如何获取存储在字符串中的输入 - 程序集

问：

我想编写一个程序集代码，打印“Hello， World！”，然后读取用户的输入，然后打印该输入。获取输入是正确的，但我无法打印它（或打印旧值）。 法典：

.global _start
.intel_syntax noprefix

_start:

    # Write
    mov rax, 1          # syscall number for sys_write
    mov rdi, 1          # file descriptor 1 (stdout)
    lea rsi, load_msg   # pointer to the message to be written
    mov rdx, 14         # message length
    syscall

    # Read
    mov rax, 0          # syscall number for sys_read
    mov rdi, 0          # file descriptor 0 (stdin)
    lea rsi, read_msg   # pointer to the buffer to store user input
    mov rdx, 255        # maximum number of bytes to read
    syscall

    # Write
    mov rax, 1          # syscall number for sys_write
    mov rdi, 1          # file descriptor 1 (stdout)
    mov rdx, rax 
    syscall             # writing the user input to the standard output

    # Exit
    mov rax, 60         # syscall number for sys_exit
    mov rdi, 0          # exit code 0
    syscall

load_msg:
    .asciz "Hello, World!\n"

read_msg:
    .space 256