Question

LAB: Procedure calls Given the following C program and the mapping of registers to variables, complete the MIPS implementation of Main. Do not im return θ; in main 0 . int Dif(int a, int b) f return a −b; \} int Sum(int a, int b) f return a+b; \} int main(){ int x r

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y; w=Sum(x,y); z=Dif(y,x); return 0; // Do not implement \} Hint: Use a0, a1 as arguments and v0 as return value, according to the register conventions. Ex: If the values of $s0 and $s1 are initialized in the simulator as: the results are stored in $ s 2 and $s3 : Note: Use the '+' button under the Registers display to initialize register values for $ so and $ \$1. 4514492643a72,0×3z777

Answer 1

The MIPS implementation of main involves setting arguments, calling functions, and storing return values using the MIPS calling convention with registers a0, a1 for arguments, and v0 for the return value.

Step-by-step explanation:

The MIPS implementation of the main function from C to MIPS Assembly requires understanding of the use of registers for arguments and return values as well as the calling convention. In MIPS, the a0 and a1 registers are used to pass arguments, and the v0 register is used to store the function return value.

In your main function:

1. Store the values of x and y into a0 and a1 respectively.
2. Call the 'Sum' function.
3. Store the return value of 'Sum' from v0 into s2 (w).
4. Store y and x into a0 and a1 with reversed order for the 'Dif' function's parameters.
5. Call the 'Dif' function.
6. Store the return value of 'Dif' from v0 into s3 (z).

Since the C function does not actually return any meaningful value, we can simply set the return value to 0 in the v0 register at the end.