MIPS 32 Assembly Programs

This repository contains a collection of MIPS 32 assembly programs which I did during taking Principles of Computer Systems course taught by Prof. Laleh Arshadi at Sharif University of Technology, Fall 2023. MIPS (Microprocessor without Interlocked Pipeline Stages) is a popular RISC (Reduced Instruction Set Computing) architecture commonly used in embedded systems and academic settings.

Programs

1. Q1-Equivalence

   • Description: Assuming that the variables f, g, and h, as well as the arrays A and B, are stored in the registers $s0, $s1, $s2, $s6, and $s7, and the address of the first element of arrays A and B is stored in $s6 and $s7 respectively. Write a MIPS program that is equivalent to

     g=g+h+B[4]
     g=g-A[B[4]]
     

2. Q2-Leap Year

   • Description: Write a program in MIPS that receives a number as input, representing a year, and checks whether it is a leap year or not. If it is a leap year, print 'YES'; otherwise, print 'NO'. The condition for a leap year is as follows:

   ((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)
   

   • Test Case:

    Input: 100
    Output: NO
    
    Input: 1400
    Output: NO
    
    Input: 1404
    Output: YES
   

3. Q3-base 16

   • Description: Write a program in MIPS that receives a number as input, and represents the input in base-16.
   • Test Case:

    Input: 167
    Output: a7
    
    Input: 175
    Output: af
   

4. Q4-chunk

   • Description: Write a program in MIPS that receives a number as input, and outputs bits 14:17 (inclusive) as a decimal number.
   • Test Case:

    Input: 143360
    Output: 1
    
    Input: 11166000
    Output: 3
   

5. Q5-java

   • Description: Write a subroutine in MIPS that is equivalent to this Java code below. Note that it must get inputs in $a0, $a1 and put the result in $v0 register.

     public class Main {
         public static int amin(int m, int n) {
             return 2 * m - n;
         }
     
         public static void main(String[] args) {
             int b = 2, c;
             int[] a = {2, 5, 3, 7, 1};
     
             for (int i = 0; i < 5; i++) {
                 if (a[i] > b)
                     c = amin(a[i], b);
                 else
                     c = 0;
                 System.out.println(c);
             }
         }
     }

6. Q6-parity

• Description: Write a program in MIPS that puts remainder of the register $s0 (mod 2) in the same register. You are not allowed to use any other registers. Hint: You may use sll, srl to find parity of register content.

7. Q7-sort

   • Description: let 3 relatively small numbers (abs of numbers is less than $2^{29}$) be in registers $s1, $s2, $s3. Write a MIPS program that sorts these numbers without using conditional instructions (i.e. bne, beq) and puts them in $t1, $t2, $t3 in increasing order. To do so, first write a macro that finds maximum of two numbers and solve the problem using the macro.

8. Q8-pie squared

   • Description: write a MIPS program that gets n from the user and calculates square of $\pi$ using following series: $$\frac{\pi^2}{6} = \sum_{i=1}^n \frac{1}{i^2}$$

9. Q9-nCr

   • Description: Write a MIPS program that gets n, r from input and calculates ${n \choose r}$ using following recursion: $${n\choose r} = {n-1 \choose r-1} + {n-1 \choose r}$$

10. Q10-statistical

• Description: Write a MIPS program that first gets n, and then gets n numbers from input, then returns their average and variance. Hint: to store numbers, use syscall 9

11. Q11-encryption

• Description: The only secure way of encryption is One Time Pad (OTP). In this method, the main string and a random string with same length are XOR together to make the encrypted string. write a MIPS program that gets seed (a string of length 4) and a string of maximum 20 byte length from input. Then make the random encryption key string, by repeatedly calling syscall 42. Let upperbound be 256 and seed be what user enters. At the end, print the encrypted string by XORing the input string and encryption key.

---

here is two advanced problems (simple projects maybe:))

12. Q00-BACKWARDS uppercase

• Description: Develop a MIPS assembly program that accepts a string as input and performs the following operations on it:

  • Utilize a subroutine to convert all lowercase letters within the string to uppercase letters, without requiring additional memory allocation.
  • Implement another subroutine to print the resulting string in reverse, starting from the last character.

It is important to note that the program should not rely on the syscall 9 instruction for obtaining user input. Furthermore, it should enforce a predetermined length limit on the input string, rejecting any strings that exceed this limit.

13. Q000-transpose matrix

• Description: Design a MIPS assembly program that requests an integer input, denoted as n satisfying the condition $n > 1$. In the event that the user provides an input that is not greater than $1$, the program prompts the user to enter a valid number again. After acquiring a suitable value for n, the program proceeds to execute the following operations:

  • Implement a subroutine that allocates an $n \times n$ memory space and arranges the numbers $1,2, \cdots ,n^2$ in rows within the allocated memory.

  • Create a subroutine that performs an in-place transposition of the matrix.

  • Output the resulting matrix row by row using a designated subroutine.

It is crucial to ensure that the program adheres to the specified requirements and executes the aforementioned subroutines in the correct sequence.

Getting Started

To run these MIPS assembly programs, you'll need the MARS (MIPS Assembler and Runtime Simulator) emulator. You can download it here.

Running a Program

1. Clone the repository to your local machine:

   git clone https://github.com/your-username/mips-assembly-programs.git

2. Open MARS and load the program:

   • Click on "File" > "Open" and select the MIPS assembly file (e.g., program_name.asm).

3. Assemble the program:

   • Click on "Run" > "Assemble" to assemble the program.

4. Run the program:

   • Click on "Run" > "Go" to execute the program.

Contributing

If you'd like to contribute to this repository by adding new programs or improving existing ones, please follow these steps:

1. Fork the repository.

2. Create a new branch:

   git checkout -b feature/new-program

3. Make your changes and commit them:

   git commit -m "Add new program: Program Name"

4. Push to the branch:

   git push origin feature/new-program

5. Open a pull request.

License

This project is licensed under the MIT License.

Happy coding!