CPU 8086
ORG 0x500

jmp start

;Calls
%include "CMPSTR.INC"
%include "PRINTSTR.INC"
%include "READSTR.INC"
%include "NEWLINE.INC"
%include "PRINTLN.INC"
%include "READLN.INC"

;Commands
%include "ECHO.INC"
%include "FILEIFY.INC"
%include "HELLO.INC"
%include "HELP.INC"
%include "KEYCODE.INC"

start:

;Set up the stack
cli
mov sp, stack
add sp, 0x100
sti

;Print a welcome message
mov si, welcomemsg
call println

loop:

;Prompt for and read a command
;Print a prompt
mov si, prompt
call printstr
;Read a command
mov di, buffer
mov al, 0xff
call readln

;Identify and execute the command
exec:
;Check for no command
cmp byte [buffer], 0x0
je loop
.echo:
;Check
mov si, buffer
mov di, cmd.echo
call cmpstr
jnc .fileify
;jnc .hello
;Execute
call echo
jmp loop
.fileify:
;Check
mov si, buffer
mov di, cmd.fileify
call cmpstr
jnc .hello
;Execute
call fileify
jmp loop
.hello:
;Check
mov si, buffer
mov di, cmd.hello
call cmpstr
jnc .help
;Execute
call hello
jmp loop
.help:
;Check
mov si, buffer
mov di, cmd.help
call cmpstr
jnc .keycode
;Execute
call help
jmp loop
.keycode:
;Check
mov si, buffer
mov di, cmd.keycode
call cmpstr
jnc .error
;Execute
call keycode
jmp loop
.error:
mov si, errormsg
call println
jmp loop

welcomemsg db 0xd, 0xa, "Welcome to EttinOS!", 0xd, 0xa, 0x0

prompt db "> ", 0x0

cmd:
.echo    db "echo", 0x0
.fileify  db "fileify", 0x0
.hello   db "hello", 0x0
.help    db "help", 0x0
.keycode db "keycode", 0x0

errormsg db "Unknown command", 0x0

buffer times 0xff db 0x0

stack: