I have a problem with this code. It should do this:
gabriele -> grl
but instead of 3 characters it redouble the last one. Hence: gabriele -> grll
Why?
.data 0x10010000
nome: .asciiz "gabriele"
voc: .asciiz "aeiou"
st_nome:
.text 0x400000
main: la $s1, voc #address of voc in s1
la $s2, nome #address di nome in s2
li $t3, 0 #index name
li $t4, 0 #index vowel
li $t5, 0 #memory index
li $a1, 4 #max number of character
cerca_nom: lbu $t0, nome($t3)
beqz, $t0, fine
sc_voc2: lbu $t1, voc($t4)
beq $t0, $t1, ignora2
addi $t4, $t4, 1
beqz $t1, salva_n
j sc_voc2
salva_n: sb $t0, st_nome($t5)
addiu $t5, $t5, 1
bge $t5, $a1, prime
ignora2: addi $t3, $t3, 1
li $t4, 0
j cerca_nom
prime: li $t5, 0
la $t1, st_nome
lbu $t0, 0($t1)
sb $t0, st_nome($t5) #take the first character
addi $t5, $t5, 1
lbu $t0, 2($t1)
sb $t0, st_nome($t5) #take the third character
addi $t5, $t5, 1
lbu $t0, 3($t1)
sb $t0, st_nome($t5) #take the fourth character
fine:
In your cerca_nom loop you're removing the vowels from the name and storing the remaining characters ('g', 'b', 'r', 'l') at st_nome.
So now you've got 'gbrl' at st_nome.
Then you do:
st_nome[0] = st_nome[0] ; still 'gbrl'
st_nome[1] = st_nome[2] ; 'grrl'
st_nome[2] = st_nome[3] ; 'grll'
You're never overwriting st_nome[3], so there will still be an 'l' there.
Related
I'm currently working on a palindrome function in MIPS that takes a char array and returns 0 if it is not a palindrome, else 1. I've got everything seemingly working except for the part where I find data at index i and array.length-i-1. If someone could lead me in the right direction I'd really appreciate it.
Here's the java code I'm going off of:
int Palindrome(char[] s) {
for(int i = 0; i < (s.length / 2); i++) {
if(s[i] != s[s.length - 1 - i])
return 0;
}
return 1;
}
Here's the Palindrome function:
palindrome:
# Get length of array and store it in $t1
addi $sp, $sp, -8
sw $ra, 0($sp)
sw $a0, 4($sp)
li $t1, 0
lengthWhile:
lw $t2, 0($a0)
beq $t2, $zero, startPalindrome
addi $t1, $t1, 1
addi $a0, $a0, 4
j lengthWhile
startPalindrome:
div $t2, $t1, 2 # Stores a.length / 2 into $t2
add $t3, $t3, $zero # i value (0 - (a.length/2 - 1))
add $t4, $t4, $t1
subi $t4, $t4, 1 # a.length-1
# $t1 = a.length
# $t2 = a.length / 2
# $t3 = i
# $t4 = a.length - 1
palLoop:
bge $t3, $t2, exitLoop
sub $t4, $t4, $t3 # Puts a.length-1-i into $t4
sll $t5, $t3, 2
add $t6, $a0, $t5
lw $s1, 0($t6)
sll $s3, $t4, 2
add $t7, $a0, $s3
lw $s2, 0($t7)
bne $s1, $s2, return0
# Increase i and start loop again
addi $t3, $t3, 1
j palLoop
return0:
li $v0, 0
jr $ra
exitLoop:
li $v0, 1
jr $ra
Here's the main:
.data
charArray: .word 'a', 'b', 'c', 'd', 'c', 'w', 'a'
.text
main:
# Palindrom Function
la $a0, charArray
jal palindrome
move $a0, $v0
li $v0, 1
syscall
# Exit Program
li $v0, 10
syscall
Thank you in advance for any help. (To specify, palLoop is where I'm having trouble).
Not directly part of your question, but charArray: .word 'a', 'b', 'c', 'd', 'c', 'w', 'a' is really a word array containing a chatarter value, not a character array.
It looks like that will wok as you are using word array everywhere, however wont wok if you use a proper character array.
add $t3, $t3, $zero is t3 = t3 + 0 - what is t3 prior to that?
add $t4, $t4, $t1 - same comment
sub $t4, $t4, $t3 # Puts a.length-1-i into $t4 - will overwrite a.length-1 (t4) so is going not be right on the 2nd time through the loop.
