os-k/boot/loader/io/lmmem.asm

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2019-01-16 11:04:44 +01:00
;=----------------------------------------------------------------------------=;
; GNU GPL OS/K ;
; ;
; Desc: Basic Memory Long mode Functions ;
; (x86_64 architecture only) ;
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; ;
; ;
; 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/>. ;
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;=----------------------------------------------------------------------------=;
[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