[高级]gcc 中 怎么得到 一个变量的 段地址和偏移地址？？

zjneter

gcc 中 怎么得到 一个变量的 段地址和偏移地址？？
tc中 FP_SEG 类似的？？ 有么 请高手指点
djgpp 中怎么搞 主要目的是使用int86x()
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下面的程序在xp下 编译成功 但是运行程序出错 为啥？
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#include<stdio.h>;
#include<dos.h>;

#define FP_OFF(fp)        ((unsigned)(fp))
#define FP_SEG(fp)        ((unsigned)((unsigned long)(fp) >;>; 16))

typedef unsigned int WORD;
typedef unsigned long DWORD;
typedef unsigned long long QWORD;
unsigned long CYLINDERS,HEADS,SECTOR_PER_TRACK;
unsigned long long SECTORS;
unsigned int BYTE_PER_SECTOR;

int get_parameter(int drive)
{
        union REGS regs;
        struct SREGS sregs;
        struct{
                WORD packetsize;
                WORD infoflags;
                DWORD cylns;
                DWORD heads;
                DWORD sects_per_track;
                QWORD sectors;
                WORD bps;
        }package;
        regs.h.ah=0x48;
        regs.h.dl=0x80;
        sregs.ds=FP_SEG(&package);
        regs.x.si=FP_OFF(&package);
        int86x(0x13,&regs,&regs,&sregs);
        CYLINDERS=package.cylns;
        HEADS=package.heads;
        SECTOR_PER_TRACK=package.sects_per_track;
        SECTORS=package.sectors;
        BYTE_PER_SECTOR=package.bps;
        if (regs.h.ah)
                return regs.h.ah;
        else
                return 0;
}

int main()
{
        if (get_parameter(0x80)==0)
        {
                printf("%ldCYLINDERS:\n",CYLINDERS);
                printf("%ldHEADS:\n",HEADS);
                printf("%ldSECTOR_PER_TRACK:\n",SECTOR_PER_TRACK);
                printf("%lldSECTORS:\n",SECTORS);
                printf("%dBYTE_PER_SECTOR:\n",BYTE_PER_SECTOR);
        }
       
        return 0;
}

luojiannx

嘿嘿，你的概念早过时了

gvim

这个代码我没有看，但是你要得到 段地址和偏移地址 是和cpu有关的，有的cpu没有分段机制，有的cpu可以选择是否分段，所以，没有任何检测代码的代码不是健壮的代码。

另外，XP对物理设备的访问有保护，除非你写驱动，否则肯定出错。

luojiannx

段地址和偏移可以有很多种答案的
这个你翻翻那些老书就知道了

apollolegend

嵌入汇编取段地址寄存器ds,偏移应该就是&name,但我不知道保护模式下可不可以这样做.

zjneter

我 当然是在x86上写的，各位没看到 下面两个宏是tc2  dos。h中定义的
用来取得段地址和偏移地址
#define FP_OFF(fp) ((unsigned)(fp))
#define FP_SEG(fp) ((unsigned)((unsigned long)(fp) >;>; 16))
可在djgpp中使用 好像有些问题，到底是什么问题呢〉？

zjneter

求各位高手帮忙调试一下程序 谢谢阿

renstone921

既然用的是djgpp,那就按照他的规则来.不要把TC的那一套套在DJGPP的头上.

1. 
   
2. 看一下下面两个函数.
   
3. #include <bios.h>;
   
4. 
   
5. int biosdisk(int cmd, int drive, int head, int track,
   
6.      int sector, int nsects, void *buffer)
   
7. 
   
8. char buffer[512];
   
9. if (biosdisk(2, 0x80, 0, 0, 0, 1, buffer))
   
10.   error("disk");
    
11. 
    
12. #include <bios.h>;
    
13. 
    
14. unsigned _bios_disk(unsigned cmd, struct diskinfo_t *di)
    
15. 
    
16. char record_buffer[512];
    
17. struct diskinfo_t di;
    
18. 
    
19. di.drive    = 0x80;
    
20. di.head     = 0;
    
21. di.track    = 0;
    
22. di.sector   = 1;
    
23. di.nsectors = 1;
    
24. di.buffer   = &record_buffer;
    
25. if ( _bios_disk(_DISK_READ, &di) )
    
26.   puts("Disk error.");
    
27. 
    

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只需要上面两个函数应当就可以解决你的问题了.

另外,要注意的是,在2000-XP上面,你应当使用2.03版以上的.否则会出很多问题.

zjneter

楼上的兄弟误会了
我是要调用bios int 13 的 48h功能取得磁盘驱动器的相关参数
biosdisk（）怎么能达到我的目的呢？

renstone921

1. 
   
2. #include <bios.h>;
   
3. 
   
4. int biosdisk(int cmd, int drive, int head, int track,
   
5.      int sector, int nsects, void *buffer);
   
6. Description
   
7. 
   
8. This function interfaces with the BIOS disk sevice (interrupt 0x13). Please refer to a BIOS reference manual for detailed information about the parameters of this call. All known calls are supported. A sector size of 512 bytes is assumed.
   
9. 0 - reset disk subsystem
   
10. 1 - get disk subsystem status
    
11. 2 - read one or more sectors
    
12. 3 - write one or more sectors
    
13. 5 - format a track
    
14. 6 - format back track
    
15. 7 - format drive
    
16. 8 - get drive parameters
    
17. 9 - initialize drive parameters
    
18. 10 - read long sectors
    
19. 11 - write long sectors
    
20. 12 - seek to cylinder
    
21. 13 - alternate fixed disk reset
    
22. 14 - read test buffer
    
23. 15 - write test buffer
    
24. 16 - test for drive ready
    
25. 17 - recalibrate drive
    
26. 18 - controller RAM diagnostic
    
27. 19 - controller drive diagnostic
    
28. 20 - controller internal diagnostic
    
29. 15 - read fixed disk type
    
30. 22 - read disk change line status
    
31. 23 - set DASD type (pass dasd in nsects)
    
32. 24 - set media type for format
    
33. 
    
34. The first request with more sectors than will fit in the transfer buffer will cause a DOS buffer to be allocated. This buffer is automatically freed when your application exits. Since this buffer is big enough to hold 18 sectors, requests for more sectors than that will fail.
    
35. 
    
36. Request eight returns values in buffer as follows:
    
37. byte 0 = sectors per track (bits 0..5) and top two bits of cylinder (in bits 6..7)
    
38. byte 1 = cyliders (bits 0..7)
    
39. byte 2 = number of drives
    
40. byte 3 = number of heads
    
41. Return Value
    
42. 
    
43. The value of AH returned by the BIOS
    

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The 8th got the driver parameter.