Computer Organization

week3_1.asm

.data

uStr: .asciiz 
	"Alpha","Bravo","China","Delta","Echo","Foxtrot","Golf","Hotel",
    "India","Juliet","Kilo","Lima","Mary","November","Oscar","Paper","Quebec",
    "Research","Sierra","Tango","Uniform","Victor","Whisky","X-ray","Yankee","Zulu"

lStr: .asciiz 
	"alpha","bravo","china","delta","echo","foxtrot","golf","hotel","india",
    "juliet","kilo","lima","mary","november","oscar","paper","quebec","research",
    "sierra","tango","uniform","victor","whisky","x-ray","yankee","zulu"

cOffset: .word
   0,6,12,18,24,29,37,42,48,54,61,66,71,76,85,91,97,104,113,120,126,134,141,148,154,161

numStr: .asciiz
	"Zero","First","Second","Third","Fourth","Fifth","Sixth","Seventh","Eighth","Ninth"

nOffset: .word 
	0,5,11,18,24,31,37,43,51,58
	
exitMsg: .asciiz "Bye bye!"

.text
.globl main
main: 
	li $v0, 12
	syscall
    # if the input charactor is '?' (ascii 63), then jump to exit section
	beq $v0, '?', exit 

	# if the input charactor less than '0' (ascii 48), it is symble
	blt $v0, '0', isSymble
	# if the input charactor less than ':' (ascii 58), it is number, because number charactor ascii range is 48 - 57
	blt $v0, ':', isNumber
    # if the input charactor less than 'A' (ascii 65), it is symble, because ascii (58 - 64) contains charactor :,;,<,=,>,?,@
	blt $v0, 'A', isSymble
    # if the input charactor less than '[' (ascii 91), it is upper charactor, because upper charactor ascii range is 65 - 90
	blt $v0, '[', isUpper
    # if the input charactor less than 'a' (ascii 97), it is symble, because ascii (91 - 96) contains charactor [,\,],^,_,`
	blt $v0, 'a', isSymble
    # if the input charactor less than '{' (ascii 123), it is lower charactor, because lower charactor ascii range is 97 - 122
	blt $v0, '{', isLower

	j isSymble

isUpper:
    # Get the number offset
	sub $t1, $v0, 'A'
    # Do number << 2
	sll $t1, $t1, 2

	la $s0, cOffset
	add $s0, $s0, $t1
    lw $s1, ($s0)

	# Get the number string according to the number offset value
    la $a0, uStr
	add $a0, $a0, $s1

	j printStr

isLower:
    # Get the number offset
	sub $t1, $v0, 'a'
	sll $t1, $t1, 2

	la $s0, cOffset
	add $s0, $s0, $t1
    lw $s1, ($s0)

	# Get the number string according to the number offset value
    la $a0, lStr
	add $a0, $a0, $s1

    j printStr

isNumber:
    # Get the number offset
	sub $t1, $v0, '0'
	sll $t1, $t1, 2

	la $s0, nOffset
	add $s0, $s0, $t1
    lw $s1, ($s0)

	# Get the number string according to the number offset value
    la $a0, numStr
	add $a0, $a0, $s1

    j printStr

printStr:
	li $v0, 4
	syscall
	li $a0, '\n'
	li $v0, 11
	syscall
	j main

isSymble:
    # load '*' to $a0 register
	li $a0, '*'
	li $v0, 11
	syscall
	li $a0, '\n'
	li $v0, 11
	syscall
	j main

exit:
	li $a0, '\n'
	li $v0, 11
	syscall
    # print string
	la $a0, exitMsg
	li $v0, 4
	syscall	

week3_2.asm

.data 

buffer: .space 1024
successMsg: .asciiz "Success! Location:"
failMsg: .asciiz "Fail!"
exitMsg: .asciiz "Bye bye!"

.text

main: 
	# Read search source string
	la $a0, buffer,
	li $a1, 1024
	li $v0, 8 
	syscall
	move $s0, $a0
	
   # Initial loop number
	add $a3, $zero, $zero
	add $t0, $zero, $zero

needleChar:
	# Read search needle charactor
	li $v0, 12
	syscall
	beq $v0, '?', exit
	move $a2, $v0

search:
	# If current iterate number equal to the max length, then jump to searchFail section
	beq $t0, $a1, searchFail
	la $a0, buffer
	add $t2, $a0, $t0
	lb $s1, ($t2)
	beq $s1, $a2, searchSuccess
    # Add 1 on the iterate number
	add $t0, $t0, 1
	j search

searchSuccess:
    la $a0, successMsg
    li $v0, 4
    syscall

    # Set the index value start from 1 rather than 0
    add $a0, $t0, 1
	li $v0, 1
    syscall

    add $a0, $zero, '\n'
    li $v0, 11
    syscall

	j needleChar

searchFail:
	la $a0, failMsg
    li $v0, 4
    syscall
    add $a0, $zero, '\n'
    li $v0, 11
    syscall

    # Reset loop number
	add $a3, $zero, $zero
	add $t0, $zero, $zero

	j needleChar

exit:
	li $a0, '\n'
	li $v0, 11
	syscall
    # print string
	la $a0, exitMsg
	li $v0, 4
	syscall