Question

我想翻译一个计算从1到n之和的java代码到arm程序集，我想知道我是否正确翻译它？

这是我正在翻译的java代码的代码：

 int sum = 0 ;
 int num = 10; 
 int count = 1 ;
 while ( count <= num )
 {
  sum += count ; 
  count++ ;
 }
 System.out.println(sum);

到目前为止，这是我的手臂汇编代码：

    MOV r1, #0      ;store sum
    MOV r2, #10     ;number to count to
    MOV r3, #1      ;starting count

start_while:            ;start while loop
    CMP r3, r2      ;while count is less than number
    ADD r1, r1, r3  ;add count to sum
    ADD r3, r3, #1  ;increment count
    BNE start_while     ;end while loop
    ;print sum???

我是否正确翻译了while循环，如何打印总和？对不起我对手臂组装比较陌生，所以我不知道我做得对不对。

Answer 1

while（）通常翻译如下：

_start:
if (!condition) jump to _end
    ; do stuff inside the while loop
    jump to _start
_end:

所以你的循环看起来像这样：

    MOV r1, #0      ;store sum
    MOV r2, #10     ;number to count to
    MOV r3, #1      ;starting count

start_while:        ; start while loop
    CMP r3, r2      ; jump below while block if while condition is
    BGT end_while  ; not true anymore ( "<= 10" gets ">10")
    ADD r1, r1, r3  ;add count to sum
    ADD r3, r3, #1  ;increment count
    B start_while       ;go on with loop (no condition here)
end_while:
    ;print sum???

将Java代码转换为ARM程序集？

1 个答案: