Messages in this thread | | | Date | Mon, 20 Jun 2005 11:40:24 -0400 (EDT) | From | "Richard B. Johnson" <> | Subject | Re: how to insert an asm instruction in C code and how to compile it |
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On Mon, 20 Jun 2005, Srinivas G. wrote:
> Dear All, > > I am very sorry for asking such a silly question here. > > I have small doubt about ASM code in a C program. Actually I want to > insert some asm instructions in a C program and after that I want to > compile the C program. > > I want to include the following code in a simple C program and compile > it. >
Well, even if you could make the correct assembly, you would not be able to run the BIOS-based program that you show. As soon as you execute the interrupt 0x10, your program will seg-fault because it is an invalid instruction in user-mode code and would even cause an invalid oprand fault in kernel mode.
The second problem with your code is that __all__ of the assembly for the entire procedure must be written in one block, not with seperate "asm" instructions. This is because 'C' isn't going to preserve the values in the registers between "asm" blocks.
> #define printf DbgPrint > > int main() > { > printf("Hello world program!\n"); > return 0; > } > void DbgPrint(char* str,...) > { > volatile USHORT i = 0; > volatile UCHAR sch; > while(str[i]) > { > sch = str[i]; > i ++; > asm mov ah,0x0E; > asm mov al,sch; > > asm cmp al,0ah > asm jne test > asm mov al,0dh //; new line > asm mov bx,07h > asm int 10h > asm mov al,0ah > test: > asm mov bx,0x07 > asm int 0x10 > } > } > > Please let me know how to do it? > > Any links or Howtos are welcome. > Thanks in advance. > > Regards, > Srinivas G > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
Cheers, Dick Johnson Penguin : Linux version 2.6.12 on an i686 machine (5537.79 BogoMips). Notice : All mail here is now cached for review by Dictator Bush. 98.36% of all statistics are fiction. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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