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This is the top level file for the Bochs Developers Manual.
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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN" [

<!-- include definitions that are common to all Bochs documentation -->
<!ENTITY % bochsdefs SYSTEM "../include/defs.sgm">
%bochsdefs;

]>
<book>
<bookinfo>
   <title>Bochs Developers Guide</title>
   <authorgroup>
   <author><firstname>Kevin</firstname><surname>Lawton</surname></author>
   <author><firstname>Bryce</firstname><surname>Denney</surname></author>
   <author><firstname>Christophe</firstname><surname>Bothamy</surname></author>
   <editor><firstname>Michael</firstname><surname>Calabrese</surname></editor>
   </authorgroup>
</bookinfo>

<!-- *************************************************************** -->
<chapter id="resources"><title>Resources for developers</title>
<para>
The development guide describes resources that are intended for developers
in particular.  Many Bochs resources are also covered in the User Guide,
including compile instructions, bochsrc options, how to find the mailing
lists, etc.
</para>


<section id="cvs-write-access-setup"><title>Setting up CVS write access</title>
<para>
If you are an official SourceForge developer, then you can use CVS with write
access.  The CVS contains the most recent copy of the source code, and with
write access you can upload any changes you make to the CVS server for others
to use.  A few extra steps are required the first time you use CVS write
access.
</para>

<section><title>Install ssh and cvs</title>
<para>
First you need to install both cvs (Concurrent Version System) and ssh (Secure
Shell).  These are already installed on many UNIX systems and also Cygwin
(win32 platform).  If not, you can install binaries or compile cvs and ssh
yourself.  The links below should help you get going.
</para>
<itemizedlist>
<listitem> <para> CVS software and instructions are available at <ulink url="http://www.cvshome.org">www.cvshome.org</ulink>. </para> </listitem>
<listitem> <para> A free version of secure shell called OpenSSH is at <ulink url="http://www.openssh.org">www.openssh.org</ulink>. </para> </listitem>
<listitem> <para> OpenSSH requires a library called OpenSSL from <ulink url="http://www.openssl.org">www.openssl.org</ulink>.  Be sure to install OpenSSL before trying to compile OpenSSH. </para> </listitem>
</itemizedlist>
</section>

<section><title>ssh to cvs.sf.net</title>
<para>
Next, you need to use secure shell to connect to cvs.sf.net.  This step is a
little strange, because you can't actually log in and get a shell prompt.  All
that will happen, when you get the username and password right, is that it
will create a home directory on that machine for you.  That's it!  If you try
it again, it will say "This is a restricted Shell Account.  You cannot execute
anything here."   At this point, you've succeeded and you never have to do
this step again, ever.

<screen>
  ssh <replaceable>sfusername</replaceable>@bochs.cvs.sf.net
</screen>
</para>

<para>
Replace <replaceable>sfusername</replaceable> with your Source Forge username,
of course.  The first time, you will probably get a message like
<screen>
The authenticity of host 'cvs.sf.net' can't be established.
Are you sure you want to continue?</screen>

Just type yes.  When it asks for a password, be sure to type your source
forge password.  If you have trouble logging in, be sure to use your SOURCE
FORGE username and password in the ssh line, which isn't necessarily the same
as your local username and password.  Add the "-v" option to ssh to see more
information about what is failing.  If you have ssh version 2, it is possible
that you might need to add "-1" to the ssh command to force it to use the
version 1 protocol.  </para> </section>

<section><title>Set CVS_RSH environment variable to ssh</title>
<para>
Every time you connect to the Source Forge CVS server (including cvs update,
stat, commit, etc.), you must set the CVS_RSH environment variable to ssh.  So
just take the time now to add one of these lines to your .bashrc/.cshrc, so
that the CVS_RSH setting will be there every time you log in.
</para>

<screen>
  export CVS_RSH=ssh           (bash syntax)
  setenv CVS_RSH ssh           (csh syntax)
</screen>
</section> <!--end of "Set environment variable"-->

<section><title>cvs checkout</title>
<para>
Finally, you should be able to do the checkout!  If you already have a Bochs
subdirectory directory, move it out of the way because the checkout will
overwrite it.
</para>

<screen>
  export CVSROOT=":ext:<replaceable>sfusername</replaceable>@bochs.cvs.sourceforge.net:/cvsroot/bochs"
  cvs -z3 checkout bochs
  <replaceable>sfusername</replaceable>@bochs.cvs.sourceforge.net's password:        <replaceable><--type your password</replaceable>
</screen>

<para>
In the CVSROOT variable, replace <replaceable>sfusername</replaceable> with your SF username.  There's
no need to add CVSROOT to your rc files because CVS will remember it
after the checkout.  The -z3 (optional) just adds some compression to make
the checkout go faster.  Once all the files have been downloaded, you will
have a Bochs directory which is checked out with write access!
</para>
</section> <!-- end cvs checkout -->

</section> <!-- end setting up cvs write access -->

<section id="using-cvs-write-access"><title>Using CVS write access</title>

<section><title>Checking in files</title>
<para>
Once you have a Bochs directory with cvs write access, you can compile the
files, edit them, test them, etc.  See the documentation section, "Tracking
the source code with CVS" for more info on CVS, in the User Manual.
(FIXME: add cross reference) But what's new and different is that you can now
do cvs commits.  When a file is all fixed and ready to share with the rest of
the world, you run a commit command to upload your version to the server.
First, it's good to do a cvs update to make sure nobody else has changed it
since you downloaded it last.
</para>

<screen>
  $ cvs update file.cc
  <replaceable>sfusername</replaceable>@bochs.cvs.sf.net's password:        <replaceable><--type your password</replaceable>
  $ cvs commit file.cc
  <replaceable>sfusername</replaceable>@bochs.cvs.sf.net's password:        <replaceable><--type your password</replaceable>
  [editor opens. type log message, save, and exit.]
</screen>

<para>
When CVS starts an editor, The default is usually vi.  If you want a different
editor, set the EDITOR environment variable to the name of your preferred
editor.  When you're done, just save the file and quit the editor.  Unless
there's some problem, you will see a message that says what the new revision
number for the file is, and then "done".  If while you're editing the log
message, you decide that you don't want to commit after all, don't save the
file.  Quit the editor, and when it asks where the log message went, tell it
to abort.
</para>

<para>
Here is an example of a successful checkin:

<screen>
  $ cvs commit misc.txt
  <replaceable>sfusername</replaceable>@bochs.cvs.sf.net's password:        <replaceable><--type your password</replaceable>
  [edit log msg]
  Checking in misc.txt;
  /cvsroot/bochs/bochs/doc/docbook/misc.txt,v  <--  misc.txt
  new revision: 1.6; previous revision: 1.5
  done
</screen>

And here is an aborted one:

<screen>
  $ cvs commit misc.txt
  <replaceable>sfusername</replaceable>@bochs.cvs.sf.net's password:        <replaceable><--type your password</replaceable>
  [quit editor without saving]
  Log message unchanged or not specified
  a)bort, c)ontinue, e)dit, !)reuse this message unchanged for remaining dirs
  Action: a
  cvs [commit aborted]: aborted by user
</screen>

</para>
</section> <!--end of "Checking in Files" -->

</section> <!--end of "Using CVS write access" -->

      <section id="trackers"><title>SourceForge bug, feature, and patch trackers</title>
         <para>
	 &FIXME;
         </para>
      </section>

<section id="other"><title>Ideas for other sections</title>
<para>
<screen>
Ideas:
- how to browse code with cvsweb
- how to find an identifier, variable, or specific text in the code
- how to make patches with CVS
</screen>
</para>
</section>

</chapter>

<chapter id="about-the-code"><title>About the code</title>

<section id="code-overview"><title>Overview</title>
<para>
The initial versions of some sections in this chapter are based on a document
written by Peter "Firefly" Lund. It was added and updated in January 2006.
</para>
<para>
The Bochs virtual PC consists of many pieces of hardware. At a bare minimum
there are always a CPU, a PIT (Programmable Interval Timer), a PIC
(Programmable Interrupt Controller), a DMA controller, some memory (this
includes both RAM and BIOS ROMs), a video card (usually VGA), a keyboard port
(also handles the mouse), an RTC with battery backed NVRAM, and some extra
motherboard circuitry.
</para>
<para>
There might also be a NE2K ethernet card, a PCI controller, a Sound Blaster 16,
an IDE controller (+ harddisks/CDROM), a SCSI controller (+ harddisks), a
floppy controller, an APIC ..
</para>
<para>
There may also be more than one CPU.
</para>
<para>
Most of these pieces of hardware have their own C++ class - and if Bochs is
configured to have more than one piece of a type of hardware, each will have
its own object.
</para>
<para>
The pieces of hardware communicates over a couple of buses with each other -
some of the things that the buses carry are reads and writes in memory space,
reads and writes in I/O space, interrupt requests, interrupt acknowledges, DMA
requests, DMA acknowledges, and NMI request/acknowledge. How that is simulated
is explained later.&FIXME;
</para>
<para>
Other important pieces of the puzzle are: the options object (reads/writes
configuration files, can be written to and queried while Bochs is running) and
the GUI object. There are many different but compatible implementations of the
GUI object, depending on whether you compile for X (Unix/Linux), Win32,
Macintosh (two versions: one for Mac OS X and one for older OS's), BeOS, Amiga,
etc.
</para>
<para>
And then there is the supporting cast: debugger, config menu, panic handler,
disassembler, tracer, instrumentation.
</para>
</section>

