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182 lines
3.7 KiB
182 lines
3.7 KiB
3 years ago
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<HTML
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><HEAD
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><TITLE
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>About the code</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
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REL="HOME"
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TITLE="Bochs Developers Guide"
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HREF="index.html"><LINK
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REL="PREVIOUS"
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TITLE="Ideas for other sections"
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HREF="other.html"><LINK
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REL="NEXT"
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TITLE="Directory Structure"
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HREF="directory-structure.html"></HEAD
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><BODY
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CLASS="CHAPTER"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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SUMMARY="Header navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>Bochs Developers Guide</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="other.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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></TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="directory-structure.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="CHAPTER"
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><H1
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><A
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NAME="ABOUT-THE-CODE"
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></A
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>Chapter 2. About the code</H1
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><DIV
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CLASS="SECTION"
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><H1
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CLASS="SECTION"
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><A
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NAME="CODE-OVERVIEW"
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>2.1. Overview</A
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></H1
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><P
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>The initial versions of some sections in this chapter are based on a document
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written by Peter "Firefly" Lund. It was added and updated in January 2006.</P
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><P
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>The Bochs virtual PC consists of many pieces of hardware. At a bare minimum
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there are always a CPU, a PIT (Programmable Interval Timer), a PIC
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(Programmable Interrupt Controller), a DMA controller, some memory (this
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includes both RAM and BIOS ROMs), a video card (usually VGA), a keyboard port
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(also handles the mouse), an RTC with battery backed NVRAM, and some extra
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motherboard circuitry.</P
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><P
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>There might also be a NE2K ethernet card, a PCI controller, a Sound Blaster 16,
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an IDE controller (+ harddisks/CDROM), a SCSI controller (+ harddisks), a
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floppy controller, an APIC ..</P
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><P
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>There may also be more than one CPU.</P
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><P
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>Most of these pieces of hardware have their own C++ class - and if Bochs is
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configured to have more than one piece of a type of hardware, each will have
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its own object.</P
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><P
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>The pieces of hardware communicates over a couple of buses with each other -
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some of the things that the buses carry are reads and writes in memory space,
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reads and writes in I/O space, interrupt requests, interrupt acknowledges, DMA
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requests, DMA acknowledges, and NMI request/acknowledge. How that is simulated
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is explained later.<IMG
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SRC="../images/undercon.png"></P
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><P
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>Other important pieces of the puzzle are: the options object (reads/writes
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configuration files, can be written to and queried while Bochs is running) and
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the GUI object. There are many different but compatible implementations of the
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GUI object, depending on whether you compile for X (Unix/Linux), Win32,
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Macintosh (two versions: one for Mac OS X and one for older OS's), BeOS, Amiga,
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etc.</P
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><P
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>And then there is the supporting cast: debugger, config menu, panic handler,
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disassembler, tracer, instrumentation.</P
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></DIV
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="other.html"
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|
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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|
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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|
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ACCESSKEY="H"
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|
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>Home</A
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|
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></TD
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><TD
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|
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WIDTH="33%"
|
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|
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ALIGN="right"
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|
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VALIGN="top"
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|
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><A
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|
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HREF="directory-structure.html"
|
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|
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ACCESSKEY="N"
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|
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>Next</A
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|
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></TD
|
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|
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></TR
|
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|
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><TR
|
||
|
|
><TD
|
||
|
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WIDTH="33%"
|
||
|
|
ALIGN="left"
|
||
|
|
VALIGN="top"
|
||
|
|
>Ideas for other sections</TD
|
||
|
|
><TD
|
||
|
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WIDTH="34%"
|
||
|
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ALIGN="center"
|
||
|
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VALIGN="top"
|
||
|
|
> </TD
|
||
|
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><TD
|
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|
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WIDTH="33%"
|
||
|
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ALIGN="right"
|
||
|
|
VALIGN="top"
|
||
|
|
>Directory Structure</TD
|
||
|
|
></TR
|
||
|
|
></TABLE
|
||
|
|
></DIV
|
||
|
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></BODY
|
||
|
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></HTML
|
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>
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