<$ arr$\_$size; i$++)\{$

printf$("\%$d $",$ y$[$i$])$;

$\}$

printf$("$

$")$;

printf$("$add counter used: $\%$d

$",$ add$\_$cnt$)$;

printf$("$sub counter used: $\%$d

$",$ sub$\_$cnt$)$;

printf$("$mul counter used: $\%$d

$",$ mul$\_$cnt$)$;

printf$("$div counter used: $\%$d

$",$ div$\_$cnt$)$;

printf$("$lw counter used: $\%$d

$",$ lw$\_$cnt$)$;

printf$("$sw counter used: $\%$d

$",$ sw$\_$cnt$)$;

printf$("$others counter used: $\%$d

$",$ others$\_$cnt$)$;

macro$\_$improved$\_$version$2\_$cycle$\_$count

printf$("$The total cycle count in this program: $\%\mathrm{.}0$f

$",$

improved$\_$version$2\_$cycle$\_$count$)$;

macro$\_$improved$\_$version$2\_$cpu$\_$time

printf$("$CPU time $=\%$f us

$",$ improved$\_$version$2\_$cpu$\_$time$)$;

float speedup $=0\mathrm{.}0$;

FILE $*$fp;

fp $=$ fopen$("$improved$\_$version$1\_$cpu$\_$time.txt$","$r$")$;

fscanf$($fp$,"\%$f$",$ &speedup$)$;

fclose$($fp$)$;

speedup $=$ speedup $/$ improved$\_$version$2\_$cpu$\_$time;

printf$("$The enhanced V extension version is $\%$f times faster than the baseline

vectorized version

$",$ speedup$)$;

$\}$