<section id="directory-structure"><title>Directory Structure</title>
<para>
<table>
<title>Directory structure</title>
<tgroup cols="2">
<thead>
<row>
<entry>Location</entry>
<entry>Meaning</entry>
</row>
</thead>
<tbody>
<row><entry>bios</entry><entry>System and VGA BIOS images, system BIOS sources and makefile</entry></row>
<row><entry>build</entry><entry>additional stuff required for building Bochs on different platforms</entry></row>
<row><entry>bx_debug</entry><entry>the builtin Bochs debugger</entry></row>
<row><entry>cpu</entry><entry>the cpu emulation sources</entry></row>
<row><entry>disasm</entry><entry>the disassembler for the Bochs debugger</entry></row>
<row><entry>doc/docbook</entry><entry>the Bochs documentation in DocBook format</entry></row>
<row><entry>doc/man</entry><entry>Bochs manual pages</entry></row>
<row><entry>docs-html</entry><entry>old Bochs documentation in HTML (will be replaced by DocBook)</entry></row>
<row><entry>dynamic</entry><entry>empty directory (reserved for dynamic translation code)</entry></row>
<row><entry>font</entry><entry>the default VGA font used by most of the display libraries</entry></row>
<row><entry>fpu</entry><entry>the fpu emulation sources</entry></row>
<row><entry>gui</entry><entry>display libraries (guis), the simulator interface and text mode config interface</entry></row>
<row><entry>gui/bitmaps</entry><entry>bitmaps for the headerbar</entry></row>
<row><entry>gui/keymaps</entry><entry>keymaps for the keyboard mapping feature</entry></row>
<row><entry>host</entry><entry>host specific drivers (currently only used by the pcidev kernel module for Linux)</entry></row>
<row><entry>instrument</entry><entry>directory tree for the instrumentation feature</entry></row>
<row><entry>iodev</entry><entry>standard PC devices, PCI devices, lowlevel networking and sound drivers</entry></row>
<row><entry>memory</entry><entry>memory management and ROM loader</entry></row>
<row><entry>misc</entry><entry>useful utilities (e.g. bximage, bxcommit, niclist)</entry></row>
<row><entry>misc/sb16</entry><entry>tool to control the SB16 emulation from the guest side</entry></row>
<row><entry>patches</entry><entry>pending patches</entry></row>
<row><entry>plex86</entry><entry>plex86 directory structure (possibly outdated)</entry></row>
</tbody>
</tgroup>
</table>
</para>
</section>

<section id="emulator-objects"><title>Emulator Objects</title>
<section><title>Weird macros and other mysteries</title>
<para>
Bochs has many macros with inscrutable names. One might even go as far as to
say that Bochs is macro infested.
Some of them are gross speed hacks, to cover up the slow speed that C++ causes.
Others paper over differences between the simulated PC configurations.
Many of the macros exhibit the same problem as C++ does: too much stuff happens
behind the programmer's back. More explicitness would be a big win.
</para>
</section>
<section id="static-methods-hack"><title>Static methods hack</title>
<para>
C++ methods have an invisible parameter called the this pointer - otherwise the
method wouldn't know which object to operate on. In many cases in Bochs, there
will only ever be one object - so this flexibility is unnecessary. There is a
hack that can be enabled by #defining BX_USE_CPU_SMF to 1 in <filename>config.h
</filename> that makes most methods static, which means they have a "special
relationship" with the class they are declared in but apart from that are
normal C functions with no hidden parameters. Of course they still need access
to the internals of an object, so the single object of their class has a globally
visible name that these functions use. It is all hidden with macros.
</para>
<para>
Declaration of a class, from iodev/pic.h:
</para>
<screen>
...
#if BX_USE_PIC_SMF
#  define BX_PIC_SMF  static
#  define BX_PIC_THIS thePic->
#else
#  define BX_PIC_SMF
#  define BX_PIC_THIS this->
#endif
...
class bx_pic_c : public bx_pic_stub_c {

public:
  bx_pic_c(void);
  ~bx_pic_c(void);
...
  BX_PIC_SMF void   service_master_pic(void);
  BX_PIC_SMF void   service_slave_pic(void);
  BX_PIC_SMF void   clear_highest_interrupt(bx_pic_t *pic);
  };
</screen>
<para>
And iodev/pic.cc:
</para>
<screen>
...
#define LOG_THIS thePic->
...
bx_pic_c *thePic = NULL;
...
void bx_pic_c::service_master_pic(void)
{
  Bit8u unmasked_requests;
  int irq;
  Bit8u isr, max_irq;
  Bit8u highest_priority = BX_PIC_THIS s.master_pic.lowest_priority + 1;
  if(highest_priority > 7)
    highest_priority = 0;

  if (BX_PIC_THIS s.master_pic.INT) { /* last interrupt still not acknowleged */
    return;
  }

  if (BX_PIC_THIS s.master_pic.special_mask) {
    /* all priorities may be enabled.  check all IRR bits except ones
     * which have corresponding ISR bits set
     */
    max_irq = highest_priority;
  }
  else { /* normal mode */
    /* Find the highest priority IRQ that is enabled due to current ISR */
    isr = BX_PIC_THIS s.master_pic.isr;
...
}
...
</screen>
<para>
Ugly, isn't it? If we use static methods, methods prefixed with BX_PIC_SMF are
declared static and references to fields inside the object, which are prefixed
with BX_PIC_THIS, will use the globally visible object, thePic->. If we don't
use static methods, BX_PIC_SMF evaluates to nothing and BX_PIC_THIS becomes this->.
Making it evaluate to nothing would be a lot cleaner, but then the scoping rules
would change slightly between the two Bochs configurations, which would be a load
of bugs just waiting to happen. Some classes use BX_SMF, others have their own
version of the macro, like BX_PIC_SMF above.
</para>
</section>
<section id="cpu-mem-objects"><title>CPU und memory objects in UP/SMP configurations</title>
<para>
The CPU class is a special case of the above: if Bochs is simulating a uni-
processor machine then there is obviously only one bx_cpu_c object and the
static methods trick can be used. If, on the other hand, Bochs is simulating an
smp machine then we can't use the trick. The same seems to be true for memory:
for some reason, we have a memory object for each CPU object. This might become
relevant for NUMA machines, but they are not all that common -- and even the
existing IA-32 NUMA machines bend over backwards to hide that fact: it should
only be visible in slightly worse timing for non-local memory and non-local
peripherals. Other than that, the memory map and device map presented to each
CPU will be identical.
</para>
<para>
In a UP configuration, the CPU object is declared as bx_cpu. In an SMP
configuration it will be an array of pointers to CPU objects (bx_cpu_array[]).
For memory that would be bx_mem and bx_mem_array[], respectively.
Each CPU object contains a pointer to its associated memory object.
Access of a CPU object often goes through the BX_CPU(x) macro, which either
ignores the parameter and evaluates to &amp;bx_cpu, or evaluates to bx_cpu_array
[n], so the result will always be a pointer. The same goes for BX_MEM(x).
If static methods are used then BX_CPU_THIS_PTR evaluates to BX_CPU(0)->. Ugly,
isn't it?
</para>
</section>
<section id="config-parameter-tree"><title>The configuration parameter tree</title>
<para>
Starting with version 1.3, the Bochs configuration parameters are stored in parameter
objects. These objects have get/set methods with min/max checks and it is possible
to define parameter handlers to perform side effects and to override settings.
Each parameter type has it's own object type with specific features (numeric,
boolean, enum, string and file name). A special object type containing a list of
parameters is designed for building and managing configuration menus or dialogs
automatically. In the original implementation the parameters could be accessed
only with their unique id from a static list or a special structure containing
pointers to all parameters.
</para>
<para>
Starting with version 2.3, the Bochs parameter object handling has been rewritten
to a parameter tree. There is now a root list containing child lists, and these
lists can contain lists or parameters and so on. The parameters are now accessed
by a name build from all the list names in the path and finally the parameter
name separated by periods.
<screen>
Bit32u megs = SIM->get_param_num("memory.standard.ram.size")->get();
</screen>
</para>
<para>
The example above shows how to get the memory size in megabytes from the simulator
interface. In the root list (".") there is child list named "memory" containing
a child list "standard". It's child list "ram" contains the numeric parameter type
"size". The SIM->get_param_num() methods returns the object pointer and the get()
method returns the parameter value.
</para>
<para>
The table below shows all parameter types used by the Bochs configuration interface.
<table>
<title>Parameter types</title>
<tgroup cols="2">
<thead>
<row>
<entry>Type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>bx_object_c</entry>
<entry>Base class for all the other parameter types. It contains the unique parameter id and the object type value.</entry>
</row>
<row>
<entry>bx_param_c</entry>
<entry>Generic parameter class. It contains the name, label, description and the input/output formats.</entry>
</row>
<row>
<entry>bx_param_num_c</entry>
<entry>Numerical (decimal/hex) config settings are stored in this parameter type.</entry>
</row>
<row>
<entry>bx_param_bool_c</entry>
<entry>This parameter type is based on bx_param_num_c, but it is designed for boolean values. A dependency
list can be defined to enable/disable other parameters depending on the value change.</entry>
</row>
<row>
<entry>bx_param_enum_c</entry>
<entry>Based on bx_param_num_c this parameter type contains a list of valid values.</entry>
</row>
<row>
<entry>bx_param_string_c</entry>
<entry>Configuration strings are stored in this type of parameter.</entry>
</row>
<row>
<entry>bx_param_filename_c</entry>
<entry>Based on bx_param_string_c this parameter type is used for file names.</entry>
</row>
<row>
<entry>bx_list_c</entry>
<entry>Contains a list of pointers to parameters (bx_param_*_c and bx_list_c).
In the config interface it is used for menus/dialogs.</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
</section>
<section id="save-restore"><title>The save/restore feature</title>
<para>
The save/restore feature is based on an extension to the parameter tree concept.
A subtree (list) called "bochs" appears in the root of the parameter tree
and some new "shadow" parameter types store pointers to values instead of the values
itself. All the hardware objects have register_state() methods to register pointers
to the device registers and switches that need to be saved. The simulator interface
saves the registered data in text format to the specified folder (usually one file
per item in the save/restore list). Large binary arrays are registered with a
special parameter type, so they are saved as separate files.
</para>
<para>
The table below shows the additional parameter types for save/restore.
<table>
<title>Save/restore parameter types</title>
<tgroup cols="2">
<thead>
<row>
<entry>Type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>bx_shadow_num_c</entry>
<entry>Based on bx_param_num_c this type stores a pointer to a numerical variable.</entry>
</row>
<row>
<entry>bx_shadow_bool_c</entry>
<entry>This parameter type stores a pointer to a boolean variable.</entry>
</row>
<row>
<entry>bx_shadow_data_c</entry>
<entry>This special parameter type stores pointer size of a binary array.</entry>
</row>
</tbody>
</tgroup>
</table>
It is also possible to use the bx_param_num_c object with parameter save/restore
handlers. With this special way several device settings can be save to and restored
from one single parameter.
</para>
<para>
All devices can uses these two save/restore specific methods:
<itemizedlist>
<listitem><para>register_state() is called after the device init() to register the device members for save/restore</para></listitem>
<listitem><para>after_restore_state() is an optional method to do things directly after restore</para></listitem>
</itemizedlist>
</para>
</section>
</section>

     <section id="configure-scripting"><title>Configure Scripting</title>
      <para>
      &FIXME;
      configure script, makefiles, header files
      </para>
     </section>

      <section id="logfunctions"><title>Log Functions</title>
      <para>
      &FIXME;
      log functions: what is a panic, what is an error, etc.
      </para>
      </section>

      <section id="timers"><title>timers</title>
      <para>
      &FIXME;
      </para>
      </section>

<section id="cmos-map"><title>Bochs's CMOS map</title>
<para>
In addition to the default CMOS RAM layout, the Bochs BIOS uses some additional
registers for harddisk parameters and the boot sequence. The following table
shows all CMOS registers and their meaning.
</para>
<para>
<screen>
Legend:
S	- set by the emulator (Bochs)
Q	- set by the emulator (Qemu)
B	- set by the bios
U	- unused by the bios

LOC	NOTES	MEANING
0x00	S	rtc seconds
0x01	B	second alarm
0x02	S	rtc minutes
0x03	B	minute alarm
0x04	S	rtc hours
0x05	B	hour alarm

0x06	S,U	day of week
0x07	S,B	date of month
0x08	S,B	month
0x09	S,B	year

0x0a	S,B	status register A
0x0b	S,B	status register B
0x0c	S	status register C
0x0d	S	status register D

0x0f	S	shutdown status
    values:
	0x00: normal startup
	0x09: normal
	0x0d+: normal
	0x05: eoi ?
	else: unimpl

0x10	S	fd drive type (2 nibbles: high=fd0, low=fd1)
    values:
	1: 360K 5.25"
	2: 1.2MB 5.25"
	3: 720K 3.5"
	4: 1.44MB 3.5"
	5: 2.88MB 3.5"

!0x11	configuration bits!!

