【zz】linux启动过程（2）－setup.S分析

II、实模式下的初始化

实模式下的初始化,主要是指从内核引导成功后，到进入保护模式之前系统所做的一些处理。在内 核源码中对应的程序是 /Arch/i386/boot/setup.S；以下部分主要是针对此文件进行的分析。这部分的分析主要是要弄懂它的处理流程和 INITSEG(9000:0000)段参数表的建立，此参数表包含了很多硬件参数，这些都是以后进行保护模式下初始化，以及核心建立的基础。

1. 几个其它相关文件：

<1> /Arch/i386/boot/bootsect.S

<2> /include/linux/config.h

<3> /include/asm/boot.h

<4> /include/ asm/segment.h

<5> /include/linux/version.h

<6> /include/linux/compile.h

2. 实模式下的初始化过程分析：





INITSEG(9000:0000)段参数表：（参见Include/linux/tty.h）

参数名	偏移量(段址均为0x9000)	长度Byte	参考文件
PARAM_CURSOR_POS	0x0000	2	Arch/i386/boot/video.S
extended mem Size	0x0002	2	Arch/i386/boot/setup.S
PARAM_VIDEO_PAGE	0x0004	2	Arch/i386/boot/video.S
PARAM_VIDEO_MODE	0x0006	1	Arch/i386/boot/video.S
PARAM_VIDEO_COLS	0x0007	1	Arch/i386/boot/video.S
没用	0x0008	2	Include/linux/tty.h
PARAM_VIDEO_EGA_BX	0x000a	2	Arch/i386/boot/video.S
没用	0x000c	2	Include/linux/tty.h
PARAM_VIDEO_LINES	0x000e	1	Arch/i386/boot/video.S
PARAM_HAVE_VGA	0x000f	1	Arch/i386/boot/video.S
PARAM_FONT_POINTS	0x0010	2	Arch/i386/boot/video.S
PARAM_LFB_WIDTH	0x0012	2	Arch/i386/boot/video.S
PARAM_LFB_HEIGHT	0x0014	2	Arch/i386/boot/video.S
PARAM_LFB_DEPTH	0x0016	2	Arch/i386/boot/video.S
PARAM_LFB_BASE	0x0018	4	Arch/i386/boot/video.S
PARAM_LFB_SIZE	0x001c	4	Arch/i386/boot/video.S
暂未用①	0x0020	4	Include/linux/tty.h
PARAM_LFB_LINELENGTH	0x0024	2	Arch/i386/boot/video.S
PARAM_LFB_COLORS	0x0026	6	Arch/i386/boot/video.S
暂未用②	0x002c	2	Arch/i386/boot/video.S
PARAM_VESAPM_SEG	0x002e	2	Arch/i386/boot/video.S
PARAM_VESAPM_OFF	0x0030	2	Arch/i386/boot/video.S
PARAM_LFB_PAGES	0x0032	2	Arch/i386/boot/video.S
保留	0x0034--0x003f		Include/linux/tty.h
APM BIOS Version③	0x0040	2	Arch/i386/boot/setup.S
BIOS code segment	0x0042	2	Arch/i386/boot/setup.S
BIOS entry offset	0x0044	4	Arch/i386/boot/setup.S
BIOS 16 bit code seg	0x0048	2	Arch/i386/boot/setup.S
BIOS data segment	0x004a	2	Arch/i386/boot/setup.S
支持32位标志④	0x004c	2	Arch/i386/boot/setup.S
BIOS code seg length	0x004e	4	Arch/i386/boot/setup.S
BIOS data seg length	0x0052	2	Arch/i386/boot/setup.S
hd0 参数	0x0080	16	Arch/i386/boot/setup.S
hd0 参数	0x0090	16	Arch/i386/boot/setup.S
PS/2 device 标志⑤	0x01ff	1	Arch/i386/boot/setup.S

* 注 ： ① Include/linux/tty.h ： CL_MAGIC and CL_OFFSET here

1.  
   1. 
      
   2. Include/linux/tty.h ：

unsigned char rsvd_size; /* 0x2c */

unsigned char rsvd_pos; /* 0x2d */

③ 0表示没有APM BIOS

④ 0x0002置位表示支持32位模式

⑤ 0表示没有，0x0aa表示有鼠标器

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