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- 保护模式下写变量有关问题
日期:2014-05-16 浏览次数:20686 次
保护模式下写变量问题
现在在学习写内核
一写变量就出现内核错误呀 怎么搞的?
我把内核放到了0x80000处
链接内核用的是ld
-N -s --oformat binary -e _start -Ttext 0x80000
我知道这也许是保护模式下定位变量的问题
但我用的是C语言怎么会这样?
kernel.asm
[section .text]
[bits 32]
global _start
extern init
_start:
mov ax,cs
mov ds,ax
mov es,ax
mov fs,ax
jmp init
init.c
void init()
{
qwe=1; <----------------运行到这里就出现堆栈错误
while(1)
;
}
堆栈没有问题 已经检查了
用bochs调试结果:
D:\Program Files\Bochs-2.3.pre3\tinix> D:\Progra~1\Bochs-2.3.pre3\bochsdbg.exe -q -f bochsrc.bxrc
00000000000i[APIC?] local apic in initializing
========================================================================
Bochs x86 Emulator 2.3.pre3
Build from CVS snapshot on August 6, 2006
========================================================================
00000000000i[ ] reading configuration from bochsrc.bxrc
00000000000i[ ] installing win32 module as the Bochs GUI
00000000000i[ ] using log file bochsout.txt
Next at t=0
(0) [0xfffffff0] f000:fff0 (unk. ctxt): jmp far f000:e05b ; ea5be000f0
<bochs:1> pb 0x80000
<bochs:2> c
(0) Breakpoint 1, 0x00080000 in ?? ()
Next at t=1796393
(0) [0x00080000] 0030:00080000 (unk. ctxt): mov ax, cs ; 668cc8
<bochs:3> s
Next at t=1796394
(0) [0x00080003] 0030:00080003 (unk. ctxt): mov ds, ax ; 8ed8
<bochs:4>
Next at t=1796395
(0) [0x00080005] 0030:00080005 (unk. ctxt): mov es, ax ; 8ec0
<bochs:5>
Next at t=1796396
(0) [0x00080007] 0030:00080007 (unk. ctxt): mov fs, ax ; 8ee0
<bochs:6>
Next at t=1796397
(0) [0x00080009] 0030:00080009 (unk. ctxt): jmp .+0x00000046 (0x00080054) ; e946000000
<bochs:7>
Next at t=1796398
(0) [0x00080054] 0030:00080054 (unk. ctxt): push ebp ; 55
<bochs:8>
Next at t=1796399
(0) [0x00080055] 0030:00080055 (unk. ctxt): mov ebp, esp ; 89e5
<bochs:9>
Next at t=1796400
(0) [0x00080057] 0030:00080057 (unk. ctxt): sub esp, 0x00000008 ; 83ec08
<bochs:10>
Next at t=1796401
(0) [0x0008005a] 0030:0008005a (unk. ctxt): mov dword ptr ds:0x80080, 0x0000004e ; c705800008004e000000
<bochs:11> print-stack
Stack address size 4
¦ STACK 0x000003f3 [0x00ff53f0]
¦ STACK 0x000003f7 [0x00ff53f0]
¦ STACK 0x000003fb [0x00ff53f0]
¦ STACK 0x000003ff [0x0003f8f0]
¦ STACK 0x00000403 [0x00000000]