Adds reads()

src/console.asm

@@ -10,6 +10,7 @@ section .rodata
 section .bss
 	printfBuff	resb	printfBuffLen
 	printfArgs	resq	5 ;5=>rsi,rdx,rcx,r8,r9
+	readsCBuff	resb	1
 section .text
 	global	__INTERNAL_fmt
 
@@ -17,6 +18,7 @@ section .text
 	global	puts
 	global	printf
 	global	eprintf
+	global	reads
 
 ;----- print(*str[]) -----;
 ; Prints given string to the console to stdout
@@ -493,3 +495,51 @@ __INTERNAL_fmt:
 	pop	r12
 	leave
 	ret
+
+;----- reads(*inputBuffer[], len) -----;
+; Reads from console (stdin), stores input to inputBuffer[]
+; ~~Return value: Amount of written characters (+EOS) to inputBuffer[] (so RAX-1 => amount of read characters)~~
+; Return value: Amount of read characters
+; Used registers:
+;	rax*	(ret)
+;	rdi*	(arg) Pointer to inputBuffer[]
+;	rsi*	(arg) Size of inputBuffer[] (or less to read less characters)
+;	rdx*	arg for syscall
+;	r12	Stores inputBuffer[]
+;	r13	Stores len
+;	r14	Counts amount of read characters
+reads:
+	push	r12
+	push	r13
+	push	r14
+
+	lea	r12, [rdi]
+	mov	r13, rsi
+	dec	r13 ;account for EOS
+	xor	r14, r14
+
+	.readLoop:
+		mov	rax, NR_read
+		mov	rdi, FD_stdin
+		lea	rsi, [rel readsCBuff]
+		mov	rdx, 1
+		syscall
+
+		mov	al, [readsCBuff]
+		cmp	al, NL
+		je	.finish
+		cmp	r14, r13
+		jae	.readLoop ;Keep reading from stdin until \n is found as to flush stdin (too bad sys_lseek is not allowed on stdin, returns ESPIPE;illegal seek)
+		mov	byte [r12], al
+		inc	r12
+		inc	r14
+		jmp	.readLoop
+
+	.finish:
+	mov	byte [r12], EOS
+	mov	rax, r14
+
+	pop	r14
+	pop	r13
+	pop	r12
+	ret