$[100$ pts$]$ In this exercise, we look at how software techniques can extract instruction$-$

level parallelism $($ILP$)$ in a common vector loop. The following loop is the so$-$called

DAXPY loop $($double$-$precision aX plus Y$)$ and is the central operation in Gaussian

elimination. The following code implements the DAXPY operation, $Y=ax+Y.$

Initially, $f2$ holds constant $a,x1$ is set to the base address of array $x,$ and $x2$ is set to the

base address of array Y:

$($i$1)$ foo: fld f$0,0(x1),$; load X$($i$)$ to Reg$(f0)$

$($i$2)$ fmul.d $f4,f0,f2,$;Reg$(f4)=a^{**}x(i)$

$($i$3)$ fld f$6,0($x$2)$ ; load Y$($i$)$ to Reg$(f6)$

$($i$4)$ fadd.d f$6,$ f$4,$ f$6$ ; Reg$(f6)=a^{**}x(i)+Y(i)$

$($i$5)$ fsd f$6,0($x$2)$ ; store Reg$($f$6)$ to Y$($i$)$

$($i$6)$ addi $x1,x1,8,$; increase $x$ index

$($i$7)$ addi $x2,x2,8,$; increase $Y$ index

$($i$8)$ sltu $x4,x1,x3,$; test: continue loop? $($if $x4=1x4x1,$ set $x4=1$