mirror of
https://github.com/reactos/reactos.git
synced 2024-06-25 15:31:47 +00:00
eeff926ede
- Move DiskStopFloppyMotor() calls into the implementations of Boot(New)LinuxKernel() and Reboot() HW functions, and the explanation comments in ChainLoadBiosBootSectorCode(). - Remove unneeded DiskStopFloppyMotor() dummies in ARM and PPC code. - Use more adequate bitmask value to be sent to floppy's Digital Output Register for shutting down its motor (based on OSDev & our floppy controller driver).
288 lines
6.2 KiB
ArmAsm
288 lines
6.2 KiB
ArmAsm
/*
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* FreeLoader
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* Copyright (C) 1998-2002 Brian Palmer <brianp@sginet.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <asm.inc>
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#include <arch/pc/x86common.h>
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#include <arch/pc/pcbios.h>
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EXTERN _BootMain:PROC
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EXTERN _InitIdt:PROC
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EXTERN _i386Idt:DWORD
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//EXTERN _i386idtptr:FWORD
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EXTERN cmdline:DWORD
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EXTERN _DiskStopFloppyMotor:PROC
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#ifdef _USE_ML
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EXTERN __bss_start__:DWORD
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EXTERN __bss_end__:DWORD
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#endif
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.code32
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PUBLIC _RealEntryPoint
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_RealEntryPoint:
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/* Setup segment selectors */
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mov ax, PMODE_DS
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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mov ss, ax
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/* Setup protected mode stack */
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mov esp, dword ptr ds:[stack32]
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/* Load the IDT */
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#ifdef _USE_ML
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lidt fword ptr ds:[i386idtptr]
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#else
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lidt i386idtptr
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#endif
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/* Continue execution */
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jmp dword ptr ds:[ContinueAddress]
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PUBLIC ContinueAddress
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ContinueAddress:
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.long _FrldrStartup
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_FrldrStartup:
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/* Store BootDrive and BootPartition */
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mov byte ptr ds:[_FrldrBootDrive], dl
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xor eax, eax
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mov al, dh
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mov dword ptr ds:[_FrldrBootPartition], eax
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/* Patch long jump with real mode entry point */
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mov eax, dword ptr ds:[BSS_RealModeEntry]
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mov dword ptr ds:[SwitchToReal16Address], eax
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/* Clean out BSS */
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xor eax, eax
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mov edi, offset __bss_start__
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mov ecx, offset __bss_end__ + 3
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sub ecx, edi
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shr ecx, 2
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rep stosd
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/* Initialize the idt */
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call _InitIdt
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/* Pass the command line to BootMain */
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mov eax, offset cmdline
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/* GO! */
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push eax
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call _BootMain
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/* We should never get here */
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stop:
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jmp short stop
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nop
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nop
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PUBLIC _Reboot
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_Reboot:
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/* Stop the floppy drive motor */
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call _DiskStopFloppyMotor
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/* Set the function ID */
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mov bx, FNID_Reboot
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/* Switch to real mode (we don't return) */
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jmp SwitchToReal
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/*
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* VOID __cdecl ChainLoadBiosBootSectorCode(
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* IN UCHAR BootDrive OPTIONAL,
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* IN ULONG BootPartition OPTIONAL);
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*
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* RETURNS: Nothing
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*/
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PUBLIC _ChainLoadBiosBootSectorCode
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_ChainLoadBiosBootSectorCode:
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/* Set the boot drive */
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mov dl, [esp + 4]
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test dl, dl
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jnz set_part
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mov dl, byte ptr ds:[_FrldrBootDrive]
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/* Set the boot partition */
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set_part:
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mov eax, [esp + 8]
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test eax, eax
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jnz continue
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mov eax, dword ptr ds:[_FrldrBootPartition]
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continue:
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/* Store the 1-byte truncated partition number in DH */
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mov dh, al
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/*
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* Don't stop the floppy drive motor when we are just booting a bootsector,
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* a drive, or a partition. If we were to stop the floppy motor, the BIOS
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* wouldn't be informed and if the next read is to a floppy then the BIOS
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* will still think the motor is on and this will result in a read error.
