Random Array

Write an assembly function fill$\_$array that takes two arguments: a $64-$bit signed integer array pointer and the number of elements. It should fill the array with random values $($generated using your randint$).$

We don't want our array values to be too big, so we'll keep the array elements in the range $-128127($but still as $64-$bit integers$).$ Hint:

call randint

and $$0$xff$,\%$rax

sub $$128,\%$rax

Dot Product

Write an assembly function dot that takes two $(64-$bit signed integer$)$ array pointers and a length $($assumed to be the same for both arrays$).$ It should return the dot product of the two arrays, i$.$e$.$

arr$1[0]*$arr$2[0]+$ arr$1[1]*$arr$2[1]++$ arr$1[$n$]*$arr$2[$n$]$

Array of Structs

Instead of working with pairs of arrays, maybe we should work with arrays of pairs. The provided lab$7.$h defines this struct:

typedef struct $\{$

int$64\_$t a;

int$64\_$t b;

$\}$ pair$64\_$t;

In C$,$ we know that array elements are guaranteed to be adjacent in memory, but struct members are also guaranteed to be arranged in memory in the order they're declared. We generally expect them to be adjacent, so this struct should take $16$ bytes: the first $8$ bytes are a and the next $8$ are b$.($It$\text{'}$s actually a little more complicated than that because of padding and alignment, but we can ignore those for now.$)$

Repeat the dot product calculation, but taking a single array of pair$64\_$t $($and a length$)$ as arguments.

Speed

The included timing.c will do some timing of your implementations, as well as C implementations in lab$7$c$.$c$.$ Have a look. $$

Questions

Answer these questions in a text file answers.txt$.$

What commands did you use to compile$/$assemble and run your code for this lab?

How did the running times compare for the various dot product implementations?