This is the C code that i have been converted so far. it gives me some error that i have been included in the following code. i don't understand which part is wrong in this c to mips conversion?
char ch[10];
int i;
for (i = 0; i != 10; i++)
ch[i] = ch[i] – 32
.data
.text
li $v0 4
syscall
#$s1 = i, $s0 base address of ch
addi $s1, $0, 0 #i =0
addi $t0, $0, 10 #t0 = 10
loop: beq $t0, $s1, end
add $t1, $s1, $s0
lw $t2, 0($t1)
addi $t2, $t2, -32
sw $t2, 0($t1)
addi $s1, $s1, 1
j loop
end:
My output:
Runtime exception at 0x00400018: address out of range 0x00000000
From the C code you are converting a char type array and in MIPS you should use lb instead of lw.
In order to print out you need a main: label and also you should declare an array like .byte or .space
You should usesyscall 11 to print a character or syscall 4 to print
string.
I have added some of these mentioned above to your code hope it helps.
.data
#ch: .byte 'a','b','c','d','e'
ch: .space 10
.text
main:
li $v0, 8 #read character
li $a1, 10 #load the space
la $a0, ch
syscall
li $v0,11 #print character
syscall
li $v0,10 # exit program
syscall
addi $s1, $0, 0 #i = 0
addi $t0, $0, 10 # $t0 = 10
loop: beq $t0, $s1, end
add $t1, $s1, $s0
lb $t2, ch($t1)
addi $t2, $t2, -32
sb $t2, ch($t1)
addi $s1, $s1, 1
j loop
end:
I am trying to add numbers that are in base 5.
Im supposed to prompt the user for 2 separate base 5 number in the form XXXXXX.XXXXX, and then add them.
My current problem is that I am getting an error when I am loading the last digit into a register, so I can start the calculation.
please help! Thanks
.data
str: .space 13 # XXXXXX.XXXXX hold 12 chars + 0x00
str2: .space 13
sum: .space 14
printstr: .space 13
printstr2: .space 13
printsum: .space 14
message1: .asciiz "Enter a base 5 number A: "
message2: .asciiz "Enter a base 5 number B: "
message3: .asciiz "Sum of A and B: "
newline: .asciiz "\n"
.text
main:
#get number A
li $v0, 4
la $a0, message1
syscall
li $v0, 8
li $a1, 13
la $a0, str
syscall
li $v0, 4
la $a0, newline
syscall
#get number B
li $v0, 4
la $a0, message2
syscall
li $v0, 8
li $a1, 13
la $a0, str2
syscall
li $v0, 4
la $a0, newline
syscall
#pointer to input string A
la $s1, str
addi $s1, $s1, 12
#pointer to input string A
la $s2, str2
addi $s2, $s2, 12
#pointer to sum
la $s3, sum
addi $s3, $s3, 13
#other variables
li $t0, 0 # inital carry is 0
li $t1, 1 # counter for looping through string
li $t2, 5 # base 5
loop:
lb $t3, ($s1) ############################# PROBLEM HERE######
lb $t4, ($s2)
beq $t3, '.', next
beq $t4, '.', next
subi $t3, $t3, 0x30
subi $t4, $t4, 0x30
add $t5, $t3, $t4
add $t5, $t5, $t0
div $t5, $t2
mflo $t0
mfhi $t5
addi $t5, $t5, 0x30
sb $t5, ($s3)
subi $s1, $s1, 1
subi $s2, $s2, 1
subi $s3, $s3, 1
addi $t1, $t1, 1
ble $t1, 13, loop
addi $t0, $t0, 0x30
sb $t0, ($s3)
next:
subi $s1, $s1, 1
subi $s2, $s2, 1
#subi $s3, $s3, 1
addi $t1, $t1, 1
j loop
PRINT: #print the sum
exit:
li $v0, 10
syscall
You set up $s1 to point past str and decrement it backwards. Your loop: termination is the ble $t1,13,loop. When that completes, $s1 is pointing to the start of the .data section (i.e. 0x10010000).
But, then, you "fall through" to next: [probably wrong] and decrement $s1 so it has the value 0x1000ffff. Then, you do j loop so the fetch is now coming from an address one byte below the start of the .data segment (i.e. memory that does not exist)
That's the source of the crash. You probably need a jump inst after the ble to continue on to some other code.
