;=----------------------------------------------------------------------------=;
;                            GNU GPL OS/K                                      ;
;                                                                              ;
;   Desc:   Memory Design Structures                                           ;
;                   (x86_64 architecture only)                                 ;
;                                                                              ;
;                                                                              ;
;   Copyright © 2018-2020 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 32]
extern kernelEnd
extern _bss
global newKernelEnd
global newStackEnd
global GDT64

[section .text]
KERNEL_STACK        equ 1 * 1024 * 1024          ; 1MB of stack
newKernelEnd        dq  0x0
newStackEnd         dq  0x0

[section .rodata]
;; GDT WITH DOC
ALIGN 4096
GDT64:
        ;; Null selector within 64 bits
        .null:
            dq  0x0         ; Zero entry
        ;; 64-bit code selector (ring 0)
        .code: equ $ - GDT64
            dq (1<<43) | (1<<44) | (1<<47) | (1<<53)
            ;     |         |         |         |
            ;     |         |         |         `------ 64-bit selector
            ;     |         |         `---------------- Present selector
            ;     |         `-------------------------- Descriptor type
            ;     `------------------------------------ Executable segment
        .pointer:
                        dw $ - GDT64 - 1
                        dq GDT64


;; EMPTY PAGE TABLES (identity of the first 4GiB)
[section .bss]
ALIGN 4096
PML4_table:
    resb 4096
PDP_table:
    resb 4096
PD_table:
    resb 4096