系统调用 write 将第二个参数 (r1) 作为指向要打印的字符串的指针.您将一个指向整数的指针传递给它，这就是它不打印任何内容的原因，因为您传递给它的内存区域上没有 ASCII 字符.

The syscall write takes on the second argument (r1) as a pointer to the string you want to print. You are passing it a pointer to an integer, which is why it's not printing anything, because there are no ASCII characters on the memory region you are passing to it.

您将在下面找到一个使用系统调用写入的Hello World"程序.

Below you'll find a "Hello World" program using the syscall write.

.text
.global main
main:
        push {r7, lr}

        mov r0, #1
        ldr r1, =string
        mov r2, #12
        mov r7, #4
        svc #0

        pop {r7, pc}

.data
string: .asciz "Hello World\n"

如果你想打印一个数字，你可以使用 C 库中的 printf 函数.像这样:

If you want to print a number you can use the printf function from the C library. Like this:

.text
.global main
.extern printf
main:
        push {ip, lr}

        ldr r0, =string
        mov r1, #1024
        bl printf

        pop {ip, pc}

.data
string: .asciz "The number is: %d\n"

最后，如果你想用 syscall write 打印数字，你也可以实现一个 itoa 函数(一个将整数转换为字符串的函数).

Finally, if you want to print the number with the syscall write you can also implement a itoa function (one that converts an integer to a string).