From: Stanislav <stl...@gm...> - 2014-12-16 17:59:39
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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 |