Trying to set up a stack.

source/boot.asm

@@ -37,7 +37,7 @@ mov cl, 0x2
 ;Set the destination
 mov ax, 0x1000
 mov es, ax
-mov bx, 0
+mov bx, 0x200
 ;Set the size
 mov al, 0x20
 ;Load
@@ -45,7 +45,7 @@ mov ah, 0x2
 int 0x13
 
 ;Boot the system
-jmp 0x1000:0
+jmp 0x1000:0x200
 
 ;Padding
 times 0x1fe-($-$$) db 0

source/readln.inc

@@ -25,10 +25,6 @@ mov byte [.lastln], dh
 mov ah, 0x0
 int 0x16
 
-;Check for null
-cmp al, 0x0
-je .loop
-
 ;Check for return
 cmp al, 0xd
 je .return
@@ -84,7 +80,7 @@ jmp .char
 ;Get the cursor position
 mov ah, 0x3
 int 0x10
-;More from the end of a line to the beginning of the next one
+;Move from the end of a line to the beginning of the next one
 cmp dl, [cpl]
 je .nextln
 ;Move forward within a line
@@ -107,12 +103,12 @@ jmp .checkln
 
 .backspace:
 ;Check for the input beginning
-cmp bl, 0x0
+cmp bl, 0x1
 je .loop
 ;Get the cursor position
 mov ah, 0x3
 int 0x10
-;More from the beginning of a line to the end of the previous one
+;Move from the beginning of a line to the end of the previous one
 cmp dl, 0x1
 je .prevln
 ;Move backward within a line

source/system.asm

@@ -1,3 +1,4 @@
+[ORG 0x200]
 jmp start
 
 ;Calls
@@ -20,6 +21,13 @@ start:
 mov ax, 0x1000
 mov ds, ax
 
+;Set up the stack
+cli
+mov ax, 0x1000
+mov ss, ax
+mov sp, 0x200
+sti
+
 ;Get the terminal width
 mov ah, 0xf
 int 0x10