CODEWITHSUNDEEP
assemblycharacterasciimips
user1698102
user1698102

Reputation: 127

Displaying Ascii values of characters

I am trying to make a program in which I can display ascii value of characters. The problem is it doesn't display the true ascii values. I am making this code in MIPS assembly which is very much similar to normal assembly language. Here is the code:

.data

User: .asciiz "Bush"
Line: .asciiz "\n"
Address: .word User

.text

main:
li $t0,1
li $t1,2
li $t2,3
li $t3,4
li $t4,5

lb $a0,User($0)
li $v0,1
syscall

la $a0,Line
li $v0,4
syscall

lb $a0,User($t0)
li $v0,1
syscall

la $a0,Line
li $v0,4
syscall

lb $a0,User($t1)

li $v0,1
syscall

la $a0,Line
li $v0,4
syscall

lb $a0,User($t2)

li $v0,1
syscall

la $a0,Line
li $v0,4
syscall

lb $a0,User($t3)

li $v0,1
syscall

la $a0,Line
li $v0,4
syscall

li $t1,-1
jal Length

j Exit

Length:

beq $a0,0,End
addi $t1,$t1,1
lb $a0,User($t1)
j Length

End:
move $a0,$t1
li $v0,1
syscall

jr $ra

Exit:
li $v0,10
syscall

What is the possible reason that It is not showing the true ascii values. Moreover When I try to make a program which finds the ascii values of all english alphabets, I get run time errors.It will be great deal to me if any one can help me with this.

Regards

Upvotes: 0

Views: 16287

Answers (2)

andreas karkotis
andreas karkotis

Reputation: 21

$s1 is ascii value

Show the character from register $s1

  li $v0, 11      #print character
  move $a0, $s1
  syscall

example: $s1="0"=0x30=48 Result: 0 Show the ascii value from register $s1 to decimal

li $v0, 1
move $a0, $s1 
 syscall

example: $s1="0"=0x30=48 Result: 48

Upvotes: 2

Jeff
Jeff

Reputation: 7674

What are you expecting it to do and what does it currently do? Here's the output for me:

66
117
115
104
0
4

If you want the actual letters to show up, use vector 11 instead of 1 for the syscall, which is the print character vector:

B
u
s
h

4

lb $a0,User($0)
li $v0,1
syscall

This loads one byte from the address of User and puts it into $a0. Then, it prints that value as an integer. The value at User is the value of the ASCII letter 'B', which is 66, hence it prints 66. Is this not correct?

la $a0,Line
li $v0,4
syscall

This puts the address of Line into $a0, and then it prints the string stored at that address. In this case it's a newline string, so a newline is printed. This is correct.

lb $a0,User($t0)
li $v0,1
syscall

This is almost identical to the first block, except now we have an address offset of $t0, which in this case is 1, meaning it loads the byte after the 'B' (the 'u'). The ASCII value of 'u' is 117 and that's what gets printed. Is this not correct?

This goes on for the first five characters of "Bush" (remember, the strings have been null-terminated with a 0-value), and the correct values seem to be printed, so you tell us what's wrong with it.

There's a bug with your Length routine, in that the first character isn't from User, but rather from Length. Change the ordering as such:

addi $t1,$t1,1
lb $a0,User($t1)
beq $a0,0,End
j Length

As for the alphabet stuff, please make a separate question and provide sufficient detail of the problem: what have you tried, what does it do, what is it supposed to do, things like that.

Upvotes: 2

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