Why does not console accept reverse line feed?-CodePudding

So, I want to create a game of life simulator on the console. For that, I need to move the cursor up so I can rewrite on it and I can do that with \u008d.

I try that on the console:

echo -e "Everyone\n\u008dHi"

This gives me the result:

Hieryone

This is the expected result, and proves that my console accepts that character. But, when I try the exact same thing in NASM,

  global _start

  segment .text

_start:
  ;; Print message
  mov   rax, 1
  mov   rdi, 1
  mov   rsi, message
  mov   rdx, length
  syscall

  ;; Exit
  mov   rax, 60
  mov   rdi, 0
  syscall

  segment .data
message: db "Everyone", 0xa, 0x8d, "Hi"
length:  equ $ - message

And run it like,

nasm example.asm -f elf64 -o output.o
ld output.o -o output
./output

I get,

Everyone
�Hi

Why is that? Is there something that changes the way this character is interpreted in my NASM program? Am I missing something in the Unicode? Or is there another alternative that would allow me to move the cursor back? Any help would be useful. (I am on Linux btw)

CodePudding user response：

I suggest you compare it with the hexdump.

$ echo -e "Everyone\n\u008dHi" | hexdump -C
00000000  45 76 65 72 79 6f 6e 65  0a c2 8d 48 69 0a        |Everyone...Hi.|
0000000e

$ ./output | hexdump -C
00000000  45 76 65 72 79 6f 6e 65  0a 8d 48 69              |Everyone..Hi|
0000000c

As you see, the difference is whether you have 0xc2 or not (except for newline 0x0a). In UTF-8, 0x8d must be represented as 0xc2 0x8d.

Therefore, the following modifications will give the expected results.

message: db "Everyone", 0xa, 0xc2, 0x8d, "Hi"