Programming at the Hardware-Software Interface
You must follow the programming and documentation guidelines available in the Blackboard module Projects.
Important Notes:
(i) This is nota team project.
(ii) This project has two parts and both parts must be done in MAL. You must submit two MAL source files named p5a.mal and p5b.mal.
(iii) There is no two-day grace period for this assignment.
Description of Part (a)
In MAL an integer is represented using 32 bits. Assume that the bits are numbered right to left from 0 to 31. Thus, the rightmost bit is numbered 0 and the leftmost bit is numbered 31. We say that the bits 0 through 15 form the right halfand the bits 16 through 31 form the left halfof the integer.
You are required to write a MAL program that prompts a user for a positive decimal integer, reads the integer typed by the user and outputs the following values:
1. The total number of 1's in the right half of the binary representation of the integer.
2. The total number of 0's in the left half of the binary representation of the integer.
3. The highest power of 2 that evenly divides the integer .
4. The value of the largest digit in the decimal representation of the integer.
Example:Suppose the user types the decimal integer 1536. The 32-bit binary representation of 1536 is as follows:
0000 0000 0000 0000 0000 0110 0000 0000
For this example, the required answers are as follows:
1. The number of 1's in the right half of the binary representation of the given integer = 2.
2. The number of 0's in the left half of the binary representation of the given integer = 16.
3. The largest power of 2 that evenly divides the given integer = 93.
4. The value of the largest digit in the decimal representation of the given integer = 6.
Program outline:
The outline for your program for Part (a) must be the following.
1. Prompt the user for a positive integer.
2. Read the integer.
3. Compute the four quantities mentioned above and print the answers.
4. Stop.
Programming Suggestions:
1) MAL program must be in a file named p5a.mal.
2) Each time your program for Part (a) is executed, it should handle just one integer.
3) You may assume that the value typed by the user is a positive decimal integer. Thus, there is no need to do any error checking in this part.
4) There is no need to convert the integer to binary; when the integer is read in (using syscall), it is already in binary form.
5) Use bitwise operations to count the number of 1's (0's) in the right (left) half.
6) To find the highest power of 2 that divides the integer, count the number of 0's at the end of the binary representation or use successive divisions by 2.
7) To extract the decimal digits and compute the largest digit, use successive divisions by 10.
Description of Part (b)
In this part, you are required to write a MAL program that prompts the user for a line of textand reads the line typed by the user. If the line contains just white space characters your programshould simply output the message "Line contains only white space characters." and stop.Otherwise, your program should compute and output the following:
1. The number of non-whitespace characters in the line.
2. The number of words in the line.
3. The maximum length of a word in the line.
4. The minimum length of a word in the line.
5. The word of maximum length in the line. (If there are two or more words of maximum lengthin the line, then the program should print the word of maximum length that appears first inthe line.)
6. The word of minimum length in the line. (If there are two or more words of minimum lengthin the line, then the program should print the word of minimum length that appears first inthe line.)
Example: Suppose the line typed by the user is the following:
It was the best of times and it was the worst of times.
The answers for the above line are:
No. of non-whitespace characters: 43
No. of words: 13
Maximum length of a word: 6
Minimum length of a word: 2
Word of maximum length: times.
Word of minimum length: It
Note that the word of maximum length (6) is "times." (without the quotes), which includesthe punctuation mark at the end. (Recall that a word is any sequence of characters that does notinclude a whitespace character.) There are several words of minimum length (2) in the above text. The first such word is "It" (again, without the quotes).
Program outline:
The outline for your program for Part (b) must be the following.
1. Prompt the user for a line of text.
2. Read the line of text typed by the user.
1. If the line has only whitespace charactersprint the message "Line contains only white space characters" and stop.
2. Otherwise compute the quantities mentioned above and print the answers.
3. Stop.
Programming Suggestions:
1) MAL program must be in a file named p5b.mal.
2) It must have at least one function in addition to the main program.
3) Study Lecture 15 (arrays of character in MAL) before working on Part (b).
4) You may find it useful to write a function that returns information (e.g. starting and ending indices) about the next word.
5) A word is any sequence of characters that does not contain a whitespace character.
6) A whitespace character refers to a space, a tab or the newline character.
7) Any line of text typed by a user has at most 80 characters including the newline character.
8) End of any line is determined by the null character.
9) It is excepted to check whether the input line consists of just whitespacecharacters, no other error checks are needed.
10) Each time your program is executed, it should handle just oneline of text.
Some sample data to test your program:
Important Note: Some sample inputs that can be used to test your programsare given below. However, you should remember that when we compileand run your source files, we will use other data. Just because your programs work for the sample inputs given below,you shouldn't assume that they will work for all inputs.Therefore, you should test your programs thoroughly with otherinput values.
Example of program execution:
Part (a). Example 1.
unix2> /usr/local/bin/spim
.
. <--- Initial lines printed by spim.
.
(spim) read "p5a.mal"
(spim) run
Positive integer? 1536
No. of 1's in the right half = 2
No. of 0's in the left half = 16
Largest power of 2 = 9
Largest decimal digit = 6
(spim) quit
unix2>
Part (a). Example 2.
unix2> /usr/local/bin/spim
.
. <--- Initial lines printed by spim.
.
(spim) read "p5a.mal"
(spim) run
Positive integer? 123
No. of 1's in the right half = 6
No. of 0's in the left half = 16
Largest power of 2 = 0
Largest decimal digit = 3
(spim) quit
unix2>
Part (b). Example 1.
unix2> /usr/local/bin/spim
.
. <--- Initial lines printed by spim.
.
(spim) read "p5b.mal"
(spim) run
Text? A short line.
No. of non-whitespace characters: 11
No. of words: 3
Maximum length of a word: 5
Minimum length of a word: 1
Word of maximum length: short
Word of minimum length: A
(spim) quit
unix2>
Part (b). Example 2.
unix2> /usr/local/bin/spim
.
. <--- Initial lines printed by spim.
.
(spim) read "p5b.mal"
(spim) run
Text? This example contains five words.
No. of non-whitespace characters: 29
No. of words: 5
Maximum length of a word: 8
Minimum length of a word: 4
Word of maximum length: contains
Word of minimum length: This
(spim) quit
unix2>