读书笔记《30天自制操作系统》day02

http://blog.csdn.net/ltbylc/article/details/8280488

1. 将第一天直接生成软盘映像的代码抽取出引导扇区部分，ipl.asm

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1.         ORG     0x7c00            
2.   
3.         JMP     entry  
4.         DB      0x90  
5.         DB      "HELLOIPL"        
6.         DW      512               
7.         DB      1                 
8.         DW      1                 
9.         DB      2                 
10.         DW      224               
11.         DW      2880              
12.         DB      0xf0              
13.         DW      9             
14.         DW      18                
15.         DW      2                 
16.         DD      0                 
17.         DD      2880              
18.         DB      0,0,0x29          
19.         DD      0xffffffff        
20.         DB      "HELLO-OS   "     
21.         DB      "FAT12   "        
22.         RESB    18              ?  
23.   
24.   
25. entry:  
26.         MOV     AX,0              
27.         MOV     SS,AX  
28.         MOV     SP,0x7c00  
29.         MOV     DS,AX  
30.         MOV     ES,AX  
31.   
32.         MOV     SI,msg  
33. putloop:  
34.         MOV     AL,[SI]  
35.         ADD     SI,1              
36.         CMP     AL,0  
37.         JE      fin  
38.         MOV     AH,0x0e           
39.         MOV     BX,15             
40.         INT     0x10              
41.         JMP     putloop  
42. fin:  
43.         HLT                       
44.         JMP     fin               
45.   
46. msg:  
47.         DB      0x0a, 0x0a        
48.         DB      "hello, world"  
49.         DB      0x0a              
50.         DB      0  
51.   
52.         ;RESB   0x7dfe-$          
53.         ;times 0x7dfe-($-$$) db 0  
54.                 times 510-($-$$) db 0  
55.                 DB              0x55,0xaa  

2. 将引导扇区部分并入软盘映像文件中 helloos3.asm

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1. incbin "ipl.bin"  
2. times 1474560 - ($ - $$) db 0  

3. 生成的img文件可以被WinImage软件以软盘方式打开了