Я хочу читать и отображать содержимое текстового файла с помощью системных вызовов nasm и Linux. Мой текстовый файл называется «new.txt». Я написал следующий код и не получаю никакого вывода на терминале.Как читать и отображать содержимое текстового файла в nasm?
section .data
line db "This is George,",
db " and his first line.", 0xa, 0
len equ $ - line
line2 db "This is line number 2.", 0xa, 0
len2 equ $ - line2
filename: db 'ThisIsATestFile.txt', 0
section .bss
bssbuf: resb len ;any int will do here, even 0,
file: resb 4 ;since pointer is allocated anyway
global _start
section .text
_start:
; open file in read-only mode
mov eax, 5 ;sys_open file with fd in ebx
mov ebx, filename ;file to be opened
mov ecx, 0 ;O_RDONLY
int 80h
cmp eax, 0 ;check if fd in eax > 0 (ok)
jbe error ;can not open file
mov ebx, eax ;store new (!) fd of the same file
; read from file into bss data buffer
mov eax, 3 ;sys_read
mov ecx, bssbuf ;pointer to destination buffer
mov edx, len ;length of data to be read
int 80h
js error ;file is open but cannot be read
cmp eax, len ;check number of bytes read
jb close ;must close file first
; write bss data buffer to stderr
mov eax, 4 ;sys_write
push ebx ;save fd on stack for sys_close
mov ebx, 2 ;fd of stderr which is unbuffered
mov ecx, bssbuf ;pointer to buffer with data
mov edx, len ;length of data to be written
int 80h
pop ebx ;restore fd in ebx from stack
close:
mov eax, 6 ;sys_close file
int 80h
mov eax, 1 ;sys_exit
mov ebx, 0 ;ok
int 80h
error:
mov ebx, eax ;exit code
mov eax, 1 ;sys_exit
int 80h