;=----------------------------------------------------------------------------=;
;                            GNU GPL OS/K                                      ;
;                                                                              ;
;   Desc:   Basic Memory Long mode Functions                                   ;
;                   (x86_64 architecture only)                                 ;
;                                                                              ;
;                                                                              ;
;   Copyright © 2018-2019 The OS/K Team                                        ;
;                                                                              ;
;   This file is part of OS/K.                                                 ;
;                                                                              ;
;   OS/K is free software: you can redistribute it and/or modify               ;
;   it under the terms of the GNU General Public License as published by       ;
;   the Free Software Foundation, either version 3 of the License, or          ;
;   (at your option) any later version.                                        ;
;                                                                              ;
;   OS/K is distributed in the hope that it will be useful,                    ;
;   but WITHOUT ANY WARRANTY; without even the implied warranty of             ;
;   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              ;
;   GNU General Public License for more details.                               ;
;                                                                              ;
;   You should have received a copy of the GNU General Public License          ;
;   along with OS/K.  If not, see <https://www.gnu.org/licenses/>.             ;
;=----------------------------------------------------------------------------=;
[BITS 64]

;; GLOBAL DATA
A20_OK          db  0

;; TEXT

check_a20:
    cmp BYTE [A20_OK], 1
    je .A20Success
    mov bl, 0x0C
    mov esi, Fail
    call write
    jmp Die
.A20Success:
    mov bl, 0x0A
    mov esi, Pass
    call write
    ret