CSC263 Computer Org & Arch I - Memory Access Homework Answers

Homework Answers: Memory Access

```
lui    $t1, 0x1001
```

Any of the following will work:

     addi    $t1, $t1, 0x0c
     addi    $t1, $t1, 12
     ori     $t1, $t1, 0x000c

     lui     $t1, 0x1001
     ori     $t1, $t1, 0x002c

0x10010000
0x10010004
0x10010008

     ori     $t1, $t0, 8
          -- or --
     addi    $t1, $t0, 8

```
     sw      $t2, 4($t0)
```
```
     lb      $t3, 11($t0)
```

     lw      $t3, 4($t0)
     addi    $t3, $t3, 1
     sw      $t3, 4($t0)

     lw      $t1, length
     lw      $t2, width
     mult    $t1, $t2
     mflo    $t3
     sw      $t3, area

     lw      $a0, area
     li      $v0, 1
     syscall

     lui     $t0, 0x1001
     lw      $t1, 0($t0)
     lw      $t2, 4($t0)
     mult    $t1, $t2
     mflo    $t3
     sw      $t3, 8($t0)

     lui     $t0, 0x1001
     lw      $a0, 8($t0)
     li      $v0, 1
     syscall

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     move    $t3, $t0               # addr of nums
loop:
     li      $v0, 4                 # code to print string
     ori     $a0, $t0, 508          # addr of prompt
     syscall
     li      $v0, 5                 # code to read an int
     syscall
     sw      $v0, 0($t3)            # store the int in the array
     addi    $t3, $t3, 4            # move to next array element
     addi    $t2, $t2, 1            # increment loop counter
     blt     $t2, $t1, loop         # keep looping till $t2 == 100

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     move    $t3, $t0               # addr of nums
loop:
     li      $v0, 4                 # code to print string
     ori     $a0, $t0, 508          # addr of prompt
     syscall
     li      $v0, 5                 # code to read an int
     syscall
     beqz    $v0, done              # if user enters zero, stop reading
     sw      $v0, 0($t3)            # store the int in the array
     addi    $t3, $t3, 4            # move to next array element
     addi    $t2, $t2, 1            # increment loop counter
     blt     $t2, $t1, loop         # keep looping till $t2 == 100
done:
     sw      $t2, 404($t0)          # store number of numbers entered in count

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     move    $t3, $t0               # addr of current array element
     li      $v0, 1                 # syscall code to print int
loop:
     bge     $t2, $t1, done
     lw      $a0, 0($t3)            # current array element in $a0
     syscall                        # print current array element

     addi    $t2, $t2, 1            # increment loop counter
     addi    $t3, 4                 # move down to next array element
     b       loop
done:

     lui     $t0, 0x1001
     li      $t1, 50                # loop limit
     move    $t2, $0                # loop counter
     move    $t3, $t0               # addr of current array element
     li      $v0, 1                 # syscall code to print int
loop:
     bge     $t2, $t1, done
     lw      $a0, 0($t3)            # current array element in $a0
     syscall                        # print current array element

     addi    $t2, $t2, 1            # increment loop counter
     addi    $t3, 8                 # move down two array elements
     b       loop
done:

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     move    $t3, $t0               # addr of current array element
     lw      $t4, 0($t0)            # first element is largest so far
loop:
     bge     $t2, $t1, done
     lw      $t5, 0($t3)            # current array element in $t5
     ble     $t5, $t4, nobig        # check for bigger than so far
     move    $t4, $t5               # save new biggest
nobig:
     addi    $t2, $t2, 1            # increment loop counter
     addi    $t3, 4                 # move to next array element
     b       loop
done:
     li      $v0, 1
     move    $a0, $t4
     syscall                        # print largest

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     move    $t3, $t0               # addr of first array element
     add     $t3, 396               # addr of last array element
     li      $v0, 1                 # syscall code to print int
loop:
     bge     $t2, $t1, done
     lw      $a0, 0($t3)            # current array element in $a0
     syscall                        # print current array element

     addi    $t2, $t2, 1            # increment loop counter
     addi    $t3, $t3, -4           # move back to prev array element
     b       loop
done:

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     move    $t3, $t0
     ori     $t3, $t3, 408          # $t3 is addr of mychars
loop:
     li      $v0, 4                 # code to print string
     ori     $a0, $t0, 525          # addr of prompt
     syscall
     li      $v0, 12                # code to read a char
     syscall
     sw      $v0, 0($t3)            # store the int in the array
     addi    $t3, $t3, 1            # move to next array element
     addi    $t2, $t2, 1            # increment loop counter
     blt     $t2, $t1, loop         # keep looping till $t2 == 100

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     addi    $t3, $t0, 408          # addr of mychars
loop:
     li      $v0, 11                # code to print a char
     lbu     $a0, 0($t3)            # load char from array into $a0
     syscall
     addi    $t3, $t3, 1            # move to next array element
     addi    $t2, $t2, 1            # increment loop counter
     blt     $t2, $t1, loop         # keep looping till $t2 == 100

     lui     $t0, 0x1001
     li      $t1, 100               # loop limit
     move    $t2, $0                # loop counter
     addi    $t3, $t0, 408          # addr of mychars
     li      $t4, 0x61              # ascii code for 'a'
     ori     $t5, $0, 0             # $t5 = 0, count of a's
loop:
     lbu     $t6, 0($t3)            # load array element
     bne     $t6, $t4, noa          # jump around if char is not a
     addi    $t5, $t5, 1            # add to number of a's
noa:
     addi    $t3, $t3, 1            # move to next array element
     addi    $t2, $t2, 1            # increment loop counter
     blt     $t2, $t1, loop         # keep looping till $t2 == 100

     move    $v0, 1                 # code to print an int
     move    $a0, $t5               # print num of a's
     syscall