0x12	S	how many disks first (hd type)

!0x13	advanced configuration bits!!

0x14	S,U	equipment byte (?)
	bits	where		what
	7-6	floppy.cc
	5-4	vga.cc		0 = vga
	2	keyboard.cc	1 = enabled
	0	floppy.cc

0x15	S,U	base memory - low
0x16	S,U	base memory - high

0x17	S,U	extended memory in k - low
0x18	S,U	extended memory in k - high

0x19	S	hd0: extended type
0x1a	S	hd1: extended type

0x1b	S,U	hd0:cylinders - low
0x1c	S,U	hd0:cylinders - high
0x1d	S,U	hd0:heads
0x1e	S,U	hd0:write pre-comp - low
0x1f	S,U	hd0:write pre-comp - high
0x20	S,U	hd0:retries/bad_map/heads>8
0x21	S,U	hd0:landing zone - low
0x22	S,U	hd0:landing zone - high
0x23	S,U	hd0:sectors per track

0x24	S,U	hd1:cylinders - low
0x25	S,U	hd1:cylinders - high
0x26	S,U	hd1:heads
0x27	S,U	hd1:write pre-comp - low
0x28	S,U	hd1:write pre-comp - high
0x29	S,U	hd1:retries/bad_map/heads>8
0x2a	S,U	hd1:landing zone - low
0x2b	S,U	hd1:landing zone - high
0x2c	S,U	hd1:sectors per track

0x2d	S	boot from (bit5: 0:hd, 1:fd)

0x2e	S,U	standard cmos checksum (0x10->0x2d) - high
0x2f	S,U	standard cmos checksum (0x10->0x2d) - low

0x30	S	extended memory in k - low
0x31	S	extended memory in k - high

0x32	S	rtc century

0x34	S	extended memory in 64k - low
0x35	S	extended memory in 64k - high

0x37	S	ps/2 rtc century (copy of 0x32, needed for winxp)

0x38	S	eltorito boot sequence + boot signature check
	bits
	0	floppy boot signature check (1: disabled, 0: enabled)
	7-4	boot drive #3 (0: unused, 1: fd, 2: hd, 3:cd, else: fd)

0x39	S	ata translation policy - ata0 + ata1
	bits
	1-0	ata0-master (0: none, 1: LBA, 2: LARGE, 3: R-ECHS)
	3-2	ata0-slave
	5-4	ata1-master
	7-6	ata1-slave

0x3a	S	ata translation policy - ata2 + ata3 (see above)

0x3d	S	eltorito boot sequence (see above)
	bits
	3-0	boot drive #1
	7-4	boot drive #2
0x5b	Q	extra memory above 4GB
0x5f	Q	number of processors
</screen>
</para>
</section>

<section id="sb16-emulation-basics"> <!-- start of SB16 section-->

<title>Sound Blaster 16 Emulation</title>
<note><para>
  A little more up-to-date version of the user related part of this section is
  available in the <ulink url="../user/sb16-emulation.html">user guide</ulink>.
</para></note>
<para>
Sound Blaster 16 (SB16) emulation for Bochs was written and donated by
Josef Drexler, who has a
<ulink url="http://publish.uwo.ca/~jdrexler/bochs/">web page</ulink> on the topic.
  The entire set of his SB16 patches have been integrated into
Bochs, however, so you can find everything you need here.
</para>

<para>
SB16 Emulation has been tested with several soundcards and versions of Linux.  Please give
Josef <ulink url="mailto:jdrexler@julian.uwo.ca">feedback</ulink> on
whether is does or doesn't work on your combination of software and hardware.
</para>

<section><title>How well does it work?</title>
<para>
Right now, MPU401 emulation is next to perfect. It supports UART
and SBMIDI mode, because the SB16's MPU401 ports can't do anything else as well.
</para>

<para>
The digital audio basically works, but the emulation is too slow for fluent
output unless the application doesn't do much in the background (or the
foreground, really). The sound tends to looping or crackle on slower
computer, but the emulation appears to be correct. Even a MOD
player works, although only for lower sampling speeds.
</para>
<para>
Also, the MIDI data running through the MPU401 ports can be written
into a SMF, that is the standard midi file. The wave output
can be written into a VOC file, which has a format defined by
Creative Labs. This file format can be converted to WAV by
sox for example.
</para>
</section>

<section><title>Output to a sound card</title>

<para>
Output is supported on Linux and Windows 95 at the moment.
On Linux, the output goes to any file or device. If you have a
wavetable synthesizer, midi can go to /dev/midi00, otherwise you may need
a midi interpreter. For example, the midid program from the
DosEmu project would work. Wave output should go to /dev/dsp.
These devices are assumed to be OSS devices, if they're not
some of the ioctl's might fail.
On Windows, midi and output goes to the midi mapper and the wave mapper,
respectively. A future version might have selectable output devices.
</para>
</section>

<section><title>Installation on Linux</title>

<para>
<emphasis>Prerequisites:</emphasis>
</para>

<para>
A wavetable synthesizer on /dev/midi00 and a working /dev/dsp if you want real time music and sound, otherwise output to midi and wave files is also possible.
Optionally, you can use a software midi interpreter, such as the midid program from the DosEmu project instead of /dev/midi00.
</para>
</section>

<section><title>Configuring Bochs</title>

<para>
There are a few values in config.h that are relevant to the sound functions.
Edit config.h after running configure, but before compiling.
</para>

<para>
BX_USE_SB16_SMF should be 1 unless you intend to have several sound cards
running at the same time.
</para>

<para>
BX_SOUND_OUTPUT_C is the name of the class used for output.  The default is
to have no output functions, so you need to change this if you want any sound.
The following are supported at the moment:
</para>

<programlisting>
        bx_sound_linux_c    for output to /dev/dsp and /dev/midi00 on Linux
                            (and maybe other OSes that use the OSS driver)
        bx_sound_windows_c  for output to the midi and wave mapper of
                            Windows 3.1 and higher.
        bx_sound_output_c   for no output at all.
</programlisting>

<para>
Setup the SB16 emulation in your .bochsrc, according to instructions
in that file.
</para>
</section>

<section><title>Runtime configuration</title>

<para>
The source for the SB16CTRL program that is used to modify
the runtime behaviour of the SB16 emulator is included in
misc/sb16. You can compile it or download the
<ulink url="http://publish.uwo.ca/~jdrexler/bochs/">executable</ulink>.
</para>

<para>
See the section "Sound Blaster 16 Emulation" in the user documentation for
information about the commands of SB16CTRL.
</para>
</section>

<section><title>Features planned for the future</title>
<itemizedlist>
<listitem><para>Ports to more OS's, but I can't do this myself</para></listitem>
<listitem><para>Finishing the OPL3 FM emulation by translating the music to midi data</para></listitem>
</itemizedlist>
</section>

<section>
<title>Description of the sound output classes</title>

<para>
This file is intended for programmers who would like to port the sound
output routines to their platform. It gives a short outline what services
have to be provided.
</para>
<para>
You should also have a look at the exisiting files, <emphasis>SOUNDLNX.CC</emphasis>
for Linux and <emphasis>SOUNDWIN.CC</emphasis> for Windows and their respective
header files to get an idea about how these things really work.
</para>
</section>

<section><title>Files</title>

<para>
The main include file is <emphasis>bochs.h</emphasis>. It has all definitions
for the system-independent functions that the SB16 emulation uses, which
are defined in <emphasis>sb16.h</emphasis>.
</para>

<para>
Additionally, every output driver will have an include file, which
should be included at the end of sb16.h to allow the emulator
to use that driver.
</para>

<para>
To actually make the emulator use any specific driver,
<emphasis>BX_SOUND_OUTPUT_C</emphasis> has to be set to the name of the respective
output class.
</para>

<para>
Note that if your class contains any system-specific statements,
include-files and so on, you should enclose both the include-file and
the CC-file in an <emphasis>#if defined</emphasis> (OS-define) construct.
Also don't forget to add your file to the object list in
iodev/Makefile and iodev/Makefile.in.
</para>
</section>

<section><title>Classes</title>

<para>
The following classes are involved with the SB16 emulation:
</para>
<itemizedlist>
<listitem><para>
<emphasis>bx_sb16_c</emphasis> is the class containing the emulator itself, that
is the part acting on port accesses by the application, handling the
DMA transfers and so on. It also prepares the data for the output
classes.
</para></listitem>

<listitem><para>
<emphasis>bx_sound_output_c</emphasis> is the base output class. It has all
the methods used by the emulator, but only as stubs and does not
actually produce any output. These methods are then called by
the emulator whenever output is necessary.
</para></listitem>

<listitem><para>
<emphasis>bx_sound_OS_c</emphasis> is derived from
<emphasis>bx_sound_output_c</emphasis>. It contains the code to generate
output for the <emphasis>OS</emphasis> operating system.
It is necessary to override all
the methods defined in the base class, unless virtual functions
are used. Note that this should remain an option, so try to
override all methods, even if only as stubs. They should be
declared <emphasis>virtual</emphasis> if and only if <emphasis>BX_USE_SOUND_VIRTUAL</emphasis>
is defined, just as in the examples.
The constructor should call the inherited constructor
as usual, even though the current constructor does not do
anything yet.
</para></listitem>
</itemizedlist>
</section>


