Bonsoir Sebastien! > Since more days, I develop "from scratch" my "task switcher" on FreeDos in > asm/c++ > for preemption.
Have you tried improving the existing TriDOS instead? > * I succeeded to create stack memory in array, for each > tasks added. > * I was not able to "switch" with two stack in asm inline Try to switch only at "smart" moments. For example let programs switch when they try to call int 21, by hooking int 21, but do NOT switch while int 21 is already busy. Check the InDOS flag, as well as related data. The problem is similar to what you get with some TSR / hotkey systems, so a howto for that will also help you to understand task switching. When switching between tasks, you may also want to swap the contents of the SDA (DOS swappable data area) and the DOS stack. Basically it is tricky enough to swap tasks to give MS a good excuse why Windows even refused to do it on non-Microsoft DOS in the beginning... :-p Note that using DJGPP makes things even a lot more complicated, because DJGPP programs always are DPMI tasks in protected mode, usually with CWSDPMI as their protected mode host... So even for simply calling DOS or BIOS from a DJGPP program, you have to be careful to not fall into the gap between protected mode and DOS and DJGPP only does it automatically for you in easy cases. For others, you have to explicitly tell DJGPP how to bridge that gap. > This is my complete code with Batch file for compile with GCC/G++ (DJGPP for > DOS) > http://cpcdos.e-monsite.com/medias/files/task-switch-test.zip Cheers, Eric ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
