For this and all programming assignments for this course, you are to write a MIPS assembly language
program that can be loaded and executed using the MARS simulator.
Arrays and Functions
For this assignment, you’ll be writing two functions. Below are the C++ signatures for the functions., as
well as a brief explanation of each.
void arprt(int arr[], int size, int perln) – Given the array arr having the given
size, display the values in the array. A newline should only be output for every perln values displayed,
and following the last value. Values displayed on the same line should be separated by a space. In other
words, output the values in the array, perln values per line of output.
int expos(int arr[], int size, int dest[]) – Given the array arr having the given
size, and an array dest that is at least as large as arr, copy from the arr array into the dest array only
those values in arr that are greater than zero. Return the number of values that were copied into dest.
Your functions are expected to adhere to the standard MIPS conventions for parameter passing,
returning values, and protecting registers used in the function.
Your main program will call upon these functions to process four arrays. These arrays will be defined
as follows:
.data
.align 2
.eqv size1,9
nums1: .word 12,13,25,66,102,111,234,53,26
.eqv size2,12
nums2: .word 44,55,22,33,44,77,77,44,33,99,21,99
.eqv size3,6
nums3: .word 21,32,44,112,43,99
pos: .space 48
Your main program will mainly just make function calls, as follows (shown in C++):
int nsize;
cout << “nums1:n”);
arprt(nums1,size1,4);
nsize = expos(nums1,size1,pos);
cout << “npositive values:n”);
arprt(pos,nsize,4)cout << “nnums2:n”);
arprt(nums2,size2,5);
nsize = expos(nums2,size2,pos);
cout << “npositive values:n”);
arprt(pos,nsize,5)
cout << “nnums3:n”);
arprt(nums3,size3,1);
nsize = expos(nums3,size3,pos);
cout << “npositive values:n”);
arprt(pos,nsize,1)
If your function is working correctly, your output should begin like this:
nums1:
12 13 25 66
102 111 234 53
26
positive values:
12 25 66 102
53 26
… (etc. for nums2 and nums3)
You are expected to follow all MIPS conventions for functions.
• Parameters are passed using the $a registers ($a0 is first parameter, etc.).
• Arrays are passed by reference. (Pass the base address of the array.)
• Register $v0 is used to provide the return value to the caller.
• The “jal” instruction is used to make the actual function call.
• The “jr $ra” instruction is used to return to the caller.
• Any registers (other than $t registers and $v0) changed inside the function, should be saved on
the stack on entry and restored on return.
It is important to realize that, since what is being passed to these functions is the base address of the
arrays, you can think of this as simply a pointer to the first element. You can then use pointer
manipulation, rather than indexing, to visit each element in the arrays.
You may want to review the example “ArraySumPointersFunction” you can find on attachment.
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