Added handling for skipping non-renderable characters

Added handling for backspace character

console.asm

@@ -16,16 +16,30 @@ pub read_line:
 		je read_line_keyloop ; If the current key is same as previous, we loop
 		mov r4, r1 ; Storing current key as previous
 		
-		cmp r1, 0x100
+		cmp r1, 0x100 ; Is the key down or up?
 		jbe read_line_keyloop ; If the key was up, we loop
 		xor r1, r1, 0x100 ; We remove the "down" bit
 		
 		cmp r1, 10 ; Was the key Enter?
 		je read_line_finished ; If so, we're finished
-		
-		store_8 [r3], r1 ; Else, we store the key in the buffer
-		add r3, r3, 1 ; We advance forward
-		jmp read_line_keyloop
+
+		cmp r1, 32 ; Was the key under Space? i.e. non-renderable
+		jb read_line_keyloop ; If so, we loop
+
+		cmp r1, 127 ; Was the key Backspace?
+		je read_line_backspace ; If yes we need to move one character back
+
+		read_line_store:
+			store_8 [r3], r1 ; Else, we store the key in the buffer
+			add r3, r3, 1 ; We advance forward
+			jmp read_line_keyloop
+
+		read_line_backspace:
+			cmp r3, r2
+			je read_line_keyloop ; If we are at the start, we loop
+			sub r3, r3, 1 ; We move back one character
+			jmp read_line_keyloop
+
 	read_line_finished:
 		store_8 [r3], zr ; We store null at the end so the string is finished
 		mov r1, r2 ; Recovering the buffer pointer