Deadline: EOL (End of Lab) Friday, October 18th
Like in previous weeks, we will be using the Venus RISC-V simulator (which can be found online here).
megalistmanips.s
In Lab 4, you completed a RISC-V procedure that applied a function to every element of a linked list. In this lab, you will be working with a similar (but slightly more complex) version of that procedure.
Now, instead of having a linked list of int
’s, our data structure is a linked
list of int
arrays. Remember that when dealing with arrays in struct
’s, we
need to explicitly store the size of the array. In C code, here’s what the data
structure looks like:
struct node {
int *arr;
int size;
struct node *next;
};
Also, here’s what the new map
function does: it traverses the linked list and
for each element in each array of each node
, it applies the passed-in function
to it, and stores it back into the array.
void map(struct node *head, int (*f)(int)) {
if (!head) { return; }
for (int i = 0; i < head->size; i++) {
head->arr[i] = f(head->arr[i]);
}
map(head->next, f);
}
Record your answers to the following questions in a text file. Some of the questions will require you to run the RISC-V code using Venus’ simulator tab.
megalistmanips.s
. Read
all of the commented lines under the map
function in megalistmanips.s
(before it returns with jr ra), and make sure that the lines do what the
comments say. Some hints:
jal
?add t0, s0, x0
and lw t0, 0(s0)
?struct node
.map
, mapLoop
, and done
functions but
it’s worth understanding the full program.s
registers outside of s0
and s1
.f
in map
), we want you to use temporary registers
instead and follow their caller/callee conventions. The provided map
implementation uses the s0
and s1
registers, so we’ll require that you
don’t use s2
-s11
.megalistmanips.s
file. Running on Venus,
you should see the following output:Lists before:
5 2 7 8 1
1 6 3 8 4
5 2 7 4 3
1 2 3 4 7
5 6 7 8 9
Lists after:
30 6 56 72 2
2 42 12 72 20
30 6 56 20 12
2 6 12 20 56
30 42 56 72 90
At this point, make sure that you are comfortable with the following. Note that these will not be part of the lab checkoff, but are meant to benchmark how comfortable you are with the material in the exercise.
Consider the discrete-valued function f
defined on integers in the set
{-3, -2, -1, 0, 1, 2, 3}
. Here’s the function definition:
f(-3) = 6
f(-2) = 61
f(-1) = 17
f(0) = -38
f(1) = 19
f(2) = 42
f(3) = 5
discrete_fn.s
in RISC-V, with the condition that
your code may NOT use any branch and/or jump instructions!discrete_fn.s
.Please submit to the Lab Autograder assignment (same as last week!).