But, also, when you do beq $t3,'.',next you go to next: and decrement both pointers. Unless you restrict your input there is no guarantee that both $s1 and $s2 both point to '.' at the same time, so you only want to decrement one of them. (e.g. suppose you had str: 12.3 and str2: 123.41)
So, you may need some code to align the two numbers with respect to their decimal points beforehand.
I have a little problem with my MIPS code, because this not work with "a", I explain better... If I write:
Heeeeello world --> I obtain this output "The 'e' has the biggest number of occurrences, 5"
hi Maaaaaark --> I obtain this output "The '' has the biggest number of occurrences, "
Can someone give me a solution? this is my code:
.data
m1: .asciiz "Give me a string: "
m2: .asciiz "\nThe letter '"
m3: .asciiz "' has the biggest number of occurrences, is present "
m4: .asciiz " times."
.align 2
myArray: .space 104
.text
.globl main
main:
li $v0, 4
la $a0, m1
syscall
addi $sp, $sp, -256
move $s0, $sp
move $a0, $sp
li $a1, 255
li $v0, 8
syscall
move $a0, $s0
jal check_case
move $a0, $v0
move $a1, $v1
jal analizza_stringa
move $a0, $v0
move $a1, $v1
jal stampa_risultato
end_program:
li $v0, 10
syscall
check_case:
move $t0, $a0
while:
lb $t1, ($t0)
beq $t1, 32, ignore_value_and_continue
beq $t1, 10, exit_check_case
bge $t1, 97, continue_check_case
bge $t1, 65, change_case
change_case:
addi $t2, $t1, 32
sb $t2, ($t0)
ignore_value_and_continue:
continue_check_case:
addi $t2, $t2, 1
addi $t0, $t0, 1
j while
exit_check_case:
move $v0, $t0
move $v1, $t2
jr $ra
analizza_stringa:
li $t1, 0
li $t2, 0
li $t3, 0
li $t4, 0
move $t7, $a0
sub $a0, $a0, $v1
sub $t7, $t7, $v1
while_string:
lb $t0, ($a0)
beq $t0, $zero, check_best
beq $t1, 32, ignore_value_and_continue2
ignore_value_and_continue2:
beq $t0, 10, check_best
subi $t3, $t0, 97
mul $t4, $t3, 4
move $t6, $t7
while_occorrenza:
beq $t1, 10, continue
lb $t1,($t6)
bne $t1, $t0, continue2
addi $t5, $t5, 1
continue2:
addi $t6, $t6, 1
j while_occorrenza
continue:
sw $t5, myArray($t4)
li $t5, 0
li $t3, 0
li $t1, 0
addi $a0, $a0, 1
j while_string
check_best:
li $t0, 0
lw $t1, myArray($t0)
addi $t0, $t0, 4
while_check_best:
beq $t0, 104, exit_check
addi $t5, $t5, 1
lw $t4, myArray($t0)
bge $t4, $t1, scambia
j continue_check
scambia:
blt $t4, $t2, continue_check
move $t2, $t4
add $t3, $t5, 97
continue_check:
addi $t0, $t0, 4
j while_check_best
exit_check:
move $v0, $t3
move $v1, $t2
jr $ra
stampa_risultato:
move $t0, $a0
li $v0, 4
la $a0, m2
syscall
li $v0, 11
move $a0, $t0
syscall
li $v0, 4
la $a0, m3
syscall
li $v0, 1
move $a0, $a1
syscall
li $v0, 4
la $a0, m4
syscall
jr $ra
So i have to write a bubblesort programm in mips using QtSpim for a class but i get an Exception 4 [Adress error in inst/data fetch]. I have searched in other topics and use the .align 2 directive before defining an array for 5 integers but it still isn't getting fixed.
