.data

mainNumPhrases:
        .word  3

mainPhrases:
        .word  mainPhrase1
        .word  mainPhrase2
        .word  mainPhrase3

mainPhrase1:
        .asciiz "A man, a plan, a canal, Panama!"
        .asciiz "bYe"
mainPhrase2:
        .asciiz "   CSc252 -- Computer Organization  "
mainPhrase3:
        .asciiz "            Three Tabs To StarT This Line    "

mainOriginalStr:
        .asciiz "main: The original string:\n"
mainFinalStr:
        .asciiz "main: The final string:\n"
mainTotalStr:
        .asciiz "main: Total character count: "

mainNewline:
        .asciiz "\n"

.text
main:
         # Function prologue -- even main has one
         subu  $sp, $sp, 24       # allocate stack space
         sw    $fp, 0($sp)        # save frame pointer of caller
         sw    $ra, 4($sp)        # save return address
         addiu $fp, $sp, 20       # setup frame pointer of main

         la    $t0, mainNumPhrases
         lw    $s0, 0($t0)        # $s0 = mainNumPhrases

         # skip everything if there are no phrases
         beq   $s0, $zero, mainDone

         # for i = 0 to mainNumPhrases - 1
         #   print phrase
         #   call convert
         addi  $s1, $zero, 0      # $s1 = i
         la    $s2, mainPhrases   # $s2 = mainPhrases[i]
         lw    $s3, 0($s2)        # $s3 = address of current phrase
         addi  $s4, $zero, 0      # $s4 = character count = 0

mainLoopBegin:
         # if i < mainNumPhrases
         slt   $t3, $s1, $s0      # $t3 = i < mainNumPhrases
         beq   $t3, $zero, mainLoopEnd

         # print the current phrase
         la    $a0, mainOriginalStr
         addi  $v0, $zero, 4
         syscall
         addi  $a0, $s3, 0        # $a0 = address of current phrase
         addi  $v0, $zero, 4
         syscall
         la    $a0, mainNewline
         addi  $v0, $zero, 4
         syscall

         # Startup Sequence:
         addi  $a0, $s3, 0        # $a0 = address of current phrase
         jal   convert
         # Clean up: get count of characters
         add   $s4, $s4, $v0      # $s4 += count

         # print the modified string
         la    $a0, mainFinalStr
         addi  $v0, $zero, 4
         syscall
         addi  $a0, $s3, 0
         addi  $v0, $zero, 4
         syscall

         # print a newline to terminate line and a blank line
         la    $a0, mainNewline
         addi  $v0, $zero, 4
         syscall
         syscall

         addi  $s1, $s1, 1        # i++
         addi  $s2, $s2, 4        # $s2 = address of next phrase
         lw    $s3, 0($s2)        # $s3 = next phrase
         j     mainLoopBegin

mainLoopEnd:
         # print the total character count
         la    $a0, mainTotalStr
         addi  $v0, $zero, 4
         syscall
         addi  $a0, $s4, 0
         addi  $v0, $zero, 1
         syscall
         la    $a0, mainNewline
         addi  $v0, $zero, 4
         syscall

mainDone:# Epilogue for main -- restore stack & frame ptrs & return
         lw    $ra, 4($sp)        # get return address from stack
         lw    $fp, 0($sp)        # restore frame pointer of caller
         addiu $sp, $sp, 24       # restore stack pointer of caller
         jr    $ra                # return to caller

.data
printLineNewline:
         .asciiz "\n"
.text
printLine:
         # Function prologue
         subu  $sp, $sp, 24       # allocate stack space -- default of 24 here
         sw    $ra, 4($sp)        # save return address
         sw    $fp, 0($sp)        # save frame pointer of caller
         addiu $fp, $sp, 20       # setup frame ptr for printLine


         # for (i = $a0; i <= $a1; i++)
         #    print character at location i
         add   $t0, $zero, $a0    # i = $t0 = $a0
printLineLoopBegin:
         # loop stops when i > $a1
         slt   $t2, $a1, $t0      # $t2 = $a1 < i
         bne   $t2, $zero, printLineLoopEnd
         lb    $a0, 0($t0)        # $a0 = character at array[i]
         addi  $v0, $zero, 11
         syscall
         addi  $t0, $t0, 1        # i++
         j     printLineLoopBegin

printLineLoopEnd:
         la    $a0, printLineNewline
         addi  $v0, $zero, 4
         syscall

printLineDone:
         # Epilogue for printLine -- restore stack & frame pointers
         lw    $ra, 4($sp)        # get return address from stack
         lw    $fp, 0($sp)        # restore frame pointer of caller
         addiu $sp, $sp, 24       # restore stack pointer of caller
         jr    $ra                # return to caller

# Your code goes below this line

.data

.text
convert:            # Function prologue
    addiu   $sp, $sp, -24
    sw  $fp, 0($sp)
    sw  $ra, 4($sp)
    sw  $a0, 8($sp) # Save the parameter
    addi    $fp, $sp, 20

    add $t0, $a0, $zero # $t0 = the memory address of the first character in the string.
    addi    $t4, $zero, 0   # $t4 = 0 (counts the number of characters in the string).
    lb  $t5, ($t0)  # $t5 = byte from memory address

nextChar:
    lb  $t1, ($t0)  # $t1 = byte from memory address
    beqz    $t1, strEnd     #
    addi    $t3, $0, 0x61
    sub     $t2, $t1, $t3
    bgez    $t2, l1
    add     $t1, $t1, 32
    sb  $t1, ($t0)

    addi    $t4, $t4, 1 # $t4++

    # Startup Sequence
    add $a0, $t5, $zero
    add $a1, $t1, $zero
    jal printLine
l1:
    addi    $t9, $0, 9
    beq $t1, $t9, jumpIt
    addi    $t9, $t9, 1
    beq $t1, $t9, jumpIt
    j   gotoNext
jumpIt:
    addi $t5, $t5, 1
gotoNext:
    add     $t0, $t0, 1
    j   nextChar

strEnd:
    add $v0, $t4, $zero

# Function epilogue -- restore stack & frame pointers and return
lw $a0, 8($sp) # restore original value of $a0 for caller
lw $ra, 4($sp) # get return address from stack
lw $fp, 0($sp) # restore the caller's frame pointer
addiu $sp, $sp, 24 # restore the caller's stack pointer
jr $ra # return to caller's code