<section><title>Methods</title>
<para>
The following are the methods that the output class has to override.
All but constructor and destructor have to return either
<emphasis>BX_SOUND_OUTPUT_OK</emphasis> <emphasis>(0)</emphasis> if the function was successful,
or <emphasis>BX_SOUND_OUTPUT_ERR</emphasis> <emphasis>(1)</emphasis> if not. If any of the initialization
functions fail, output to that device is disabled until the emulator is restarted.
</para>
</section>

<section><title>bx_sound_OS_c(bx_sb16_c*sb16)</title>

<para>
The emulator instantiates the class at the initialization of Bochs.
</para>

<para>
Description of the parameter:
</para>

<itemizedlist>
<listitem><para>
<emphasis>sb16</emphasis> is a pointer to the emulator class.
This pointer can then be used to access for example the <emphasis>writelog</emphasis> function to generate
sound-related log messages. Apart from that, no access to the emulator
should be necessary.
</para></listitem>

<listitem><para>
The constructor should <emphasis>not</emphasis> allocate the output devices.
This shouldn't be done until the actual output occurs; in either
<emphasis>initmidioutput()</emphasis> or <emphasis>initwaveoutput()</emphasis>.
Otherwise it would be impossible to have two copies of Bochs running
concurrently (if anybody ever wants to do this).
</para></listitem>
</itemizedlist>
</section>

<section><title>~bx_sound_OS_c()</title>

<para>
The instance is destroyed just before Bochs ends.
</para>
</section>

<section><title>int openmidioutput(char *device)</title>

<itemizedlist>
<listitem><para>
<emphasis>openmidioutput()</emphasis> is called when the first midi output starts.
It is only called if the midi output mode is 1 (midimode 1). It should
prepare the given MIDI hardware for receiving midi commands.
</para></listitem>

<listitem><para>
<emphasis>openmidioutput()</emphasis> will always be called before <emphasis>openwaveoutput()</emphasis>,
and <emphasis>closemidioutput()</emphasis>will always be called before <emphasis>closewaveoutput()</emphasis>, but not in all cases will both functions be called.
</para></listitem>
</itemizedlist>
</section>

<section>
<title>Description of the parameters:</title>

<itemizedlist>

<listitem><para>
<emphasis>device</emphasis> is a system-dependent variable.
It contains the value of the <emphasis>MIDI=device</emphasis> configuration option.
</para></listitem>

<listitem><para>
Note that only one midi output device will be used at any one time.
<emphasis>device</emphasis>
may not have the same value throughout one session, but it will be closed
before it is changed.
</para></listitem>
</itemizedlist>
</section>

<section><title>int midiready()</title>

<para>
<emphasis>midiready()</emphasis> is called whenever the applications asks if the
midi queue can accept more data.
</para>

<para>
Return values:
</para>

<itemizedlist>
<listitem><para>
<emphasis>BX_SOUND_OUTPUT_OK</emphasis> if the midi output device is ready.
</para></listitem>

<listitem><para>
<emphasis>BX_SOUND_OUTPUT_ERR</emphasis> if it isn't ready.
</para></listitem>
</itemizedlist>

<para>
<emphasis>Note: </emphasis><emphasis>midiready()</emphasis> will be called a few times
<emphasis>before</emphasis> the device is opened. If this is the case, it should
always report that it is ready, otherwise the application (not Bochs)
will hang.
</para>
</section>

<section><title>int sendmidicommand(int delta, int command, int length, Bit8u data[])</title>

<para>
<emphasis>sendmidicommand()</emphasis>is called whenever a complete midi command has
been written to the emulator. It should then send the given midi command to the midi hardware.
It will only be called after the midi output has been opened. Note that
if at all possible it should not wait for the completion of the command
and instead indicate that the device is not ready during the execution
of the command. This is to avoid delays in the program while it is
generating midi output.
</para>

<para>
Description of the parameters:
</para>

<itemizedlist>
<listitem><para>
<emphasis>delta</emphasis> is the number of delta ticks that
have passed since the last command has been issued. It is always zero for
the first command. There are 24 delta ticks per quarter, and 120 quarters
per minute, thus 48 delta ticks per second.
</para></listitem>

<listitem><para>
<emphasis>command</emphasis> is the midi command byte (sometimes
called status byte), in the usual range of 0x80..0xff. For more information
please see the midi standard specification.
</para></listitem>

<listitem><para>
<emphasis>length</emphasis> is the number of data bytes that
are contained in the data structure. This does <emphasis>not</emphasis> include the status
byte which is not replicated in the data array. It can only be greater
than 3 for SysEx messages (commands <emphasis>0xF0</emphasis> and <emphasis>0xF7</emphasis>)
</para></listitem>

<listitem><para>
<emphasis>data[]</emphasis> is the array of these data bytes,
in the order they have in the standard MIDI specification.
Note, it might be <emphasis>NULL</emphasis> if length==0.
</para></listitem>
</itemizedlist>
</section>


<section><title>int closemidioutput()</title>

<para>
<emphasis>closemidioutput()</emphasis> is called before shutting down Bochs or
when the
emulator gets the <emphasis>stop_output</emphasis> command through the emulator port.
After this, no more output will be necessary until <emphasis>openmidioutput()</emphasis>
is called again, but <emphasis>midiready()</emphasis> might still be called. It should do the following:
</para>

<itemizedlist>
<listitem><para>
Wait for all remaining messages to be completed
</para></listitem>
<listitem><para>
Reset and close the midi output device
</para></listitem>
</itemizedlist>
</section>


<section><title>int openwaveoutput(char *device)</title>

<para>
<emphasis>openwaveoutput()</emphasis> is called when the first wave output occurs,
and only if the selected wavemode is 1. It should do the following:
</para>

<itemizedlist>
<listitem><para>
Open the given device, and prepare it for wave output
</para></listitem>
</itemizedlist>
<para>
<emphasis>or</emphasis>
</para>
<itemizedlist>
<listitem><para>
Store the device name so that the device can be opened in <emphasis>startplayback()</emphasis>.
</para></listitem>
</itemizedlist>

<para>
<emphasis>openmidioutput()</emphasis> will always be called before <emphasis>openwaveoutput()</emphasis>,
and <emphasis>closemidioutput()</emphasis>will always be called before <emphasis>closewaveoutput()</emphasis>, but not in all cases will both functions be called.
</para>

<para>
<emphasis>openwaveoutput()</emphasis> will typically be called once, whereas
<emphasis>startplayback()</emphasis> is called for every new DMA transfer to the SB16 emulation. If feasible,
it could be useful to open and/or lock the output device in
<emphasis>startplayback()</emphasis> as opposed to <emphasis>openwaveoutput()</emphasis>
to ensure that it can be used by other applications while Bochs doesn't
need it.
</para>

<para>
However, many older applications don't use the auto-init DMA
mode, which means that they start a new DMA transfer for every single
block of output, which means usually for every 2048 bytes or so.
Unfortunately there is no way of knowing whether the application will
restart an expired DMA transfer soon, so that in these cases the
<emphasis>startwaveplayback</emphasis> function will be called very often, and it
isn't a good idea to have it reopen the device every time.
</para>

<para>The buffer when writing to the device should not be overly large.
Usually about four buffers of 4096 bytes produce best results. Smaller
buffers could mean too much overhead, while larger buffers contribute
to the fact that the actual output will always be late when the application
tries to synchronize it with for example graphics.
</para>

<para>The parameters are the following: </para>

<itemizedlist>
<listitem><para>
<emphasis>device</emphasis> is the wave device selected by
the user. It is strictly system-dependent. The value is that of the
<emphasis>WAVE=device</emphasis>
configuration option.
</para></listitem>
</itemizedlist>

<para>
Note that only one wave output device will be used at any one time.
<emphasis>device</emphasis> may not have the same value throughout one session, but it will be closed
before it is changed.
</para>
</section>

<section>
<title>int startwaveplayback(int frequency, int bits, int stereo, int format)</title>

<para>
This function is called whenever the application starts a new DMA transfer.  It should do the following:
</para>

<itemizedlist>
<listitem><para>
Open the wave output device, unless <emphasis>openwaveoutput()</emphasis> did that
already
</para></listitem>

<listitem><para>
Prepare the device for data and set the device parameters to those given
in the function call
</para></listitem>
</itemizedlist>

<para>
The parameters are the following:
</para>

<itemizedlist>
<listitem><para>
<emphasis>frequency</emphasis> is the desired frequency of the
output. Because of the capabities of the SB16, it can have any value between
5000 and 44,100.
</para></listitem>

<listitem><para>
<emphasis>bits</emphasis> is either 8 or 16, denoting the resolution
of one sample.
</para></listitem>

<listitem><para>
<emphasis>stereo</emphasis> is either 1 for stereo output, or 0 for mono output.
</para></listitem>

<listitem><para>
<emphasis>format</emphasis> is a bit-coded value (see below).
</para></listitem>
</itemizedlist>

<para>
<table>
<title>format bits</title>
<tgroup cols="2">
<thead>
<row>
<entry>Bit number</entry>
<entry>Meaning</entry>
</row>
</thead>
<tbody>
<row> <entry> 0 (LSB)  </entry><entry><para> 0: unsigned data </para><para>
                                            1: signed data </para></entry> </row>
<row> <entry> 1..6     </entry><entry> Type of codec (see below) </entry> </row>
<row> <entry> 7        </entry><entry><para> 0: no reference byte </para><para>
                                             1: with reference byte </para></entry> </row>
<row> <entry> 8..x     </entry><entry> reserved (0) </entry> </row>
</tbody>
</tgroup>
</table>

<table>
<title>codecs</title>
<tgroup cols="2">
<thead>
<row>
<entry>Value</entry>
<entry>Meaning</entry>
</row>
</thead>
<tbody>
<row> <entry> 0 </entry><entry> PCM (raw data) </entry> </row>
<row> <entry> 1 </entry><entry> reserved </entry> </row>
<row> <entry> 2 </entry><entry> 2-bit ADPCM (Creative Labs format) </entry> </row>
<row> <entry> 3 </entry><entry> 2.4-bit (3-bit) ADPCM (Creative Labs format) </entry> </row>
<row> <entry> 4 </entry><entry> 4-bit ADPCM (Creative Labs format) </entry> </row>
</tbody>
</tgroup>
</table>
</para>
<para>
Other codecs are not supported by the SB hardware. In fact, most applications will
translate their data into raw data, so that in most cases the codec will be zero.
</para>
<para>
The number of bytes per sample can be calculated from this as (bits / 8) * (stereo + 1).
</para>
</section>


