> M> I see that interrupt vectors up through 3F are modified. > > Just for safety - for example, if some program will try to call mouse > API (INT33) while mouse driver not installed.
Understood >>> M> For example, the timer ticker interrupt at 1Ch (or 08h). >>> For timer operation DOS uses BIOS. > M> One can read the timer tick out of the BIOS Data Area, but in order to > get > M> interrupt notification of timer ticks one must hook int 1Ch (or 08h) > > DOS doesn't mess with this. > > M> It seems to me that FreeDOS must hook into the BIOS ticker interrupt in > M> order to get notification of ticks. > > Why it should get notifications?! I assumed that it wanted notifications to maintain its own DOS clock. > M> Probably 1Ch ... but that is not > M> happening in this code ... so that makes me wonder whether or not there > is > M> someplace else in the FreeDOS code that is hooking the timer interrupt. > > Again: DOS uses exclusively BIOS for date/time services and there are > no functions, which require from DOS to mess with timer notifications. OK ... good. > M> I will investigate this a little further. > M> There is also a CMOS timer interrupt at int 70h. Less likely that this > is > M> being used by FreeDOS. > > Of course. > >>> M> Q: What is the highest numbered interrupt that is used by >>> FreeDOS/MS-DOS ? >>> What mean "uses"? You mean, through which presents own services? >>> INT2F. > M> Sorry I was not clear. > M> I mean ... What is the highest numbered interrupt vector that is > M> 'modified' by FreeDOS. > > As you may see from sources, highest "modified" is INT3F, but this > modification is dummy (just for safety). Highest interrupt, which related > to DOS (kernel) services is a INT2F. Excellent. Thank you, Michael ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid0944&bid$1720&dat1642 _______________________________________________ Freedos-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freedos-devel
