Question

将c ++代码更改为mips时会遇到一些问题。

但是当我编译它时，该程序被卡在最里面的for循环中而无法退出。但是，我确定我每回合都会增加j，这是我可能犯的错误。

仅供参考，错误消息显示在sw $t6, 0($t8)中。它说运行时异常。地址超出范围。 c ++代码

void intToRoman(int num) {
  int index = 0;
  for (int i = 0; num > 0; ++i) {
    int count = 0;
    //deduct from the biggest radix for any many number of times as possible
    while (num >= roman_radix[i]){
      num -= roman_radix[i];
      count++; //record the number of each roman symbol of
              //roman_radix[i]
    }
    //write roman symbols of roman_radix[i] into roman
    for (; count > 0; --count){
      for (int j = 0; j < roman_offset[i]; j++){
        char temp = roman_symbol[roman_start[i] + j];
        roman[index++] = temp;
      }
    }
  }
}

我的MIPS代码

  # $a1 is num
intToRoman: 
add $t0 ,$zero, $zero #index
add $t1 ,$zero, $zero #i
add $t2 ,$zero, $zero #j

forlp1:
add $t7, $zero, $zero #count
sll $t3 ,$t1 ,2 
add $t3, $t3, $s0
lw $t4, 0($t3) #$t4 = roman radix[i]

whilelp:
sub $t6,$a1, $t4    # $t6 = num - roman_radix[i]  
bltz $t6, whileexit
add $t7, $t7, 1
add $a1, $t6, $zero
j whilelp
whileexit:

sll $t3 ,$t1 ,2  
add $t3, $t3, $s2  #$s2 is address of roman start array
lw $t4, 0($t3)
sll $t3 ,$t1 ,2 
add $t3, $t3, $s3   #$s3 is address of roman offset array
lw $t5, 0($t3) 

forlp2:
forlp3:
add $t6, $t4, $t2 # $t6 is romanstart[i]+j

sll $t3 ,$t6 ,2 
add $t3, $t3, $s1 #$s1 is address of roman symbol array
lw $t6, 0($t3)

sll $t8 ,$t0 ,2 
add $t8, $t8, $s4  #$s1 is address of roman array
sw $t6, 0($t8)  #  roman[index++] = temp;

add $t0, $t0, 1
add $t2, $t2, 1    # count++
beq $t2, $t5, forlp3exit
j forlp3

forlp3exit:
sub $t7, $t7, 1
blez $t7, forlp2exit
j forlp2
forlp2exit:

blez $a1, forlp1exit
add $t1 ,$t1, 1 
j forlp1
forlp1exit:

在mips中更改c ++代码罗马自然转换器

0 个答案: