Hi Eric, On Sun, Apr 06, 2008 at 11:32:19PM +0200, Eric Auer wrote: > > The hard drive is accessed via PIO mode, so enabling irqs isn't > > required for correct hd operation. I'm guessing bochs bios turns on > > irqs so that the system ticks and other timers don't go unanswered > > Hmm interesting. Then maybe it would be better to keep IRQs off... > > > that the problems stop occuring. Unfortunately, when I enable irqs > > and put tests in the bios ISR routines, I don't see them getting > > called with low stack space... > > Okay but how much stack space do your BIOS IRQ handlers use for > themselves?
Well, that depends on the interrupt. At a minimum, it is currently 30 bytes to enter a C handler. I think I'm going to write a tool to analyze the disassembled code and come up with the max stack usage. > > how much stack space does the freedos ISR routines need... > > Depends. FreeDOS itself does not install any IRQ handlers at all. Okay, that is reassuring. Something is not adding up with the numbers though.. I'll have to look at this further. > > appears that EMM386 is installing a wrapper around int 13 calls > > That is true, but it is odd that the offset of this emm386 int13 > handler seems to the same as the offset of the lbacache one... > Probably a coincidence. I thought EMM386 hooked int-13, and then lbacache hooked int-13 and sent all calls to EMM386, which then passed them on to the BIOS. > > I'm using freedos 1.0 - everything installed from the standard > > cd download. > > Try updating to the versions used in the rugxulo.googlepages.com > (2-3) diskette distro or at least mateusz.viste.free.fr/fdupdate/ Okay, I'll take a look next weekend. > You are right, the stack initially contains the value 0x20 for > each byte, but only 18 bytes left is very little. After all, > the lbacache stack is 64 to 84 bytes smaller than the stack of > the FreeDOS block device driver. I assume I should change this > and let lbacache use 64 to 96 bytes more RAM, right? Opinions? Well, every bit would help. :-) -Kevin ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