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*/
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// call _DiskStopFloppyMotor
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/* Set the function ID */
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mov bx, FNID_ChainLoadBiosBootSectorCode
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/* Switch to real mode (we don't return) */
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jmp SwitchToReal
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/*
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* U16 PxeCallApi(U16 Segment, U16 Offset, U16 Service, VOID *Parameter);
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*
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* RETURNS:
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*/
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PUBLIC _PxeCallApi
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_PxeCallApi:
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/* copy entry point */
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mov eax, [esp + 4]
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shl eax, 16
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mov ax, [esp + 8]
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mov dword ptr ds:[BSS_PxeEntryPoint], eax
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/* copy function */
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mov ax, [esp + 12]
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mov word ptr ds:[BSS_PxeFunction], ax
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/* convert pointer to data buffer to segment/offset */
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mov eax, [esp + 16]
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shr eax, 4
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and eax, HEX(0f000)
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mov word ptr ds:[BSS_PxeBufferSegment], ax
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mov eax, [esp + 16]
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and eax, HEX(0ffff)
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mov word ptr ds:[BSS_PxeBufferOffset], ax
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pusha
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/* Set the function ID and call realmode */
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mov bx, FNID_PxeCallApi
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call i386CallRealMode
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popa
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mov ax, word ptr [BSS_PxeResult]
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ret
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PUBLIC i386CallRealMode
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i386CallRealMode:
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/* Set continue address and switch to real mode */
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mov dword ptr ds:[ContinueAddress], offset i386CallRealMode_return
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jmp SwitchToReal
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i386CallRealMode_return:
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ret
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/* Entrypoint for realmode function calls
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* ContinueAddress must be set to the return point from realmode
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* bx must be set to the ID of the realmode function to call. */
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PUBLIC SwitchToReal
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SwitchToReal:
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/* Set sane segments */
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mov ax, PMODE_DS
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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mov ss, ax
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/* Save 32-bit stack pointer */
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mov dword ptr ds:[stack32], esp
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/* jmp to 16-bit segment to set the limit correctly */
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.byte HEX(0ea) // jmp far RMODE_CS:switch_to_real16
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SwitchToReal16Address:
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.long 0 // receives address of switch_to_real16
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.word RMODE_CS
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nop
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/* 16-bit stack pointer */
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stack16:
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.word STACK16ADDR
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/* 32-bit stack pointer */
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stack32:
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.long STACKADDR
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.align 4 /* force 4-byte alignment */
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gdt:
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/* NULL Descriptor */
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.word HEX(0000)
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.word HEX(0000)
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.word HEX(0000)
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.word HEX(0000)
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/* 32-bit flat CS */
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.word HEX(FFFF)
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.word HEX(0000)
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.word HEX(9A00)
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.word HEX(00CF)
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/* 32-bit flat DS */
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.word HEX(FFFF)
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.word HEX(0000)
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.word HEX(9200)
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.word HEX(00CF)
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/* 16-bit real mode CS */
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.word HEX(FFFF)
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.word HEX(0000)
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.word HEX(9E00)
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.word HEX(0000)
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/* 16-bit real mode DS */
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.word HEX(FFFF)
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.word HEX(0000)
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.word HEX(9200)
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.word HEX(0000)
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/* GDT table pointer */
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gdtptr:
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.word HEX(27) /* Limit */
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.long gdt /* Base Address */
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// See _i386IdtDescriptor
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PUBLIC i386idtptr
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i386idtptr:
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.word 255 /* Limit */
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.long _i386Idt /* Base Address */
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PUBLIC _FrldrBootDrive
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_FrldrBootDrive:
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.byte 0
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PUBLIC _FrldrBootPartition
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_FrldrBootPartition:
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.long 0
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END
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