Week 10 Laboratory Exercises

It implements a very simple webserver which you can compile and run:

dcc web_server.c serve_web_page.c -o web_server
./web_server

From your web browser try one of these URLs
http://localhost:32517/example.html
http://localhost:32517/bird.html

If you access one of these URLs, they'll tell you that function serve_web_page is unimplemented. Your task in this exercise is to implement this function:

Your task is to add code to this function in serve_web_page.c:

// pathname is the pathname component of a URL
// if a corresponding file exists the client is sent
// a 200 header assuming file contains HTML
// followed by the file contents
// if a the file can't be opened
// a 404 header is sent with no body
void serve_web_page(char *pathname, FILE *client_stream) {

    // REPLACE WITH YOUR CODE
    fprintf(client_stream, HEADER_404);
    fprintf(client_stream, "You requested %s but function serve_web_page is unimplemented\n", pathname);

}

If the request file does not existsserve_web_page should write a 404 header to client_stream (and nothing else).

When you've done this the URL for example.html should show a very simple web page in your browser and and the one for bird.html should show a flying bird.

Use make(1) to build your code:

make    # or 'make serve_web_page'

When you think your program is working, you can use autotest to run some simple automated tests:

1521 autotest serve_web_page

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1521 lab10_serve_web_page serve_web_page.c

Note, even though this is a pair exercise, you both must run give from your own account before Wednesday 01 January 00:00 to obtain the marks for this lab exercise.

Your task is to add code to this function in practice_exam_q2.c:

// return how many 1 bits value contains
int practice_exam_q2(uint64_t value) {
    // PUT YOUR CODE HERE

    return 42;
}

Add code to the function practice_exam_q2 so that, given a uint64_t value, it returns how many 1 bits it contains. You should use bitwise operators to do this.

For example:

./practice_exam_q2 0x123456789abcdef0
practice_exam_q2(0x123456789abcdef0) returned 32
./practice_exam_q2 0xffffffffffffffff
practice_exam_q2(0xffffffffffffffff) returned 64
./practice_exam_q2 0x0000000000000000
practice_exam_q2(0x0000000000000000) returned 0
./practice_exam_q2 0x0000000400000000
practice_exam_q2(0x0000000400000000) returned 1
./practice_exam_q2 0x8000000000000001
practice_exam_q2(0x8000000000000001) returned 2

Use make(1) to build your code:

make    # or 'make practice_exam_q2'

When you think your program is working, you can use autotest to run some simple automated tests:

1521 autotest practice_exam_q2

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1521 lab10_practice_exam_q2 q2.c

Note, even though this is a pair exercise, you both must run give from your own account before Wednesday 01 January 00:00 to obtain the marks for this lab exercise.

In the files for this lab, you have been given practice_exam_q3.s, a MIPS assembler program that reads 2 numbers and then prints 42.

Add code to practice_exam_q3.s to make it equivalent to this C program:

// print the integers between x and y except 13
#include <stdio.h>

int main(void) {
    int x, y;

    scanf("%d", &x);
    scanf("%d", &y);

    int i = x + 1;
    while (i < y) {
        if (i != 13) {
            printf("%d\n", i);
        }
        i = i + 1;
    }

    return 0;
}

For example:

1521 spim -f practice_exam_q3.s
Loaded: /home/cs1521/share/spim/exceptions.s
5
8
6
7
1521 spim -f practice_exam_q3.s
Loaded: /home/cs1521/share/spim/exceptions.s
10
15
11
12
14
1521 spim -f practice_exam_q3.s
Loaded: /home/cs1521/share/spim/exceptions.s
5
14
6
7
8
9
10
11
12

Assumptions/Limitations/Clarifications

When you think your program is working, you can use autotest to run some simple automated tests:

1521 autotest practice_exam_q3

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1521 lab10_practice_exam_q3 q3.s

Note, even though this is a pair exercise, you both must run give from your own account before Wednesday 01 January 00:00 to obtain the marks for this lab exercise.