Write a Y86 program sum.ys that iteratively sums the elements of a linked list. should consist of some code that sets up the stack structure, invokes a function, and then halts. example of code in C form below.

int sum_list(list_ptr ls)

{ int val = 0;

while (ls)

{ val += ls->val;

ls = ls->next;

}

return val;

}