memory.h

有助于了解操作系统如何启动之过程

/* memory.h - describe the memory map */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2002,2007,2008  Free Software Foundation, Inc.
 *
 *  GRUB 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.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef GRUB_MEMORY_MACHINE_HEADER
#define GRUB_MEMORY_MACHINE_HEADER	1

#include <grub/symbol.h>
#include <grub/machine/machine.h>
#ifndef ASM_FILE
#include <grub/types.h>
#endif

/* The scratch buffer used in real mode code.  */
#define GRUB_MEMORY_MACHINE_SCRATCH_ADDR	0x68000
#define GRUB_MEMORY_MACHINE_SCRATCH_SEG	(GRUB_MEMORY_MACHINE_SCRATCH_ADDR >> 4)
#define GRUB_MEMORY_MACHINE_SCRATCH_SIZE	0x10000

/* The real mode stack.  */
#define GRUB_MEMORY_MACHINE_REAL_STACK	(0x2000 - 0x10)

/* The size of the protect mode stack.  */
#define GRUB_MEMORY_MACHINE_PROT_STACK_SIZE	0x8000

/* The upper memory area (starting at 640 kiB).  */
#define GRUB_MEMORY_MACHINE_UPPER		0xa0000

/* The protected mode stack.  */
#define GRUB_MEMORY_MACHINE_PROT_STACK	\
	(GRUB_MEMORY_MACHINE_SCRATCH_ADDR + GRUB_MEMORY_MACHINE_SCRATCH_SIZE \
	 + GRUB_MEMORY_MACHINE_PROT_STACK_SIZE - 0x10)

/* The memory area where GRUB uses its own purpose. This part is not added
   into free memory for dynamic allocations.  */
#define GRUB_MEMORY_MACHINE_RESERVED_START	\
	GRUB_MEMORY_MACHINE_SCRATCH_ADDR
#define GRUB_MEMORY_MACHINE_RESERVED_END	\
	(GRUB_MEMORY_MACHINE_PROT_STACK + 0x10)

/* The area where GRUB is decompressed at early startup.  */
#define GRUB_MEMORY_MACHINE_DECOMPRESSION_ADDR	0x100000

/* The address of a partition table passed to another boot loader.  */
#define GRUB_MEMORY_MACHINE_PART_TABLE_ADDR	0x7be

/* The address where another boot loader is loaded.  */
#define GRUB_MEMORY_MACHINE_BOOT_LOADER_ADDR	0x7c00

/* The flag for protected mode.  */
#define GRUB_MEMORY_MACHINE_CR0_PE_ON		0x1

/* The code segment of the protected mode.  */
#define GRUB_MEMORY_MACHINE_PROT_MODE_CSEG	0x8

/* The data segment of the protected mode.  */
#define GRUB_MEMORY_MACHINE_PROT_MODE_DSEG	0x10

/* The code segment of the pseudo real mode.  */
#define GRUB_MEMORY_MACHINE_PSEUDO_REAL_CSEG	0x18

/* The data segment of the pseudo real mode.  */
#define GRUB_MEMORY_MACHINE_PSEUDO_REAL_DSEG	0x20

#ifndef GRUB_MACHINE_IEEE1275
#ifndef ASM_FILE
extern grub_size_t EXPORT_VAR(grub_lower_mem);
extern grub_size_t EXPORT_VAR(grub_upper_mem);
#endif
#endif

#endif /* ! GRUB_MEMORY_MACHINE_HEADER */