<section>
<title>int waveready()</title>

<para>
This is called whenever the emulator has another output buffer ready
and would like to pass it to the output class. This happens every
<emphasis>BX_SOUND_OUTPUT_WAVEPACKETSIZE</emphasis> bytes, or whenever a DMA transfer
is done or aborted.
</para>

<para>
It should return whether the output device is ready for another buffer
of <emphasis>BX_SOUND_OUTPUT_WAVEPACKETSIZE</emphasis> bytes.
If <emphasis>BX_SOUND_OUTPUT_ERR</emphasis>
is returned, the emulator waits about 1/(frequency * bytes per sample) seconds
and then asks again. The DMA transfer is stalled during that time, but
the application keeps running, until the output device becomes ready.
</para>

<para>
As opposed to <emphasis>midiready(), waveready()</emphasis> will <emphasis>not</emphasis> be
called unless the device is open.
</para>
</section>

<section>
<title>int sendwavepacket(int length, Bit8u data[])</title>

<para>
This function is called whenever a data packet of at most <emphasis>BX_SB16_WAVEPACKETSIZE</emphasis>
is ready at the SB16 emulator. It should then do the following:
</para>

<itemizedlist>
<listitem><para>
Send this wave packet to the wave hardware
</para></listitem>
</itemizedlist>

<para>
This function <emphasis>has</emphasis> to be synchronous, meaning that it <emphasis>has</emphasis>
to return immediately, and <emphasis>not</emphasis> wait until the output is done. Also,
this function might be called before the previous output is done. If your
hardware can't append the new output to the old one, you will have to implement
this yourself, or the output will be very chunky, with as much silence
between the blocks as the blocks take to play. This is not what you want.
Instead, <emphasis>waveready()</emphasis> should return <emphasis>BX_SOUND_OUTPUT_ERR</emphasis>
until the device accepts another block of data.
</para>

<para>
Parameters:
</para>

<itemizedlist>
<listitem><para>
<emphasis>length</emphasis> is the number of data bytes in
the data stream. It will never be larger than <emphasis>BX_SB16_WAVEPACKETSIZE</emphasis>.
</para></listitem>

<listitem><para>
<emphasis>data</emphasis> is the array of data bytes.
</para></listitem>
</itemizedlist>

<para>
The order of bytes in the data stream is the same as that in the Wave file format:

<table>
<title>wave output types</title>
<tgroup cols="2">
<thead>
<row>
<entry>Output type</entry>
<entry>Sequence of data bytes</entry>
</row>
</thead>
<tbody>
<row> <entry> 8 bit mono </entry><entry> Sample 1; Sample 2; Sample 3; etc. </entry> </row>
<row> <entry> 8 bit stereo </entry><entry> Sample 1, Channel 0; Sample 1, Channel 1; Sample 2, Channel 0; Sample 2, Channel 1; etc. </entry> </row>
<row> <entry> 16 bit mono </entry><entry> Sample 1, LSB; Sample 1, MSB; Sample 2, LSB; Sample 2, MSB; etc. </entry> </row>
<row> <entry> 16 bit stereo </entry><entry> Sample 1, LSB, Channel 0; Sample 1, MSB, Channel 0; Sample 1, LSB, Channel 1; Sample 1, MSB, Channel 1; etc. </entry> </row>
</tbody>
</tgroup>
</table>
</para>

<para>
Typically 8 bit data will be unsigned with values from 0 to 255, and
16 bit data will be signed with values from -32768 to 32767, although the
SB16 is not limited to this. For further information on the codecs and
the use of reference bytes please refer to the Creative Labs Sound Blaster
Programmer's Manual, which can be downloaded from the Creative Labs web
site.
</para>
</section>

<section><title>int stopwaveplayback()</title>

<para>
This function is called at the end of a DMA transfer. It should do the following:
</para>

<itemizedlist>
<listitem><para>
Close the output device if it was opened by <emphasis>startwaveplayback()</emphasis>.
and it's not going to be opened soon. Which is almost impossible to tell.
</para></listitem>
</itemizedlist>
</section>

<section><title>int closewaveoutput()</title>

<para>
This function is called just before Bochs exits. It should do the following:
</para>

<itemizedlist>
<listitem><para>
 Close the output device, if this hasn't been done by <emphasis>stopwaveplayback()</emphasis>.
</para></listitem>
</itemizedlist>

<para>
Typically, <emphasis>stopwaveplayback()</emphasis> will be called several times, whenever
a DMA transfer is done, where <emphasis>closewaveoutput()</emphasis> will only be called
once. However, in the future it might be possible that <emphasis>openwaveoutput()</emphasis>
is called again, for example if the user chose to switch devices while
Bochs was running. This is not supported at the moment, but might be in
the future.
</para>
</section>

</section> <!-- end of SB16 section-->

<section id="harddisk-redologs"><title>Harddisk Images based on redologs</title>
<para>
This section describes how the three new disk images "undoable", "growing", and "volatile" are
implemented in Bochs 2.1. It also applies to the write support the "vvfat" disk
image mode in Bochs 2.4.6.
</para>
<itemizedlist>
<listitem><para>
undoable -> flat file, plus growing, commitable, rollbackable redolog file
</para></listitem>
<listitem><para>
growing  -> growing files, all previously unwritten sectors go to the end of file
</para></listitem>
<listitem><para>
volatile -> flat file, plus hidden growing redolog
</para></listitem>
<listitem><para>
vvfat -> virtual VFAT disk created from directory, plus hidden growing redolog
</para></listitem>
</itemizedlist>

<para>
</para>

<section>
<title>
        Description
</title>
<para>
The idea behind volatile and undoable disk images
is to have a flat file, associated with one redolog file.
In case of vvfat, a directory is associated with the redolog file.
</para>
<para>
Reading a sector is done from the redolog file if it contains
the sector, or from the flat file / vvfat directory otherwise.
</para>
<para>
Sectors written go to the redolog,
so flat files are opened in read only mode in this configuration.
</para>
<para>
The redolog is designed in a way so it starts as a small file
and grows with every new sectors written to it. Previously written
sectors are done in place. Redolog files can not shrink.
</para>
<para>
The redolog is a growing file that can be created on the fly.
</para>
<para>
Now, it turns out that if you only use a redolog without any
flat file, you get a "growing" disk image.
</para>
<para>
So "undoable", "volatile", "growing" and "vvfat" harddisk images classes
are implemented on top of a redolog class.
</para>
</section>

<section>
<title>
        How redologs works ?
</title>

<para>
At the start of a redolog file, there is a header, so Bochs can check whether
a file is consistent.
This header could also be checked when we implement
automatic type and size detection.
</para>
<para>
The generic part of the header contains values like type of image, and
spec version number.
</para>
<para>
The header also has a specific part.
For redologs, the number
of entries of the catalog, the extent, bitmap and disk size are stored.
</para>

<para>
In a redolog, the disk image is divided in a number of equal size "extents".
Each extent is a collection of successive 512-bytes sectors of the disk image,
preceeded by a n*512bytes bitmap.
</para>

<para>
the n*512bytes bitmap defines the presence (data has been written to it)
of a specific sector in the extent, one bit for each sector.
Therefore with a 512bytes bitmap, each extent can hold up to 4k blocks
</para>

<para>
Typically the catalog can have 256k entries.
With a 256k entries catalog and 512bytes bitmaps, the redolog can hold up to 512GiB
</para>

<note>
<para>
All data is stored on images as little-endian values
</para>
</note>
<section>
<title>
        Header
</title>
<para>
At the start of a redolog file, there is a header. This header is designed
to be reusable by other disk image types.
</para>
<para>
The header length is 512 bytes. It contains :
<table>
<title>Generic header description</title>
<tgroup cols="5">
<thead>
<row>
<entry>Start position in bytes</entry>
<entry>Length in bytes</entry>
<entry>Data type</entry>
<entry>Description</entry>
<entry>Possible values</entry>
</row>
</thead>
<tbody>
<row> <entry> 0 </entry> <entry> 32 </entry> <entry> string </entry> <entry> magical value </entry> <entry> Bochs Virtual HD Image </entry> </row>
<row> <entry> 32 </entry> <entry> 16 </entry> <entry> string </entry> <entry> type of file </entry> <entry> Redolog </entry> </row>
<row> <entry> 48 </entry> <entry> 16 </entry> <entry> string </entry> <entry> subtype of file </entry> <entry> Undoable, Volatile, Growing </entry> </row>
<row> <entry> 64 </entry> <entry> 4 </entry> <entry> Bit32u </entry> <entry> version of used specification </entry> <entry> 0x00010000 </entry> </row>
<row> <entry> 68 </entry> <entry> 4 </entry> <entry> Bit32u </entry> <entry> header size </entry> <entry> 512 </entry> </row>
</tbody>
</tgroup>
</table>
<table>
<title>Redolog specific header description</title>
<tgroup cols="5">
<thead>
<row>
<entry>Start position in bytes</entry>
<entry>Length in bytes</entry>
<entry>Data type</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row> <entry> 72 </entry> <entry> 4 </entry> <entry> Bit32u </entry> <entry> number of entries in the catalog </entry> </row>
<row> <entry> 76 </entry> <entry> 4 </entry> <entry> Bit32u </entry> <entry> bitmap size in bytes </entry> </row>
<row> <entry> 80 </entry> <entry> 4 </entry> <entry> Bit32u </entry> <entry> extent size in bytes</entry> </row>
<row> <entry> 84 </entry> <entry> 8 </entry> <entry> Bit64u </entry> <entry> disk size in bytes </entry> </row>
</tbody>
</tgroup>
</table>
</para>
</section>
<section>
<title>
        Catalog
</title>
<para>
Immediately following the header, there is a catalog containing
the position number (in extents) where each extent is located in the file.
</para>
<para>
Each position is a Bit32u entity.
</para>

</section>
<section>
<title>
        Extent
</title>
<para>
	 &FIXME;
</para>
</section>
</section>

<section>
<title>Parameters
</title>
<para>
The following tables shows what parameters are used when creating redologs or creating "growing" images :
<table>
<title>
        How number of entries in the catalog and number of blocks by extents are computed
</title>
<tgroup cols="5">
<thead>
<row>
<entry>Catalog entries</entry> <entry>Catalog size(KiB)</entry> <entry>Bitmap size (B)</entry> <entry>Extent size (KiB)</entry> <entry>Disk Max Size</entry>
</row>
</thead>

