<schema-selection match-catalog="mybd" match-schema="mybd"/>
此代码编译但我的输出有一些错误。
在addi $ t5，$ t5，-32行，将大写的值设为小写。它使一切都变成大写。
这是测试输出。
.data
input:.space 80 #buffer space for input
built:.space 80 #buffer space for built string from looping
#string values to call when printing
message: .asciiz "Please enter a string:"
newline: .asciiz "\n"
ispaly: .asciiz "\n This is a palindrome"
notpaly: .asciiz "\n This is not a palindrome"
.text
main:
la $a0, message # user input message
li $v0, 4 #mips to print string
syscall #call return values
la $a0, input #users input
li $a1, 80 #allocating space for the buffer of size 80
li $v0, 8 #reading the buffer
syscall #call return values
secondinput:
la $t1,built #creating a new buffer string while going through the loop
loop:
lb $t5,($a0) #loading the byte into the buffer
beq $t5, 10, check # if it has a new line
bgt $t5, 47, digittest #and has value greater then ascii 47
jal dontbuild #if it is not then we increment to next character
digittest:
blt $t5, 58, dobuild #proceeding from above, if it is less then ascii 58(digits)
bgt $t5, 64, capital #and greater then ascii 64 we dont build it into our new buffer(built)
jal dontbuild #jump to dontbuild function
capital:
blt $t5, 91, dobuild #buffer being (built) is less than ascii 91 its a capital letter
bgt $t5, 96, punctuation #if its greater then 96 its is a lowercase
j dontbuild #jump to dontbuild
dobuild:
bgt $t5, 96, makelow #built value byte is already lowercase
j lower #go to lower function
punctuation:
blt $t5,123, dobuild #buffer being built has a value less then 123 and passed previous functions it is a capital and we make it lower
j dontbuild #otherwise we dont add to buffer(built)
makelow:
addi $t5,$t5, -32 #if value is lower subtract 32 to make it capital
j lower #jump to lower function and increment
lower:
sb $t5,($t1) #store the byte so it does not get modified
addi $a0,$a0, 1 #increment for comparison
addi $t1,$t1,1 #increment for comparison
j loop #go back up to loop
dontbuild:
addi $a0,$a0,1 #increment to next character
j loop #jump to loop
check:
la $t4, built #buffer that was built
sb, $zero,($a0) #store the byte in argument
addi $t1,$t1,-1 #decrement from the end of our $t1 register
loop2:
lb $t3,($t4) #load byte into temporary register
lb $t2,($t1) #load byte into temporary register
beq $t3,$t2,next #check if each byte is equal
j notp #if they are not go to not a palindrome
next:
jal test #if they are equal
addi $t4,$t4,1 #increment through the string
addi $t1,$t1,-1 #decrement through the string
j loop2 #go through the loop
j notp #if it runs into a non equal value its not a palindrome
test:
beq $t4,$t1,isp #if all values are equal it calls palindrome
addi $t1,$t1,-1
beq $t4,$t1,isp #do we need to check any other values
addi $t1,$t1,1
jr $ra #return to os
isp:
la $a0, input # the users input
li $v0, 4
syscall #call return values
li $v0, 4 #print a new line
la $a0, newline
syscall
la $a0,built
li $v0, 4
syscall
la $a0,ispaly #string that it is a palindrome
syscall #call return values
j exit #end
notp:
la $a0, input #users input
li $v0, 4
syscall #call return values
li $v0, 4 #print a new line
la $a0, newline
syscall
la $a0,built
li $v0, 4
syscall
la $a0, notpaly #string that it is not a palindrome
syscall #call return values
j exit
exit:
li $v0, 10 #end program
syscall #call return values
我需要的输出是 amanaplanacanalpanama
在ascii字符中，您必须添加32才能从大写变为小写 例如A = 65，所以65 + 32 = 97，其中= a。
当我尝试在我的代码中执行相反的操作时 subi $ t5，$ t5,32
我得到大写值相同的输出
如果我将其更改为
addi $ t5，$ t5,32
输出
Please enter a string:A man, a plan, a canal --Panama!
A man, a plan, a canal --Panama!
AMANAPLANACANALPANAMA
This is a palindrome
基本上每个小写的值都是一个正方形。
最后一个问题是我的测试循环不被视为递归。这是真的吗？
答案 0 :(得分：0)
在ascii字符中，您必须添加32才能从大写字母转到 小写，例如A = 65，所以65 + 32 = 97，= a。
你在两种情况下都减去32，而不是添加。 addi $t5,$t5, -32（添加-32）与subi $t5,$t5, 32相同（减去32）。
基本上每个小写的值都是一个正方形。
因为您要为小写字符添加32，并且最终会显示不可打印的字符，这些字符显示为正方形。
最后一个问题是我的测试循环不被视为递归。是 这是真的吗？
我不知道test在哪里循环。无论如何，你的代码中没有递归，只有循环。递归是指函数调用自身并且代码中没有函数。