os-k/kaleid/kernel/mm/gdt.c

60 lines
2.6 KiB
C

//----------------------------------------------------------------------------//
// GNU GPL OS/K //
// //
// Desc: Mapping and checking memory related functions //
// //
// //
// 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 //
// 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/>. //
//----------------------------------------------------------------------------//
#include <kernel/mm.h>
// The Gdt
GdtEntry_t gdtEntries[5];
GdtPtr_t gdtPtr;
static void SetGdtEntry(int index, uint base, uint limit, uchar access,
uchar granularity)
{
gdtEntries[index].lowBase = (base & 0xFFFF);
gdtEntries[index].middleBase = (base >> 16) & 0xFF;
gdtEntries[index].highBase = (base >> 24) & 0xFF;
gdtEntries[index].lowLimit = (limit & 0xFFFF);
gdtEntries[index].granularity = (limit >> 16) & 0x0F;
gdtEntries[index].granularity |= granularity & 0xF0;
gdtEntries[index].access = access;
}
void MmInitGdt(void)
{
gdtPtr.limit = (sizeof(GdtEntry_t) * 5) - 1;
gdtPtr.base = (uint)(ullong)&gdtEntries;
SetGdtEntry(0,0,0,0,0);
/* XXX set TSS register */
//MmLoadGdt(&gdtPtr);
}