Assignment 2

The file assign2.asm holds a partial program. The purpose of the program is to read in a list of 10 integers and then print them out. There are 4 functions in the program; 2 of which you are to complete.

Main: This function will call getdata and print. Main is complete and should not be changed.

Getdata: This function reads 10 integers and stores them into memory. There is one parameter ($a0) which holds the address of where the list of numbers is to be stored. Getdata calls the function printstr to print the prompt. Getdata is complete and should not be changed.

Printstr: This function is to print a string. There is one parameter ($a0) which holds the address of the string to print. You are to complete this function so it performs as required. This function is call from the getdata function and the print function.

Print: This function is to print the list of integers. The integers must all be on the same line of output and be separated by a comma and space (already in the data segment). See the example input and output below. This function must call the printstr function to print the comma string. Remember that as this function calls another, it must save and restore the $ra.

Specifics:

Use only the instructions covered to date.

Do not use pseudo-instructions. See the information under MARS for preventing the use of pseudo-instructions.

Make sure that your print function calls the printstr function correctly and that the stack is used correctly.

Documentation:

Comment the beginning of your programs with your name, class, and assignment number.

Comment every instruction.

Assignment submittal:

Upload your assembly language program (.asm file) using this link on Blackboard.

Hints on getting started:

Load the assign2.asm file into the MARS simulator

Write the code for printstr and make sure that it works correctly.

Write the code for print.

Sample input and output. Note there is no comma after the last number.

Enter a number 1

Enter a number 2

Enter a number 9

Enter a number 11

Enter a number 99

Enter a number 12

Enter a number 24

Enter a number 90

Enter a number 17

Enter a number 82

1, 2, 9, 11, 99, 12, 24, 90, 7, 82

MIPS Code File:

# add your name and comments

.data

.space 40 # set aside 40 bytes for 10 integers

prompt: .asciiz "Enter a number " # address 0x10010028

comma: .asciiz ", " # address 0x10010038

.globl main

.text

main:

lui $a0, 0x1001 # get start of data segment

jal getdata # call getdata function

lui $a0, 0x1001 # get start of data segment

jal print # call print function

ori $v0, $0, 10 # set command to exit

syscall # end program

# printstr

# paramters: $a0 holds address of string to print

# purpose: print the string parameter

printstr:

#to be completed

jr $ra

getdata:

addi $sp, $sp, -4 # allocate space on stack

sw $ra, 0($sp) # save $ra

ori $t1, $a0, 0 # address of array

lui $t1, 0x1001 #start of data

ori $a0, $a0, 0x0028 # address of prompt

ori $t0, $0, 10 # counter

top: beq $t0, $0, ret # while not 0

jal printstr # call function to print prompt

ori $v0, $0, 5 # set command to read integer

syscall # read int

sw $v0, 0($t1) # save int in memory

addi $t1, $t1, 4 # increment to next location

addi $t0, $t0, -1 # decrement counter

j top # repeat

ret: lw $ra, 0($sp) # restore return address

addi $sp, $sp, 4 # clean up stack

jr $ra # return from call

# print

# parameter: $a0 holds address of list in memory

# purpose: print the list separated by commas

print:

#to be completed

jr $ra