All functions work now. Readline supports backspace properly. Etc

kernel.asm

@@ -1,30 +1,86 @@
+[BITS 16]
   mov ax, 2000h
   mov ds, ax
 
   push msg
   call print
 
-  push msg2
+cmd_loop:
+  push cmd_prompt
   call print
 
-  push 13
-  push msg
-  push msg
+  push user_cmd
+  push 64
+  call readline
+
+  push newline
+  call print
+
+  push user_cmd
+  push cmd_help_text
+  push 4
   call strcmp
 
   cmp ax, 1
-  jne _ne
-  push msg_same
-  call print
-_ne:
+  je cmd_help
 
-  jmp $
+  push user_cmd
+  push cmd_clear_text
+  push 5
+  call strcmp
+
+  cmp ax, 1
+  je cmd_clear
+
+  push cmd_err
+  call print
+
+  jmp cmd_loop
+
+cmd_help:
+  push cmd_help_msg
+  call print
+  jmp cmd_loop
+
+cmd_help_msg:
+  db "XnoeOS Help Dialogue", 13, 10
+  db "--------------------", 13, 10
+  db "Commands: ", 13, 10
+  db " - help", 13, 10
+  db " : Displays this message", 13, 10
+  db " - clear", 13, 10
+  db " : Clears the screen", 13, 10
+  db 0
+
+cmd_clear:
+  mov ah, 02h
+  mov dh, 0
+  mov dl, 0
+  int 10h
+
+  mov ah, 0ah
+  mov cx, 2000
+  mov al, 20h
+  int 10h
+
+  jmp cmd_loop
 
 data:
   msg db "Kernel OK!", 13, 10, 0
-  msg2 db "Hello, World!", 13, 10, 0
-  msg_same db "They are the same", 13, 10, 0
+  cmd_prompt db ">>> ", 0
+  cmd_err db "Bad Command!", 13, 10, 13, 10, 0
+  
+  cmd_help_text db "help"
+  cmd_clear_text db "clear"
 
+  newline db 13, 10, 0
+
+
+
+user_cmd:
+  times 64 db 0 
+
+; print(str)
 print:
   push bp
   mov bp, sp
@@ -42,29 +98,85 @@ print_exit:
   pop bp
   ret
 
+; strcmp(length, str1, str2)
 strcmp:
   push bp
   mov bp, sp
-  mov ax, [bp + 4]
-  lea si, [bp+6]
-  lea di, [bp+8]
-  dec di
+  mov si, [bp + 6]
+  mov di, [bp + 8]
   mov word [bp - 2], 0
 strcmp_loop:
-  inc di
-  inc word [bp - 2]
+  mov ax, [bp + 4]
+  cmp [bp - 2], ax
+  je strcmp_equal
+
   lodsb
+
   cmp [di], al
   jne strcmp_notequal
-  cmp [bp - 2], ax
-  jne strcmp_equal
 
+  inc di
+  inc word [bp - 2]
+  jmp strcmp_loop
 
 strcmp_equal:
   mov ax, 1
-  pop bp
-  ret
+  jmp strcmp_exit
 strcmp_notequal:
   mov ax, 0
+strcmp_exit:
+  pop bp
+  ret
+
+; readline(max length, buffer)
+readline:
+  push bp
+  mov bp, sp
+  mov di, [bp + 6]
+  mov bx, 0
+readline_loop:
+  mov ah, 0h
+  int 16h
+
+  cmp ah, 01ch
+  je readline_exit
+
+  cmp ah, 0eh
+  je readline_backspace
+
+  mov byte [di], al
+  inc di
+  inc bx
+
+  mov ah, 0eh
+  mov cx, 1
+  int 10h
+
+  mov ax, [bp + 4]
+  cmp bx, ax
+  je readline_exit
+
+  jmp readline_loop
+
+readline_backspace:
+
+  cmp bx, 0
+  je readline_loop
+
+  dec di
+  dec bx
+
+  mov ah, 0eh
+  mov cx, 1
+  int 10h
+
+  mov ah, 0ah
+  mov cx, 1
+  mov al, 20h
+  int 10h
+
+  jmp readline_loop
+
+readline_exit:
   pop bp
   ret