如何在mips程序集中迭代字符串 [英] How to iterate a string in mips assembly
本文介绍了如何在mips程序集中迭代字符串的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
所以我现在正在一个项目上,在这里我们必须输入一个字符串并将其转换为所有大写字母,然后再转换为小写字母(如果toUpper或toLower字节不是0的话).现在我仍在工作在大写部分(猜测小写几乎相同),但是当我遍历字符串以查找大写字母时或者在调用syscall进行打印时,我都陷入了困境.任何帮助将是巨大的.这是我到目前为止的内容:
So I am working on a project right now where we have to take in a string and convert it to all uppercase letters and then to lowercase letters if either the toUpper or toLower byte is anything but 0. Right now I am still working on the uppercase portion (guessing the lowercase will be almost the same) but I am getting stuck either when I am going through the string to find the letters that are uppercase or when I am calling the syscall to print. Any help would be great. Here's what I have so far:
.data
toUpper: .byte 1
toLower: .byte 0
string:
.asciiz " A long time ago in a Galaxy far, far away...."
# Your code goes below this line
origString:
.asciiz "Original string:\n"
toUpForwardStr:
.asciiz "\nConverted to upper-case:\nForward:\n"
toLowerForwardStr:
.asciiz "\nConverted to lower-case:\nForward:\n"
backwardStr:
.asciiz "Backward:"
.text
main:
# Function prologue
subu $sp, $sp, 24 # allocate stack space -- default of 24 here
sw $fp, 0($sp) # save caller's frame pointer
sw $ra, 4($sp) # save return address
addiu $fp, $sp, 20 # setup main's frame pointer
la $a0, origString #Print "Original String:"
addi $v0, $zero, 4
syscall
la $a0, string #Print string
addi $v0, $zero, 4
syscall
la $s0, toUpper
sb $s1, 0($s0) #toUpper stored in $s1
la $s0, toLower
sb $s2, 0($s0) #toLower stored in $s2
bne $s1, $zero, toUpperCase #Jump toUpperCase if toUpper ≠ 0
toUpperCase:
la $a0, toUpForwardStr #Print "Converted to upper-case:"
addi $v0, $zero, 4 # "Forward:"
syscall
la $s3, string #$s3 holds address to string
addi $s1, $zero, 0 #$s1 = i = 0
j upperCaseLoop #Goto upperCaseLoop
upperCaseLoop:
# Compute address of string[i]
add $t2, $s3, $s1 # $t2 = address of string[i]
lb $t3, 8($t2) # $t3 = elements[i]
beq $t3, $zero, upperDone # test if for loop is done
addi $t6, $zero, 96 #$t6 = 96 (lowercase letters)
bgt $t3, $t6, isLowercase1#If letter is lowercase goto isLowercase1
comeBackFromLowercaseIfs:
move $t3, $a0
addi $v0, $zero, 11
syscall
addi $s1, $s1, 1 # i++
j upperCaseLoop
upperDone:
bne $s2, $zero, toLowerCase #Jump toLowerCase if toLower ≠ 0
toLowerCase:
la $a0, toLowerForwardStr #Print "Converted to lower-case:"
addi $v0, $zero, 4 # "Forward:"
syscall
j done #The END!!
isLowercase1:
addi $t7, $zero, 123 #$t7 = 123
blt $t3, $t7, isLowercase2 #Goto isLowercase2
j comeBackFromLowercaseIfs #Go back to uppercaseLoop
isLowercase2:
addi $t3, $zero, -30 #changes letter to lowercase
j comeBackFromLowercaseIfs #Go back to uppercaseLoop
done:
# Epilogue for main -- restore stack & frame pointers and return
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
推荐答案
1个
move $t3, $a0
应该是
move $a0, $t3
2这
lb $t3, 8($t2)
应该是
lb $t3, 0($t2)
3本
addi $t3, $zero, -30 #changes letter to lowercase
应该是
addi $t3, $t3, -32 #changes letter to lowercase
这篇关于如何在mips程序集中迭代字符串的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文