Re: x86 D flag: what's its status thru the program?
Lukasz Michal Rak <[email protected]> Mon, 5 Jul 2004 15:23:44 +0200 (CEST)
| Newsgroups | org.kernel.vger.linux-gcc |
|---|---|
| Message-ID | <[email protected]> |
Hi all! The convention is that the D flag in IA32 is cleared. So if you call a subroutine you have to clear D flag before making call. The subroutine can change the state of D flag, but before returning the routine has to clear the D flag. Hope I helped. Regards, Lukasz > Is this Direction flag (for the movs instructions) has some assumed > value (say, as after cld)? I ask because the many program sources > show interesting behaviour: from one side, this flag is always set > before the string insns (cld or std), but from the other side, if the > programs does std then it always does cld after. So, nobody leaves it > set, but nevertheless, everybody set it clear. Why? > - > To unsubscribe from this list: send the line "unsubscribe linux-gcc" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html >