<tbody>
<row>
<entry>512</entry> <entry>2</entry> <entry>1</entry> <entry>4</entry> <entry>2MiB</entry>
</row>
<row>
<entry>512</entry> <entry>2</entry> <entry>2</entry> <entry>8</entry> <entry>4MiB</entry>
</row>
<row>
<entry>1k</entry> <entry>4</entry> <entry>2</entry> <entry>8</entry> <entry>8MiB</entry>
</row>
<row>
<entry>1k</entry> <entry>4</entry> <entry>4</entry> <entry>16</entry> <entry>16MiB</entry>
</row>
<row>
<entry>2k</entry> <entry>8</entry> <entry>4</entry> <entry>16</entry> <entry>32MiB</entry>
</row>
<row>
<entry>2k</entry> <entry>8</entry> <entry>8</entry> <entry>32</entry> <entry>64MiB</entry>
</row>
<row>
<entry>4k</entry> <entry>16</entry> <entry>8</entry> <entry>32</entry> <entry>128MiB</entry>
</row>
<row>
<entry>4k</entry> <entry>16</entry> <entry>16</entry> <entry>64</entry> <entry>256MiB</entry>
</row>
<row>
<entry>8k</entry> <entry>32</entry> <entry>16</entry> <entry>64</entry> <entry>512MiB</entry>
</row>
<row>
<entry>8k</entry> <entry>32</entry> <entry>32</entry> <entry>128</entry> <entry>1GiB</entry>
</row>
<row>
<entry>16k</entry> <entry>64</entry> <entry>32</entry> <entry>128</entry> <entry>2GiB</entry>
</row>
<row>
<entry>16k</entry> <entry>64</entry> <entry>64</entry> <entry>256</entry> <entry>4GiB</entry>
</row>
<row>
<entry>32k</entry> <entry>128</entry> <entry>64</entry> <entry>256</entry> <entry>8GiB</entry>
</row>
<row>
<entry>32k</entry> <entry>128</entry> <entry>128</entry> <entry>512</entry> <entry>16GiB</entry>
</row>
<row>
<entry>64k</entry> <entry>256</entry> <entry>128</entry> <entry>512</entry> <entry>32GiB</entry>
</row>
<row>
<entry>64k</entry> <entry>256</entry> <entry>256</entry> <entry>1024</entry> <entry>64GiB</entry>
</row>
<row>
<entry>128k</entry> <entry>512</entry> <entry>256</entry> <entry>1024</entry> <entry>128GiB</entry>
</row>
<row>
<entry>128k</entry> <entry>512</entry> <entry>512</entry> <entry>2048</entry> <entry>256GiB</entry>
</row>
<row>
<entry>256k</entry> <entry>1024</entry> <entry>512</entry> <entry>2048</entry> <entry>512GiB</entry>
</row>
<row>
<entry>256k</entry> <entry>1024</entry> <entry>1024</entry> <entry>4096</entry> <entry>1TiB</entry>
</row>
<row>
<entry>512k</entry> <entry>2048</entry> <entry>1024</entry> <entry>4096</entry> <entry>2TiB</entry>
</row>
<row>
<entry>512k</entry> <entry>2048</entry> <entry>2048</entry> <entry>8192</entry> <entry>4TiB</entry>
</row>
<row>
<entry>1024k</entry> <entry>4096</entry> <entry>2048</entry> <entry>8192</entry> <entry>8TiB</entry>
</row>
<row>
<entry>1024k</entry> <entry>4096</entry> <entry>4096</entry> <entry>16384</entry> <entry>16TiB</entry>
</row>
<row>
<entry>2048k</entry> <entry>8192</entry> <entry>4096</entry> <entry>16384</entry> <entry>32TiB</entry>
</row>
</tbody>
</tgroup>
</table>
</para>

</section>

<section>
<title>
        Redolog class description
</title>
<para>
The class <emphasis>redolog_t();</emphasis> implements the necessary
methods to create, open, close, read and write data to a redolog.
Managment of header catalog and sector bitmaps is done internally
by the class.
</para>
<section>
<title>
        Constants
</title>
<para>
<screen>
#define STANDARD_HEADER_MAGIC     "Bochs Virtual HD Image"
#define STANDARD_HEADER_VERSION   (0x00010000)
#define STANDARD_HEADER_SIZE      (512)
</screen>
These constants are used in the generic part of the header.
</para>

<para>
<screen>
#define REDOLOG_TYPE "Redolog"
#define REDOLOG_SUBTYPE_UNDOABLE "Undoable"
#define REDOLOG_SUBTYPE_VOLATILE "Volatile"
#define REDOLOG_SUBTYPE_GROWING  "Growing"
</screen>
These constants are used in the specific part of the header.
</para>

<para>
<screen>
#define REDOLOG_PAGE_NOT_ALLOCATED (0xffffffff)
</screen>
This constant is used in the catalog for an unwritten extent.
</para>

</section> <!-- Constants -->

<section> <title>Methods</title>
<para>
<emphasis>redolog_t();</emphasis> instanciates a new redolog.
</para>
<para>
<emphasis>int make_header (const char* type, Bit64u size);</emphasis> creates a header
structure in memory, and sets its <emphasis>type</emphasis> and parameters based on the
disk image <emphasis>size</emphasis>. Returns 0.
</para>
<para>
<emphasis>int create (const char* filename, const char* type, Bit64u size);</emphasis>
creates a new empty redolog file, with header and catalog, named <emphasis>filename</emphasis>
of type <emphasis>type</emphasis> for a <emphasis>size</emphasis> bytes image.
Returns 0 for OK or -1 if a problem occured.
</para>
<para>
<emphasis>int create (int filedes, const char* type, Bit64u size);</emphasis>
creates a new empty redolog file, with header and catalog, in a previously
opened file described by <emphasis>filedes</emphasis>, of type <emphasis>type</emphasis>
for a <emphasis>size</emphasis> bytes image.
Returns 0 for OK or -1 if a problem occured.
</para>
<para>
<emphasis>int open (const char* filename, const char* type, Bit64u size);</emphasis>
opens a redolog file named <emphasis>filename</emphasis>, and checks
for consistency of header values against a <emphasis>type</emphasis> and
<emphasis>size</emphasis>.
Returns 0 for OK or -1 if a problem occured.
</para>
<para>
<emphasis>void close ();</emphasis>
closes a redolog file.
</para>
<para>
<emphasis>off_t lseek (off_t offset, int whence);</emphasis>
seeks at logical data offset <emphasis>offset</emphasis> in a redolog.
<emphasis>offset</emphasis> must be a multiple of 512.
Only SEEK_SET is supported for <emphasis>whence</emphasis>.
Returns -1 if a problem occured, or the current logical offset in
the redolog.
</para>
<para>
<emphasis>ssize_t read (void* buf, size_t count);</emphasis>
reads <emphasis>count</emphasis> bytes of data of the redolog, from current logical offset,
and copies it into <emphasis>buf</emphasis>.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes read, that can be 0 if the data
has not previously be written to the redolog.
</para>
<para>
<emphasis>ssize_t write (const void* buf, size_t count);</emphasis>
writes <emphasis>count</emphasis> bytes of data from <emphasis>buf</emphasis>
to the redolog, at current logical offset.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes written.
</para>

</section>

</section> <!-- Redolog class description -->

<section>
<title>
        Disk image classes description
</title>
<para>
"volatile" and "undoable" disk images are easily implemented
by instanciating a <emphasis>default_image_t</emphasis> object (flat image)
and a <emphasis>redolog_t</emphasis> object (redolog).
</para>
<para>
"growing" disk images only instanciates a <emphasis>redolog_t</emphasis> object.
</para>
<para>
Classe names are <emphasis>undoable_image_t</emphasis>, <emphasis>volatile_image_t</emphasis>
and <emphasis>growing_image_t</emphasis>.
</para>
<para>
When using these disk images, the underlying data structure and layout
is completely
hidden to the caller. Then, all offset and size values are "logical" values,
as if the disk was a flat file.
</para>
<section>
<title>
        Constants
</title>
<para>
<screen>
#define UNDOABLE_REDOLOG_EXTENSION ".redolog"
#define UNDOABLE_REDOLOG_EXTENSION_LENGTH (strlen(UNDOABLE_REDOLOG_EXTENSION))
#define VOLATILE_REDOLOG_EXTENSION ".XXXXXX"
#define VOLATILE_REDOLOG_EXTENSION_LENGTH (strlen(VOLATILE_REDOLOG_EXTENSION))
</screen>
These constants are used when building redolog file names
</para>
</section>

<section>
<title>
        undoable_image_t methods
</title>
<para>
<emphasis>
undoable_image_t(Bit64u size, const char* redolog_name);
</emphasis>
instanciates a new <emphasis>undoable_image_t</emphasis>
object. This disk image logical length is <emphasis>size</emphasis> bytes and
the redolog filename is <emphasis>redolog_name</emphasis>.
</para>

<para>
<emphasis>
int open (const char* pathname);
</emphasis>
opens the flat disk image <emphasis>pathname</emphasis>,
as an undoable disk image. The associated redolog will
be named <emphasis>pathname</emphasis> with a
<emphasis>UNDOABLE_REDOLOG_EXTENSION</emphasis>
suffix, unless set in the constructor.
Returns 0 for OK or -1 if a problem occured.
</para>

<para>
<emphasis>
void close ();
</emphasis>
closes the flat image and its redolog.
</para>

<para>
<emphasis>
off_t lseek (off_t offset, int whence);
</emphasis>
seeks at logical data position <emphasis>offset</emphasis> in
the undoable disk image.
Only SEEK_SET is supported for <emphasis>whence</emphasis>.
Returns -1 if a problem occured, or the current logical
offset in the undoable disk image.
</para>

<para>
<emphasis>
ssize_t read (void* buf, size_t count);
</emphasis>
reads <emphasis>count</emphasis> bytes of data
from the undoable disk image, from current logical offset,
and copies it into <emphasis>buf</emphasis>.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes read.
Data will be read from the redolog if it has
been previously written or from the flat image
otherwise.
</para>

<para>
<emphasis>
ssize_t write (const void* buf, size_t count);
</emphasis>
writes <emphasis>count</emphasis> bytes of data from <emphasis>buf</emphasis>
to the undoable disk image, at current logical offset.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes written.
Data will always be written to the redolog.
</para>
</section>

<section>
<title>
        volatile_image_t methods
</title>
<para>
<emphasis>
volatile_image_t(Bit64u size, const char* redolog_name);
</emphasis>
instanciates a new <emphasis>volatile_image_t</emphasis>
object. This disk image logical length is <emphasis>size</emphasis> bytes and
the redolog filename is <emphasis>redolog_name</emphasis> plus a
random suffix.
</para>

