computer organization
c m s c 311  
s p r i n g   2 0 0 2  

Project #2 Primary

Corrections, etc.

Student Sample Output

One of the students in the class has already produced the primary output. You can use it as the expected output. Other students CAN post output, but NOT the code that produces it.

Student Output

Note: the executable should be run as: 

p2 -d 1000 -t 2000 < primary.input
Note: 1000 and 2000 could be replaced with other (reasonable) values. Also there is no "greater than" sign at the very end of the file (this may be removed when you read it)

You can still submit the project WITHOUT the primary input. However, it should minimally print out the addresses of the labels.

Primary Input

There may be bugs (send email to: clin@umd5.umd.edu). Check later for corrections. Comments will be removed (by me) in the actual tests.

NEW VERSION 

    .data

newline: string "\n"
mesg:    string "The current sum is: " 
mesg2:   string "Print: " 
mesg3:   string "The total is: " 
arr2:    bytes [3] 'f' 'u' 'n'
arr:     words [10] 1 2 3 4 5 6 7 8 9 10
value:   word 27

    .text
    jal printMesg       # print message
    addi $r26, $r0, 3
    la   $r27, arr2
    addi $r27, $r27, 1  # address of 'u'
    swi                 # print byte value -- 75 in base 16
    jal printNew        # print new line
    jal printMesg
    addi $r26, $r0, 3
    la   $r27, value
    swi                 # prints 00 (MSB of value 27)
    jal printNew        # print new line
    jal printMesg
    addi $r26, $r0, 3   # reset $r26 so that it is correct interrupt
    la   $r27, value    # reset $r27 because of subroutines
    addi $r27, $r27, 3  # add 3 to address
    swi                 # prints 1B (LSB of value 27)
    jal printNew        # print new line

    addi $r1, $r1, 0    # r1 stores sum
    addi $r2, $r2, 0    # r2 stores array index (times 4)
    addi $r3, $r3, 40   # r3 stores limit
L1: beq  $r2, $r3, DONE # jump to end of loop
    lw   $r4, arr($r2)  # val = arr[ i ]
    add  $r1, $r1, $r4  # sum = sum + val
    jal  printCurr
    jal  printNew        # print new line
    addi $r2, $r2, 4     # skip to next index
    j L1
DONE: addi $r26, $r0, 4       
      la   $r27, mesg3
      swi    
      addi $r26, $r0, 5
      addi  $r27, $r0, 1  # To print register 1, instead of register 27 
      swi                  # Print final value
      jal  printNew        # print new line
      j end                # Skip over the subroutines below

printMesg:
  addi $r26, $r0, 4
  la   $r27, mesg2
  swi
  jr $r31
  
printNew:  
  addi $r26, $r0, 4
  la   $r27, newline
  swi
  jr $r31

printCurr:  
  addi $r26, $r0, 4
  la   $r27, mesg
  swi
  addi $r26, $r0, 5
  addi $r27, $r0, 1  # To print register 1, instead of register 27 
  swi
  jr $r31

end:

Old VERSION 

    .data

newline: string "\n"
mesg:    string "The current sum is: " 
mesg2:   string "Print: " 
mesg3:   string "The total is: " 
arr2:    bytes [3] 'f' 'u' 'n'
arr:     words [10] 1 2 3 4 5 6 7 8 9 10
value:   word 27

    .text
    jal printMesg       # print message
    addi $r26, $r0, 3
    la   $r27, arr2
    addi $r27, $r27, 1  # address of 'u'
    swi                 # print byte value -- 75 in base 16
    jal printNew        # print new line
    jal printMesg
    addi $r26, $r0, 3
    la   $r27, value
    swi                 # prints 00 (MSB of value 27)
    jal printNew        # print new line
    jal printMesg
    addi $r26, $r0, 3   # reset $r26 so that it is correct interrupt
    la   $r27, value    # reset $r27 because of subroutines
    addi $r27, $r27, 3  # add 3 to address
    swi                 # prints 1B (LSB of value 27)
    jal printNew        # print new line

    addi $r1, $r1, 0    # r1 stores sum
    addi $r2, $r2, 0    # r2 stores array index (times 4)
    addi $r3, $r3, 40   # r3 stores limit
L1: beq  $r2, $r3, DONE # jump to end of loop
    lw   $r4, arr($r2)  # val = arr[ i ]
    add  $r1, $r1, $r4  # sum = sum + val
    jal  printCurr
    jal  printNew        # print new line
    addi $r2, $r2, 4     # skip to next index
    j L1
DONE: addi $r26, $r0, 4       
      la   $r27, mesg3
      swi    
      addi $r26, $r0, 5
      add  $r27, $r0, $r1
      swi                  # Print final value
      jal  printNew        # print new line
      j end                # Skip over the subroutines below

printMesg:
  addi $r26, $r0, 4
  la   $r27, mesg2
  swi
  jr $r31
  
printNew:  
  addi $r26, $r0, 4
  la   $r27, newline
  swi
  jr $r31

printCurr:  
  addi $r26, $r0, 4
  la   $r27, mesg
  swi
  addi $r26, $r0, 5
  add  $r27, $r0, $r1
  swi
  jr $r31

end:

The only new instruction is: la which stands for "load address".

la $rd, LABEL is not a real MIPS instruction. The equivalent (for small addresses) is addi $rd, $r0, LABEL. For larger addresses, you may need to use lui and ori to place both parts of the address.

The output should look like: 

Print: 75
Print: 00
Print: 1B
The current sum is: 1
The current sum is: 3
The current sum is: 6
The current sum is: 10
The current sum is: 15
The current sum is: 21
The current sum is: 28
The current sum is: 36
The current sum is: 45
The current sum is: 55
The total is: 55
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Last Modified: Sun Mar 3 22:54:00 EST 2002 		left up down right home

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