检查 MIPS 中字符串中字符出现的次数？

Question

所以我正在编写一个简单的程序来打印自定义字符在自定义字符串中出现的次数。这是我的代码：

.data 
    command1:   .asciiz "Please enter a sentence "
    command2:   .asciiz "Please enter a character "
    count:      .word 10
    sentence:   .space 100
    character:  .space 4
    command3:   .asciiz " Character "
    command4:   .asciiz " appears in the sentence "
    command5:   .asciiz " times. "

.text
.globl main
main:
    li $t0, 100 #end var for loop
    li $t1, 0   #start var for loop
    li $t2, 0   #number of occurences

    la $a0, command1    #print 'please enter sentence'
    li $v0, 4
    syscall


    la $a0, sentence    #input sentence
    li $a1, 100
    li $v0, 8
    syscall

    la $a0, command2    #print 'please enter char'
    li $v0, 4
    syscall

    la $a0, character   #input character
    li $a1, 4
    li $v0, 8
    syscall

    la $s0, character
    lb $s1, ($s0)
    la $t3, sentence
    lb $a2, ($t3) #gets first char of sentence

loop:
    #addi $a2, $a2, 1
    beq $a2, $zero, end     #once reach end of char array, prints result
    beq $a2, $s1, something #if the char within sentence == comparing char
    addi $a2, $a2, 1        #increment char array
    j loop

something:              
    addi $t2, $t2, 1        #increments number of occurences of char 
end:
    la $a0, command3
    li $v0, 4
    syscall

    la $a0, character
    li $v0, 11
    syscall

    la $a0, command4
    li $v0, 4
    syscall

    la $a0 sentence
    li $v0, 4
    syscall

    #la $a0, $t2
    li $v0, 1
    move $a0, $t2
    syscall

    la $a0, command5
    li $v0, 4
    syscall

我的问题是，在我输入要与句子进行比较的字符后，程序进入无限循环（$s2 注册表不断更改值）并且没有打印任何内容。提前致谢！

Answer 1

您不能只加载字符串的第一个字符，递增它并期望获得下一个字符。您需要增加地址并为每个字符再加载一次。

所以像这样：

loop:
    beq $a2, $zero, end     #once reach end of char array, prints result
    beq $a2, $s1, something #if the char within sentence == comparing char
    addi $t3, $t3, 1
    lb $a2,($t3)        
    j loop

此外，您在递增 $t2 后不跳回到 loop 的事实似乎是错误的。

检查 MIPS 中字符串中字符出现的次数？

Check number of occurences of a char in a string in MIPS?

assembly

mips

qtspim