<para>
<emphasis>
int open (const char* pathname);
</emphasis>
opens the flat disk image <emphasis>pathname</emphasis>,
as a volatile disk image. The associated redolog will
be named <emphasis>pathname</emphasis> with a
random suffix, unless set in the constructor.
Returns 0 for OK or -1 if a problem occured.
</para>

<para>
<emphasis>
void close ();
</emphasis>
closes the flat image and its redolog.
The redolog is deleted/lost after close is called.
</para>

<para>
<emphasis>
off_t lseek (off_t offset, int whence);
</emphasis>
seeks at logical data position <emphasis>offset</emphasis> in
the volatile disk image.
Only SEEK_SET is supported for <emphasis>whence</emphasis>.
Returns -1 if a problem occured, or the current logical offset in
the volatile disk image.
</para>

<para>
<emphasis>
ssize_t read (void* buf, size_t count);
</emphasis>
reads <emphasis>count</emphasis> bytes of data
from the volatile disk image, from current logical offset,
and copies it into <emphasis>buf</emphasis>.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes read.
Data will be read from the redolog if it has
been previously written or from the flat image
otherwise.
</para>

<para>
<emphasis>
ssize_t write (const void* buf, size_t count);
</emphasis>
writes <emphasis>count</emphasis> bytes of data from <emphasis>buf</emphasis>
to the volatile disk image, at current logical offset.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes written.
Data will always be written to the redolog.
</para>
</section>

<section>
<title>
        growing_image_t methods
</title>
<para>
<emphasis>
growing_image_t(Bit64u size);
</emphasis>
instanciates a new <emphasis>growing_image_t</emphasis>
object. This disk image logical length is <emphasis>size</emphasis> bytes.
</para>

<para>
<emphasis>
int open (const char* pathname);
</emphasis>
opens the growing disk image <emphasis>pathname</emphasis>,
Returns 0 for OK or -1 if a problem occured.
</para>

<para>
<emphasis>
void close ();
</emphasis>
closes the growing disk image.
</para>

<para>
<emphasis>
off_t lseek (off_t offset, int whence);
</emphasis>
seeks at logical data position <emphasis>offset</emphasis> in
the growable disk image.
Only SEEK_SET is supported for <emphasis>whence</emphasis>.
Returns -1 if a problem occured, or the current logical offset in
the grwoing image.
</para>

<para>
<emphasis>
ssize_t read (void* buf, size_t count);
</emphasis>
reads <emphasis>count</emphasis> bytes of data
from the growing disk image, from current logical offset,
and copies it into <emphasis>buf</emphasis>.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes read.
The buffer will be filled with null bytes if data
has not been previously written to the growing image.
</para>

<para>
<emphasis>
ssize_t write (const void* buf, size_t count);
</emphasis>
writes <emphasis>count</emphasis> bytes of data from <emphasis>buf</emphasis>
to the growing disk image, at current logical offset.
<emphasis>count</emphasis> must be 512.
Returns the number of bytes written.
</para>
</section>

</section>

</section>

<section id="add-keymapping"><title>How to add keymapping in a GUI client</title>
<para>
Christophe Bothamy, wrote the keymapping code for Bochs, provided these
instructions to help developers to add keymapping to a GUI.
</para>

<screen>
Bochs creates a bx_keymap_c object named bx_keymap.
This object allows you to :
  - load the configuration specified keymap file
  - get the translated BX_KEY_* from your GUI key

You have to provide a translation function from string to your Bit32u key
constant. Casting will be necessary if your key constants are not Bit32u typed.
The function must be "static Bit32u (*)(const char *)" typed, and must return
BX_KEYMAP_UNKNOWN if it can not translate the parameter string.

What you have to do is :
  - call once "void loadKeymap(Bit32u (*)(const char*))",
    providing your translation function, to load the keymap
  - call "Bit32u getBXKey(Bit32u)" that returns the BX_KEY_*
    constant, for each key you want to map.

The file gui/x.cc implements this architecture, so you can refer to it
as an example.
</screen>

</section>

</chapter>

<chapter id="debugger"><title>Debugger</title>
      <section><title>compile with debugger support</title>
      <para>
      &FIXME;
      </para>
      </section>
      <section id="debugger-get-started"><title>get started in debugger</title>
      <para>
      &FIXME;
      </para>
      </section>
      <section id="debugger-commands"><title>command reference</title>
      <para>
      &FIXME;
      </para>
      </section>
      <section id="debugger-techniques"><title>techniques</title>
      <para>
      &FIXME;
      </para>
      </section>
<section id="iodebug"><title>I/O Interface to Bochs Debugger</title>
<para>
This device was added by Dave Poirier (eks@void-core.2y.net).
</para>
<para>
Compiling Bochs with iodebug support
<screen>
./configure --enable-iodebug
make
</screen>
Other optional fields may be added to the ./configure line, see Bochs documentation for all the information.
</para>

<para>
<screen>
Using the I/O Interface to the debugger

port range:  0x8A00 - 0x8A01

Port 0x8A00 servers as command register. You can use it to enable the i/o interface,
change which data register is active, etc.

Port 0x8A01 is used as data register for the memory monitoring.
</screen>
</para>
<section><title>Commands supported by port 0x8A00</title>
<para>
<screen>

0x8A00

 Used to enable the device. Any I/O to the debug module before this command is sent
 is sent will simply be ignored.


0x8A01

 Selects register 0: Memory monitoring range start address (inclusive)


0x8A02

 Selects register 1: Memory monitoring range end address (exclusive)


0x8A80

 Enable address range memory monitoring as indicated by register 0 and 1 and
 clears both registers


0x8AE0 - Return to Debugger Prompt

 If the debugger is enabled (via --enable-debugger), sending 0x8AE0 to port 0x8A00
 after the device has been enabled will return the Bochs to the debugger prompt.
 Basically the same as doing CTRL+C.


0x8AE2 - Instruction Trace Disable

 If the debugger is enabled (via --enable-debugger), sending 0x8AE2 to port 0x8A00
 after the device has been enabled will disable instruction tracing


0x8AE3 - Instruction Trace Enable

 If the debugger is enabled (via --enable-debugger), sending 0x8AE3 to port 0x8A00
 after the device has been enabled will enable instruction tracing


0x8AE4 - Register Trace Disable

 If the debugger is enabled (via --enable-debugger), sending 0x8AE4 to port 0x8A00
 after the device has been enabled will disable register tracing.


0x8AE5 - Register Trace Enable

 If the debugger is enabled (via --enable-debugger), sending 0x8AE5 to port 0x8A00
 after the device has been enabled will enable register tracing. This currently
 output the value of all the registers for each instruction traced.
 Note: instruction tracing must be enabled to view the register tracing


0x8AFF

 Disable the I/O interface to the debugger and the memory monitoring functions.
</screen>
<note><para>all accesses must be done using word</para></note>
<note><para>reading this register will return 0x8A00 if currently activated, otherwise 0</para></note>
</para>
</section>
<section><title>Access to port 0x8A01 (write-only)</title>
<para>
All accesses to this port must be done using words. Writing to this port will shift
to the left by 16 the current value of the register and add the provided value to it.
<screen>
Sample:

reg0 = 0x01234567

out port: 0x8A01 data: 0xABCD

reg0 = 0x4567ABCD
</screen>
</para>
</section>
<section><title>Sample</title>
<para>
Enable memory monitoring on first page of text screen (0xb8000-0xb8fa0):
add in bochrc file: <command>optromimage1: file=&quot;asmio.rom&quot;, address=0xd0000</command>
<screen>
/*
 *      Make asmio ROM file:
 *      gcc -c asmio.S
 *      objcopy -O binary asmio.o asmio.rom
 */
        .text
        .global start
        .code16

/* ROM Header */
        .byte 0x55
        .byte 0xAA
        .byte 1                 /* 512 bytes long */

start:
/* Monitor memory access on first page of text screen */
        mov     $0x8A00,%dx     /* Enable iodebug (0x8A00->0x8A00) */
        mov     %dx,%ax
        out     %ax,%dx
        mov     $0x8A01,%ax     /* Select register 0 start addr (0x8A01->0x8A00) */
        out     %ax,%dx
        mov     $0x8A01,%dx     /* Write start addr 0xB8000 (high word first) */
        mov     $0xB,%ax
        out     %ax,%dx
        mov     $0x8000,%ax     /* Write start addr (low word) */
        out     %ax,%dx

        mov     $0x8A02,%ax     /* Select register 1 end addr (0x8A02->0x8A00) */
        mov     $0x8A00,%dx
        out     %ax,%dx
        mov     $0x8A01,%dx     /* Write end addr 0xB8FA0 (high word first) */
        mov     $0xB,%ax
        out     %ax,%dx
        mov     $0x8FA0,%ax     /* Write end addr (low word) */
        out     %ax,%dx

        mov     $0x8A00,%dx     /* Enable addr range memory monitoring (0x8A80->0x8A00) */
        mov     $0x8A80,%ax
        out     %ax,%dx

        mov     $0x8A00,%dx     /* Return to Bochs Debugger Prompt (0x8AE0->0x8A00) */
        mov     $0x8AE0,%ax
        out     %ax,%dx
        lret

        .byte 0x6b              /* Checksum (code dependent!, update it as needed) */
        .align 512              /* NOP follow */
</screen>
</para>
</section>
</section>
</chapter>