Here's the code:
.text
.globl main
main:
la $t1, array #sets the base adress of the array to t1
la $a0, in_prompt
li $v0, 4
syscall
li $t2, 0 #init to 1
read_loop:
beq $t2, 5, read_key #break if t2 = 5
la $a0, num_prompt
li $v0, 4
syscall #"Give number"
#move $a0, $t2
#li $v0, 1
#syscall #current number to be read
li $v0, 5 #read int. 5 times
syscall
sw $v0, ($t1) #move input from v0 to the array
addi $t1, $t1, 4 #move t1 to the next position in the array
addi $t2, $t2, 1 #increment counter (t2) by 1
j read_loop
read_key:
la $a0, search_q
li $v0, 4
syscall #print query prompt
li $v0, 5
syscall
move $t3, $v0 #number we're looking for (KEY)
move $a0, $t1 #array to pass as arguement
jal bubblesort
move $a0, $v0 #move into a0 the sorted array
move $a1, $t3 #move the KEY into a1 as arguement
jal binarysearch
move $t1, $a0 #move into t1 the array
move $t0, $a1 #move into t0 the KEY
move $t3, $v0 #move into t3 the result of binarySearch
beq $t3, -1, not_found #if key was not found
move $a0, $t0
li $v0, 1
syscall
la $a0, found_pr
li $v0, 4
syscall
j print_array
not_found:
move $a0, $t0
li $v0, 1
syscall
la $a0, not_found_pr
li $v0, 4
syscall
j print_array
print_array:
li $t2, 1 #init to 1
print_loop:
beq $t2, 5, EXIT
lw $a0, ($t1)
li $v0, 1
syscall
addi $t1, $t1, 4
addi $t2, $t2, 1
j print_loop
EXIT:
li $v0, 10
syscall
##############binarysearch#################
binarysearch:
addi $sp, $sp, -24 #reserve space for 6 elements
sw $a0, 0($sp) #push a0 (array)into stack
sw $a1, 4($sp) #push a1(KEY) into stack
sw $s0, 8($sp) #push s0
sw $s1, 12($sp) #push s1
sw $s2, 16($sp) #push s2
sw $ra, 20($sp) #push ra
sw $s3, 24($sp) #push s3
li $s0, 0 #low = 0
li $s1, 4 #high = 4
while:
bgt $s0, $s1, exit_search #if low > high branch
move $a1, $s0 #move into a1 low
move $a2, $s1 #move into a2 high
jal calc_middle #jump to calc_middle
move $s2, $v0 #move into s2 the return value of calc_middle
lw $a0, 0($sp) #restore into a0 the 1st stack el(array)
lw $a1, 4($sp) #restore into a1 the 2nd stack el(KEY)
add $a0, $a0, $s2 #move the array to middle
lw $s3, ($a0) #load into s3 the a[middle]
beq $a1, $s3, exit_search_found #break if KEY == a[middle]
blt $a1, $s3, less_t_middle #if the key is less than the middle element
addi $s0, $s2, 1 #if the key is greater than the middle element set new low
j while
less_t_middle:
addi $s1, $s2, -1 #new high
j while
exit_search_found:
move $v0, $s2 #return found
lw $s0, 8($sp)
lw $s1, 12($sp)
lw $s2, 16($sp)
lw $ra, 20($sp)
addi $sp, $sp, 24
jr $ra
exit_search:
li $v0, -1 #return -1
lw $s0, 8($sp)
lw $s1, 12($sp)
lw $s2, 16($sp)
lw $ra, 20($sp)
addi $sp, $sp, 24
jr $ra
##############calc_middle##################
calc_middle:
add $a1, $a1, $a2
sra $a1, $a1, 1
move $v0, $a1
jr $ra
##############bubblesort###################
bubblesort:
addi $sp, $sp, -12
sw $s0, 0($sp)
sw $s1, 4($sp)
sw $s2, 8($sp)
li $s2, 4 #j = 5
li $s1, 0 #i = 0
outer_loop:
addi $s2, $s2, -1 #i = j - 1
blt $s2, $zero, exit_sort
inner_loop:
bgt $s1, $s2, outer_loop #if i > j - 1
lw $s3, 0($a0) #load into s3 the a[i]
lw $s4, 4($a0) #load into s4 the a[i+1]
bgt $s3, $s4, swap #if a[i] > a[i+1]
addi $s1, $s1, 1 #i++
j inner_loop
swap: move $s0, $s3 #tmp = a[i]
move $s3, $s4 #a[i] = a[i+1]
move $s4, $s0 #a[i+1] = tmp
addi $a0, $a0, 4 #point to the next element ????
addi $s1, $s1, 1 #i++
j inner_loop
exit_sort:
lw $s0, 0($sp)
lw $s1, 4($sp)
lw $s2, 8($sp)
addi $sp, $sp, 8
move $v0, $a0 #pass into v0 the sorted array
jr $ra
.data
.align 2
array: .space 20
in_prompt: .asciiz "Enter 5 numbers:\n"
num_prompt: .asciiz "Give number: "
search_q: .asciiz "what are you looking for?\n"
not_found_pr: .asciiz " not found in array: \n"
found_pr: .asciiz " found in array: \n"