wow, thank you for the prompt response! I think it will get me unstuck On Fri, Sep 20, 2019 at 9:53 PM Mark Olesen <[email protected]> wrote:
> Howdy, > > Your aligning by 16 byte paragraph > > On Fri, Sep 20, 2019 at 7:45 PM Quinton Cook <[email protected]> > wrote: > >> Hello all, >> >> I have recently taken an academic interest in the freedos project. My >> current goal is to understand how the kernel was implemented. >> >> While reading the kernel.asm file located >> in freedos-svn/kernel/branches/jhall/kernel I have inferred that the >> routine "kernel_start" is calculating the overall memory available to the >> system. but I came across a snippet of code that confused me. Starting on >> line 128 >> it goes >> >> mov dx,init_end+15 >> mov cl,4 >> shr dx,cl >> sub ax,dx >> >> why is 15 added to the end of the address of the symbol init_end if you >> just shift the value right by 4, doesn't that just undo the addition? Is it >> related to memory addresses having to be divisible by 16? Segmentation or >> something like that? >> >> Also is that last sub calculating the amount of room needed for the >> kernel? >> >> I hope all is well and get back to me when it is convenient for you, >> thanks >> -- >> *Quinton Cook* >> _______________________________________________ >> Freedos-devel mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/freedos-devel >> > _______________________________________________ > Freedos-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freedos-devel > -- *Quinton Cook*
_______________________________________________ Freedos-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freedos-devel
