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sortix--sortix/sortix/x64/gdt.s
2011-10-10 01:16:36 +02:00

71 lines
1.7 KiB
ArmAsm

/******************************************************************************
COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
This file is part of Sortix.
Sortix 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.
Sortix 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 Sortix. If not, see <http://www.gnu.org/licenses/>.
x64/gdt.cpp
Handles initialization of the 64-bit global descriptor table.
******************************************************************************/
.section .text
.global gdt_flush
.type gdt_flush, @function
gdt_flush:
# Load the new GDT pointer
lgdtq (%rdi)
# 0x10 is the offset in the GDT to our data segment
mov $0x10, %ax
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
# 0x08 is the offset to our code segment: Far jump!
ljmp *GDT_FLUSH_POSTJMP
gdt_flush_postjmp:
ret
.global idt_flush
.type idt_flush, @function
idt_flush:
# Load the IDT pointer.
lidt (%rdi)
# Enable interrupts
sti
ret
.global tss_flush
.type tss_flush, @function
tss_flush:
# Load the index of our TSS structure - The index is 0x28, as it is the 5th
# selector and each is 8 bytes long, but we set the bottom two bits (making
# 0x2B) so that it has an RPL of 3, not zero.
mov $0x2B, %ax
# Load the task state register.
ltr %ax
ret
.section .data
GDT_FLUSH_POSTJMP:
.long gdt_flush_postjmp
.word 0x08