Assignment 3: MIPS Assembly Procedure

CDA 4205 Computer Architecture 
Assignment 3: MIPS Assembly Procedure

1.    (10 pts) Implement the following C code in MIPS assembly. Show the contents of the stack after the function call to the function “compare” is made. Assume that the stack pointer is originally at address 0x7FFFFFFc.
int compare(int a, int b) {
if (sub(a, b) >= 0) return 1;
else return 0;
}
int sub(int a, int b) {
return a – b;
}
2.    (10 pts) Implement the following C code in the table in MIPS assembly. Suppose that fib_iter was called with n = 4, show the contents of the stack after the function call to the function “fib_iter” is made. Assume that the stack pointer is originally at address 0x7ffffffc.
int fib_iter(int a, int b, int n) {
if (n == 0) return b;
else return fib_iter(a+b, a, n-1);
} 

3.    (15 points) The following problems refer to a function f that calls another function func. The function declaration for func is “int func(int a, int b);”. The code for function f is as follows:
int f(int a, int b, int c) {
return func(func(a, b), c);
}
a)    Translate function f into MIPS assembly code, using the MIPS calling convention. If you need to use register $t0 through $t7, use the lower-numbered registers first.
b)    Right before your function f of Problem 3 returns, what do you know about contents of registers $ra, and $sp? Keep in mind that we know what the entire function f looks like, but for function func we only know its declaration.

4.    (15 points) The following problems refer to a function f that calls another function func. The function declaration for func is “int func(int a, int b);”. The code for function f is as follows:
int f(int a, int b, int c) {
return func(a, b) + func(b, c);
}
a)    Translate function f into MIPS assembly code, using the MIPS calling convention. If you need to use register $t0 through $t7, use the lower-numbered registers first.
b)    Right before your function f of Problem 4 returns, what do you know about contents of registers $ra, and $sp? Keep in mind that we know what the entire function f looks like, but for function func we only know its declaration.

5.    (20 points) Write a program in MIPS assembly language to convert a positive integer decimal string to an integer. Your program should expect register $a0 to hold the address of a null‐terminated string containing some combination of the digits 0 though 9. Your program should compute the integer value equivalent to this string of digits, then place the number in register $v0. If a nondigit character appears anywhere in the string, your program should stop with the value ‐1 in register $v0.

6.    (20 points) Repeat problem 5 with convert a string of hexadecimal digits to an integer.


    Submission Requirements
    Your solutions must be in a single file with a file name yourname-hw1.
    If scanned from hand-written copies, then the writing must be legible, or loss of credits may occur.
    Only submissions via the link on Canvas where this description is downloaded are graded. Submissions to any other locations on Canvas will be ignored.
    Late submissions are accepted for a maximum of 3 late days with 20% assignment credit off as late penalization. Assignments submitted after 3 late days will not be accepted.