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64 lines
1.7 KiB
ArmAsm
64 lines
1.7 KiB
ArmAsm
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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x86/gdt.s
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Handles initialization of the 32-bit global descriptor table.
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*******************************************************************************/
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.section .text
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.global gdt_flush
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.type gdt_flush, @function
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gdt_flush:
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# Load the new GDT pointer
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mov 4(%esp), %eax
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lgdtl (%eax)
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# 0x10 is the offset in the GDT to our data segment
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mov $0x10, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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# Far jump to our new code segment!
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movl $GDT_FLUSH_POSTJMP, %eax
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ljmp *(%eax)
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gdt_flush_postjmp:
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ret
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.global tss_flush
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.type tss_flush, @function
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tss_flush:
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# Load the index of our TSS structure - The index is 0x28, as it is the 5th
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# selector and each is 8 bytes long, but we set the bottom two bits (making
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# 0x2B) so that it has an RPL of 3, not zero.
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mov $0x2B, %ax
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# Load the task state register.
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ltr %ax
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ret
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.section .data
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GDT_FLUSH_POSTJMP:
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.long gdt_flush_postjmp
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.word 0x08 # 0x08 is the offset to our code segment
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