Week 09 Weekly Test Questions

Test Conditions

These questions must be completed under self-administered exam-like conditions. You must time the test yourself and ensure you comply with the conditions below.

You may access this language documentation while attempting this test:

You may also access manual entries (the man command).

Any violation of the test conditions will results in a mark of zero for the entire weekly test component.

Set up for the test by creating a new directory called test09, changing to this directory, and fetching the provided code by running these commands: 

mkdir test09
cd test09
1521 fetch test09

Or, if you're not working on CSE, you can download the provided code as a zip file or a tar file.

weekly test question:
Create An add Instruction

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

// return the MIPS opcode for add $d, $s, $t
uint32_t add(uint32_t d, uint32_t s, uint32_t t) {

    return 42; // REPLACE WITH YOUR CODE

}

The function add is given the operands for a MIPS add instruction . Add code so that it returns the opcode for that instruction. Reminder the bit pattern for MIPS add instruction is:

Assembler Description C Bit Pattern
add $d, $s, $t add d = s + t 000000ssssstttttddddd00000100000

This is how your code should behave

./add 17 19 3
add(17, 19, -3) returned  0x02638820
./add 9 27 12
add(9, 27, 42) returned 0x036c4820

Use make(1) to build your code:

make    # or 'make add'
Assumptions/Limitations/Clarifications

  • You may define and call your own functions if you wish.

  • You are not permitted to change the main function you have been given, or to change add' prototype (its return type and argument types).

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

1521 autotest add
When you are finished working on this exercise you must submit your work by running give: 
give cs1521 test09_add add.c

weekly test question:
Print A String

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

void put_string(char *s) {

   // PUT YOUR CODE HERE

}

The function put_string is given a string. It should write the string to stdout followed by a newline. It should use the fputc function do this. You are not permitted to use any other function. 

./put_string hello
calling put_string("hello"):
hello
./put_string 'good bye'
calling put_string("good bye"):
good bye

Use make(1) to build your code:

make    # or 'make put_string'
Assumptions/Limitations/Clarifications

  • You may define and call your own functions if you wish.

  • You are not permitted to change the main function you have been given, or to change put_string' prototype (its return type and argument types).

  • You are not permitted to use printf, puts, fputs or write.

  • You are not permitted to use C library function other than fputc.

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

1521 autotest put_string
When you are finished working on this exercise you must submit your work by running give: 
give cs1521 test09_put_string put_string.c

weekly test question:
Read A Line

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

// print a line from stream using fgetc (only)
// reads  in at  most one less than size characters from stream and stores them into the
// buffer pointed to by s.  Reading stops after an EOF or a newline.  If a newline is read, it  is
// stored  into  the buffer.  A terminating null byte ('\0') is stored after the last character in the buffer.
void get_string(char *s, int size, FILE *stream) {

    // PUT YOUR CODE HERE

}

The function get_string should read a line of input from the specified stream.

More precisely it should: read in at most one less than size characters from stream and store them into the buffer pointed to by s. Reading stops after an EOF or a newline. If a newline is read, it is stored into the buffer. A terminating null byte ('\0') is stored after the last character in the buffer

For example:

./get_string 12
calling get_string(s, 12, stdin):
hello
s now contains 'hello
'
./get_string 16
calling get_string(s, 16, stdin):
good bye
s now contains 'good bye
'
./get_string 5
calling get_string(s, 5, stdin):
hello
s now contains 'hell'

Use make(1) to build your code:

make    # or 'make get_string'
Assumptions/Limitations/Clarifications

  • You may define and call your own functions if you wish.

  • You are not permitted to change the main function you have been given, or to change get_string' prototype (its return type and argument types).

  • You are not permitted to use fscanf fgets, read.

  • You are not permitted to use C library function other than fgetc.

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

1521 autotest get_string
When you are finished working on this exercise you must submit your work by running give: 
give cs1521 test09_get_string get_string.c

Submission

When you are finished each exercise make sure you submit your work by running give.

You can run give multiple times. Only your last submission will be marked.

Don't submit any exercises you haven't attempted.

If you are working at home, you may find it more convenient to upload your work via give's web interface.

Remember you have until Wednesday 01 January 00:00 to complete this test.

Automarking will be run by the lecturer several days after the submission deadline for the test, using test cases that you haven't seen: different to the test cases autotest runs for you.

(Hint: do your own testing as well as running autotest)

Test Marks

After automarking is run by the lecturer you can view it here the resulting mark will also be available via via give's web interface or by running this command on a CSE machine: 

1521 classrun -sturec

The test exercises for each week are worth in total 1 marks.

The best 6 of your 8 test marks for weeks 3-10 will be summed to give you a mark out of 9.