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/* Copyright (C) 2004 The SOS Team
This program 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 2
of the License, or (at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
#ifndef _SOS_HWSEGS_H_
#define _SOS_HWSEGS_H_
/**
* @file segments.h
*
* Global and local (GDT/LDT) segment descriptor definition and
* structure. These segments map virtual addresses (ie
* data/instruction addresses, relative to these segment descriptors)
* to linear addresses (ie addresses in the paged-memory space).
*
* @see Intel x86 doc, vol 3 chapter 3.
*/
/*
* Global segment selectors (GDT) for SOS/x86.
*
* @see gdt.h
*/
#define SOS_SEG_NULL 0 /* NULL segment, unused by the procesor */
#define SOS_SEG_KCODE 1 /* Kernel code segment */
#define SOS_SEG_KDATA 2 /* Kernel data segment */
#ifndef ASM_SOURCE
/**
* Helper macro that builds a segment register's value
*/
#define SOS_BUILD_SEGMENT_REG_VALUE(desc_privilege,in_ldt,seg_index) \
( (((desc_privilege) & 0x3) << 0) \
| (((in_ldt)?1:0) << 2) \
| ((seg_index) << 3) )
#else
/*
* Assembler-compliant version.
*
* Caution: In assembler code, "in_ldt" MUST be either 1 or 0, nothing
* else.
*/
#define SOS_BUILD_SEGMENT_REG_VALUE(desc_privilege,in_ldt,seg_index) \
( (((desc_privilege) & 0x3) << 0) \
| ((in_ldt & 1) << 2) \
| ((seg_index) << 3) )
#endif
/*
* Local segment selectors (LDT) for SOS/x86
*/
/* None */
#endif /* _SOS_HWSEGS_H_ */
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