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发信人: mephisto (梦菲斯特*大宝宝), 信区: Linux
标  题: Re: 源码分析的问题
发信站: BBS 水木清华站 (Tue Dec 12 18:02:12 2000)

这个地方不是setup.S写的,
是bootloader 写的. 例如lilo和 loadlin, 用来放启动的linux的信息的.
看 arch/i386/boot/bootsect.S bsetup.s
! bootsect.s is loaded at 0x7c00 by the bios-startup routines, and moves
! itself out of the way to address 0x90000, and jumps there.
!
! bde - should not jump blindly, there may be systems with only 512K low
! memory.  Use int 0x12 to get the top of memory, etc.
!
! It then loads 'setup' directly after itself (0x90200), and the system
! at 0x10000, using BIOS interrupts.
!
--------------------

! Signature words to ensure LILO loaded us right
                            ^^^^^

INITSEG  = 0x9000       ! 0x9000, we move boot here - out of the way
SYSSEG   = 0x1000       ! 0x1000, system loaded at 0x10000 (65536).
SETUPSEG = 0x9020       ! 0x9020, this is the current segment
                        ! ... and the former contents of CS
DELTA_INITSEG = SETUPSEG - INITSEG ! 0x0020

【在 sonicbb (风间苍月) 的大作中提到: 】
∶ 小弟在分析linux内河源代码的Head.S时,遇到如下语句
∶         cmpw $(CL_MAGIC),CL_MAGIC_ADDR
∶ 前面有定义:CL_MAGIC=0xa33f      CL_MAGIC_ADDR=0x90020
∶ 请问setup.S在0x90020处写入了一个什么东东?我老是找不到setup.S中的相关部分.
∶ 谢谢!

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