From: angwer <zha...@gm...> - 2014-12-17 01:48:19
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Once I wanted to, but I saw a similar question on the forum with no answer so I drop the idea. But now I decide to have a try. Thanks. On 12/17/2014 01:59 AM, Stanislav wrote: > Hello, > > Did you try to ask the question in the osdev forum ? > I believe the osdev forum audience is more knowledgeable in such kind of > questions. > > Thanks, > Stanislav > > -----Original Message----- > From: angwer [mailto:zha...@gm...] > Sent: Tuesday, December 16, 2014 5:55 PM > To: boc...@li... > Subject: [Bochs-developers] Why code for 8295a still work on APIC platform? > > Hi everyone, I am new here. > > Recently I use bochs as the emulator to learn OS development. I get some > assembly code from a book, which manipulate interrupts. It initialize the > 8295a PIC and IDT. I compile the code and then run it in freedos (since I > have not written a complete boot loader, the book tells me to run it as com > file in freedos, which makes no difference) and all goes well. The PIC is > initialized correctly by sending ICWx and the handler is called when > interrupt occurs. > > But I don't understand why the code can run correctly. I run freedos and the > sample on bochs with the a Pentium 4 cpu which uses xAPIC (I also test on > core 2). I have search a lot and find that xAPIC is different from PIC and > no results tell me they are compatible. (Actully when I read the Intel > manual. I find 8295a can work together with APIC but it seems I can not use > the usual way to initialize it.) So I think the code should not work. I > don't see any code disabling APIC in the sample. > > So my question are: > Why code using 8295a still work on APIC platforms? > Does that mean cpus like Pentium 4 and core 2 still have PICs? And what > about newer cpus? > > Sorry if the question is stupid and thanks everyone in advance. > > ---------------------------------------------------------------------------- > -- > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from > Actuate! Instantly Supercharge Your Business Reports and Dashboards with > Interactivity, Sharing, Native Excel Exports, App Integration & more Get > technology previously reserved for billion-dollar corporations, FREE > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > _______________________________________________ > bochs-developers mailing list > boc...@li... > https://lists.sourceforge.net/lists/listinfo/bochs-developers > |