Inline assembly under FreeBSD

Unga unga888 at
Mon Apr 7 10:03:54 UTC 2008

Hi all

I'm trying to execute following inline assembly code
in a C function under FreeBSD 7.0:

typedef unsigned char u8;
typedef unsigned short u16;

u8 devno= 0x80;

static int check_extensions(u8 devno)
	u16 ax, bx, cx, dx, di;

	ax = 0x4100;
	bx = 0x55AA;
	dx = devno;
	asm("pushfl; stc; int $0x13; setc %%al; popfl"
	    : "+a" (ax), "+b" (bx), "=c" (cx), "+d" (dx)
	    : : "esi", "edi");

	if ((u8)ax)
		return -1;	/* No extended information */
		return 1;	/* Extended information available */

When it is executing the int $0x13, it crashes with
"Program received signal SIGBUS, Bus error."

Could you guys give me a helping hand to identify
what's the problem?

Input and return values are at:

Thanks in advance.

Kind regards

You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost.

More information about the freebsd-questions mailing list