Linux x86-64 Assembly Language termios Sample Code

test.asm

%define STDIN_FILENO 0
%define TCSAFLUSH 2
%define VMIN 6
%define VTIME 5
%define BRKINT 0x2
%define ICRNL 0x100
%define INPCK 0x10
%define ISTRIP 0x20
%define IXON 0x400
%define OPOST 0x1
%define CS8 0x30
%define ECHO 0x8
%define ICANON 0x2
%define IEXTEN 0x8000
%define ISIG 0x1

%macro get_termios 1
	mov		rdi, STDIN_FILENO
	mov		rsi, %1
	call		tcgetattr
	mov		rdi, err_tcgetattr
	cmp		rax, -1
	je		die
%endmacro

%macro set_termios 1
	mov		rdi, STDIN_FILENO
	mov		rsi, TCSAFLUSH
	mov		rdx, %1
	call		tcsetattr
	mov		rdi, err_tcsetattr
	cmp		rax, -1
	je		die
%endmacro

%macro print 1
	mov		rdi, %1
	xor		rax, rax
	call		printf
%endmacro

	global		main
	extern		printf, perror, tcsetattr, tcgetattr, read, iscntrl

	section		.data

err_read:
	db		"read", 0
err_tcsetattr:
	db		"tcsetattr", 0
err_tcgetattr:
	db		"tcgetattr", 0
output1:
	db		"%d", 0xd, 0xa, 0
output2:
	db		"%d ('%c')", 0xd, 0xa, 0
ctrl_check:
	dd		0x1f
intro:
	db		"Type from your keyboard. Press CTRL + q to exit.", 0xd, 0xa, 0

struc TERMIOS
	c_iflag: resd 1
	c_oflag: resd 1
	c_cflag: resd 1
	c_lflag: resd 1
	c_cc: resb 255
endstruc

orig_termios: istruc TERMIOS
	at c_iflag, dd 0
	at c_oflag, dd 0
	at c_cflag, dd 0
	at c_lflag, dd 0
	at c_cc, db ""
iend

raw_termios: istruc TERMIOS
	at c_iflag, dd 0
	at c_oflag, dd 0
	at c_cflag, dd 0
	at c_lflag, dd 0
	at c_cc, db ""
iend

char_quit:
	dd		'q'

	section		.bss
input_char:
	resb		1

	section		.txt

main:
	print		intro
	get_termios	orig_termios
	get_termios	raw_termios

	;enable raw mode
	;set c_iflag
	mov		r15, BRKINT
	or		r15, ICRNL
	or		r15, INPCK
	or		r15, ISTRIP
	or		r15, IXON
	not		r15
	mov		r14, [raw_termios + c_iflag]
	and		r14, r15
	mov		[raw_termios + c_iflag], r14

	;set c_oflag
	mov		r15, OPOST
	not		r15
	mov		r14, [raw_termios + c_oflag]
	and		r14, r15
	mov		[raw_termios + c_oflag], r14

	;set c_cflag
	mov		r15, CS8
	mov             r14, [raw_termios + c_cflag]
	or		r14, r15
	mov		[raw_termios + c_cflag], r14

	;set c_lflag
	mov		r15, ECHO
	or		r15, ICANON
	or		r15, IEXTEN
	or		r15, ISIG
	not		r15
	mov		r14, [raw_termios + c_lflag]
	and		r14, r15
	mov		[raw_termios + c_lflag], r14

	;set VMIN and VTIME
	mov		r15, raw_termios + c_cc
	mov		byte [r15 + VMIN], 0
	mov		byte [r15 + VTIME], 1
	mov		[raw_termios + c_cc], r15

	set_termios	raw_termios
	;end of enable raw mode

main_loop:
	mov		[input_char], byte 0
	mov		rdi, STDIN_FILENO
	mov		rsi, input_char
	mov		rdx, 1
	call		read
	mov		rdi, err_read
	cmp		rax, -1
	je		die


	mov		rdi, [input_char]
	call		iscntrl
	cmp		rax, 0
	je		isnotctrl

	cmp		byte [input_char], 0
	je		ender

	mov		rsi, [input_char]
	print		output1

ender:
	mov		r11, [ctrl_check]
	and		r11, [char_quit]
	cmp		r11, [input_char]
	je		break

	jmp		main_loop

isnotctrl:
	mov		rdx, [input_char]
	mov		rsi, [input_char]
	print		output2

	jmp		ender	

break:
	set_termios	orig_termios
	mov		rdi, 0
	jmp		exit

die:
	call		perror
	mov		rdi, 1
	call		exit	

exit:
	mov		rax, 0x3c
	syscall
	ret