# A Comprehensive Guide to Adding Four Values in MIPS Assembly

In this guide, we provide a comprehensive walkthrough of adding four values in MIPS Assembly Programming. You'll step into the world of low-level programming and learn how to manipulate data using the MIPS assembly language. We break down a real-world code example, explaining each step in detail. Whether you're a beginner looking to understand assembly programming or a seasoned programmer seeking to master MIPS, this guide will help you grasp the essentials of adding values in this unique and powerful computing environment.

## Four-Value Addition in MIPS Assembly

Explore our comprehensive guide on adding four values in MIPS assembly to help your MIPS Assembly Language assignment. This step-by-step guide will equip you with the essential skills to tackle assembly programming tasks with confidence. Whether you're a novice or an experienced programmer, this resource will assist you in understanding and mastering four-value calculations in MIPS Assembly. Gain the knowledge to excel in low-level coding and build a strong foundation for tackling complex programming challenges. This guide is your key to becoming proficient in MIPS Assembly and handling assignments with ease.

## Block 1: `main` Function Initialization

``````assembly main: li \$t0, 500 li \$t1, 1500 li \$t2, 20 li \$t3, 3 ``````

In this block, the `main` function begins by initializing four integer values (`\$t0`, `\$t1`, `\$t2`, and `\$t3`) with specific values using the `li` (load immediate) instruction.

## Block 2: Stack Allocation and Parameter Saving

``````assembly addi \$sp, \$sp, -16 # reserve space on the stack for 4 values sw \$t3, 12(\$sp) sw \$t2, 8(\$sp) sw \$t1, 4(\$sp) sw \$t0, 0(\$sp) # save the parameters to the stack ``````

In this block, the code allocates space on the stack to store four integer values by decrementing the stack pointer (`\$sp`). Then, it saves the values of `\$t0`, `\$t1`, `\$t2`, and `\$t3` to the stack at specific offsets, effectively passing them as arguments to the `add4` function.

## Block 3: Function Call (`jal add4`)

``````assembly jal add4 # call the function ``````

This block makes a function call to `add4` using the `jal` (jump and link) instruction. This transfers control to the `add4` function.

## Block 4: Result Saving and Stack Cleanup

``````assembly move \$s1, \$v0 # Save the result addi \$sp, \$sp, 16 # Clean the stack ``````

After the `add4` function call, this block saves the result of the `add4` function (stored in `\$v0`) in the `\$s1` register. It then cleans up the stack by adding 16 to the stack pointer to release the previously allocated space.

## Block 5: Program Exit

``````assembly li \$v0, 10 # Exit the program syscall ``````

In this block, the program prepares to exit by loading `10` into register `\$v0`, which indicates a program exit syscall. The `syscall` instruction is used to perform the exit operation, terminating the program.

## Block 6: `add4` Function Definition

``````assembly add4: # int add4(int a, int b, int c, int d) ``````

This block serves as the definition of the `add4` function and specifies the function's signature.

``````assembly lw \$a0, 0(\$sp) # \$a0 = a; lw \$a1, 4(\$sp) # \$a1 = b lw \$a2, 8(\$sp) # \$a2 = c lw \$a3, 12(\$sp) # \$a3 = d add \$v0, \$a0, \$a1 # tmp = a + b add \$t0, \$a2, \$a3 # tmp2 = c + d add \$v0, \$v0, \$t0 # tmp += c + d ``````

This block loads the function arguments (`a`, `b`, `c`, and `d`) from the stack into registers `\$a0`, `\$a1`, `\$a2`, and `\$a3`, respectively. Then, it performs the addition of these values, first adding `a` and `b` and storing the result in `\$v0`, and then adding `c` and `d` to the result in `\$v0`.

## Block 8: Return

``````assembly jr \$ra # return tmp ``````

This block uses the `jr` instruction to return control to the calling function, which is the `main` function. The `\$ra` register (return address) contains the address of the instruction following the `jal` instruction in the `main` function, so execution continues from there.

## Conclusion

In conclusion, this guide has taken you through the intricacies of adding four values in MIPS Assembly Programming. You've learned how to initialize variables, allocate and manage the stack, make function calls, and perform arithmetic operations in a low-level computing environment. This knowledge serves as a valuable foundation for understanding assembly programming. Whether you're a beginner taking your first steps or a seasoned programmer seeking to broaden your skill set, the insights gained here will undoubtedly prove beneficial in your journey to mastering MIPS assembly.