<chapter id="coding"><title>Coding</title>
<section><title>Coding guidelines</title>
<para>
<itemizedlist>
<listitem><para><command>Don't make use of any external C++ classes.</command></para>
<para>They are not offered on all platforms and this would make Bochs non-portable.
There is use of such classes in the optional debugger. I plan on removing this use.
</para></listitem>
<listitem><para><command>Don't use fancy C++ features.</command></para>
<para>Bochs is incredibly performance sensitive, and will be increasingly so as
more speed enhancements are added. There's a time and place for most everything
and this is not it. Some advanced features create overhead in the generated code
that you don't see. They also convolute the code, and sometimes occlude that is
really going on.
<itemizedlist>
<listitem><para>Don't use templates</para></listitem>
<listitem><para>Don't use virtual functions if not strictly required</para></listitem>
<listitem><para>Don't use C++ exceptions</para></listitem>
<listitem><para>Don't use overloading of any kind</para></listitem>
</itemizedlist></para></listitem>
<listitem><para><command>Use soft tabs.</command></para>
<para>At least when you submit code, convert all hard tabs to spaces.
There is no uniform way to handle tabs properly.</para></listitem>
<listitem><para><command>Please do compile with all warnings turned on.</command></para>
<para>It's really difficult to spot interesting warnings when a compile is littered
with non-interesting ones.</para></listitem>
<listitem><para><command>Don't use signed ints where unsigned will do.</command></para></listitem>
<listitem><para><command>Make sure that contributed code / patches are LGPL compatible.</command></para></listitem>
</itemizedlist>
</para>
</section>
      <section id="patches"><title>patches:</title>
      <para>
      &FIXME;
      how to make, where to submit, what happens then?
      </para>
      </section>
<section id="cvs-release"><title>Building a Bochs release</title>
<section><title>Preparing source files and CVS</title>
<para>
Update version number and strings in configure.in.
<screen>
VERSION="2.4"
VER_STRING="2.4"
REL_STRING="Build from CVS snapshot on June 7, 2009"
</screen>
In the README file you have to update version number and date. Add some
information about new features if necessary.
<screen>
Bochs x86 Pentium+ Emulator
Updated: Sat May 3 07:34:00 CEST 2009
Version: 2.4
</screen>
Check date, update/sumup info in CHANGES. Run autoconf to regenerate configure and check them in.
Create a CVS tag to mark which revision of each file was used in the release.
For prereleases I make a normal CVS tag like this:
<screen>
  cvs tag REL_2_4_pre1
</screen>
But for a real release, I make a CVS branch tag AND a normal tag.
<screen>
  cvs tag REL_2_4_BASE
  cvs tag -b REL_2_4
</screen>
The base tag marks where the branch split off of the main trunk.
This is very useful in maintaining the branch since you can do diffs
against it.
<screen>
   cvs diff -r REL_2_4_BASE -r HEAD
   cvs diff -r REL_2_4_BASE -r REL_2_4
   cvs upd -j REL_2_4_BASE -j HEAD file
   etc.
</screen>
The release and all bugfix releases after it are on the REL_2_4 branch.
When the release is actually finalized, you can do this:
<screen>
  cvs tag REL_2_4_FINAL
</screen>
Now you can start building packages based on the created release tag.
</para>
</section>

<section><title>Building the release on win32</title>
<para>
These instructions require cygwin and MSVC++.
</para>
<para>
In Cygwin:
<screen>
  sh .conf.win32-vcpp         # runs configure
  make win32_snap             # unzip workspace, make a win32 source ZIP
</screen>
Copy the source ZIP to a windows machine, if necessary.
</para>
<para>
Open up Visual C++ and load the workspace file Bochs.dsw.  Check
the Build:Set Active Project Configuration is set the way you want it.
For releases I use "Win32 Release".
</para>
<para>
To create "bochsdbg.exe" with Bochs debugger support, manually change two
lines in config.h to turn on the debugger.
<screen>
#define BX_DEBUGGER 1
#define BX_DISASM 1
</screen>
VC++ will rebuild Bochs with debugger and overwrite bochs.exe.  To avoid
trashing the non-debug version, move it out of the way while the debugger
version is being built.  Then rename the debugger version to bochsdbg.exe.
<screen>
cd obj-release
mv bochs.exe bochs-normal.exe
(build again with BX_DEBUGGER=1 this time)
mv bochs.exe bochsdbg.exe
mv bochs-normal.exe bochs.exe
</screen>
</para>
<para>
To get the docbook installed, you need to do something like this:
<itemizedlist>
<listitem> <para> make dl_docbook </para> </listitem>
<listitem> <para> copy up to date doc files </para> </listitem>
</itemizedlist>
Then you can do
<screen>
cd doc/docbook; touch */*.html
</screen>
Do make install_win32 into /tmp or someplace:
<screen>
make install_win32 prefix=/tmp/bochs-2.4
</screen>
This copies all the files into /tmp/bochs-2.4 and then creates a
binary ZIP at /tmp/bochs-2.4.zip. Rename that bochs-2.4.win32-bin.zip.
</para>
<para>
Now make the NSIS installer package (the current script is known to work with NSIS 2.44)
<screen>
cd build/win32/nsis
</screen>
Unzip the binary ZIP file into bochs-$VERSION (must match Makefile) and
then run make.
<screen>
unzip ~/bochs-2.4.zip
make
</screen>
That gives an installer called <filename>Bochs-2.4.exe</filename>. Test and upload it.
</para>
</section>
<section><title>Building the release on Linux</title>
<para>
Do a clean checkout using anonymous cvs, so that the source tarball
will be all set up for anonymous cvs.  First I'll create a clean
directory called "clean-anon".
<screen>
cvs -d:pserver:anonymous@bochs.cvs.sourceforge.net:/cvsroot/bochs login
cvs -z3 -d:pserver:anonymous@bochs.cvs.sourceforge.net:/cvsroot/bochs \
  checkout -d clean-anon bochs
</screen>
Start with clean-anon which tracks the CVS head.  Change its sticky tag
so that it sticks to the release tag.
<screen>
cp -a clean-anon bochs-2.4
cd bochs-2.4
cvs upd -P -r REL_2_4_FINAL
cd ..
tar czvf bochs-2.4.tar.gz --exclude CVS --exclude .cvsignore bochs-2.4
</screen>
The source TAR file bochs-2.4.tar.gz is ready to upload.
</para>
<para>
The RPM will be building using the configuration in .conf.linux with
a few parameters from <command>build/redhat/make-rpm</command>.  Make any last minute changes
to .conf.linux.  Any changes will go into the source RPM. The DLX Linux demo package
will be downloaded to the Bochs root directory if it is not already present there.
<screen>
./build/redhat/make-rpm | tee ../build.txt
</screen>
This produces two rpm files in the current directory.  Test and upload.
</para>
</section>
<section><title>Creating a file release and uploading files on SF</title>
<para>
When you are ready with creating release packages you have to upload them using
the SF file manager feature. Create a subdirectory with the version number in
the <filename>bochs</filename> directory. Point the download destination to the
new directory and start uploading packages. The top of the <filename>CHANGES</filename>
file should be used as the release notes. After setting up the file properties the
new release is ready for download.
</para>
</section>

</section>

</chapter>

<chapter id="webmastering"><title>Webmastering</title>

<section id="project-webspace"><title>Bochs project webspace</title>
<para>
The Bochs project webspace is stored under the SF directory <filename>/home/project-web/bochs</filename>.
It can be accessed from the SF shell using SSH or with the commands <command>sftp</command>,
<command>scp</command> and <command>rsync</command>. Some parts of the directory
structure must be updated from the local CVS repository, others from Bochs CVS
(modules <filename>bochs</filename> and <filename>sfsite</filename>).
The online documentation, disk images and screenshots must be uploaded manually.
<table>
<title>Directory structure</title>
<tgroup cols="2">
<thead>
<row>
<entry>Location</entry>
<entry>Meaning</entry>
<entry>Update</entry>
</row>
</thead>
<tbody>
<row><entry>cgi-bin</entry><entry>CGI scripts for the website</entry></row>
<row><entry>htdocs</entry><entry>root directory of the website</entry></row>
<row><entry>htdocs/cvs-snapshot</entry><entry>link to current snapshot</entry></row>
<row><entry>htdocs/doc/docbook</entry><entry>Bochs online documentation</entry></row>
<row><entry>htdocs/docs-html</entry><entry>old Bochs documentation</entry></row>
<row><entry>htdocs/guestos</entry><entry>disk images directly stored on the Bochs website</entry></row>
<row><entry>htdocs/screenshot</entry><entry>screenshots of Bochs running several guest operating systems</entry></row>
<row><entry>htdocs/techspec</entry><entry>technical specifications of several hardware components</entry></row>
<row><entry>lxr</entry><entry>Bochs source browser</entry></row>
<row><entry>sfsite-cvsroot</entry><entry>local CVS repository</entry></row>
<row><entry>sitebin</entry><entry>shell scripts (e.g. for snapshot generation)</entry></row>
<row><entry>siteman</entry><entry>website manual pages</entry></row>
<row><entry>snapshot</entry><entry>CVS snapshot storage area</entry></row>
<row><entry>tmp</entry><entry>temp directory for shell scripts</entry></row>
</tbody>
</tgroup>
</table>
</para>
</section>

<section id="update-website"><title>Updating the Bochs website content</title>
<para>
The main HTML content of the Bochs website (except online documentation) is stored
in the <filename>sfsite</filename> module of the Bochs CVS repository. Unlike
other SF projects you don't need to upload these files to the Bochs project webspace.
Running a simple CVS update on the SF shell is enough after the files have been
updated in the repository. Please see <link linkend="cvs-write-access-setup">Setting
up CVS write access</link> for general instructions. The only difference is the
module name <filename>sfsite</filename> instead of <filename>bochs</filename>.
The example below shows how to start the SF shell with SSH and to update the
HTML files.
<screen>
ssh -t vruppert,bochs@shell.sourceforge.net create
vruppert,bochs@shell.sourceforge.net's password:

Requesting a new shell for "vruppert" and waiting for it to start.
queued... starting...

This is an interactive shell created for user vruppert,bochs.
Use the "timeleft" command to see how much time remains before shutdown.
Use the "shutdown" command to destroy the shell before the time limit.
For path information and login help, type "sf-help".

[vruppert@shell-24002 ~]$ cd /home/project-web/bochs/htdocs/
[vruppert@shell-24002 htdocs]$ cvs update
cvs update: Updating .
U index.html
cvs update: Updating images
cvs update: Updating includes
cvs update: Updating networking
cvs update: Updating testing-forms
cvs update: Updating docs-html
[vruppert@shell-24002 htdocs]$ shutdown
Requesting that your shell be shut down.
This request will be processed soon.
[vruppert@shell-24002 htdocs]$
Broadcast message from root (Sat Nov 15 08:36:01 2008):

The system is going down for system halt NOW!
Connection to shell-24002 closed by remote host.
Connection to shell-24002 closed.
Connection to shell.sourceforge.net closed.
</screen>
</para>
</section>

<section id="update-cvs-snapshot"><title>Updating the CVS snapshot</title>
<para>
The CVS snapshot
<footnote>
<para>The CVS snapshot link can be found on the bottom of the page
<filename>getcurrent.html</filename>.</para>
</footnote>
can be updated with SF shell access using SSH. There is a script
called <command>update-snapshots.sh</command> that can do all the required steps
(checking out CVS, packing the source tree into one archive, updating the website
link). See previous section how to create a shell.
<screen>
cd /home/project-web/bochs/sitebin/
./update-snapshots.sh
</screen>
</para>
</section>

<section id="update-online-docs"><title>Updating the online documentation</title>
<para>
To update the online documentation, a file called <filename>bochsdoc.tar.gz</filename>
must be generated with the <command>make</command>. This file must be uploaded
to the location of the online documentation on SF using <command>scp</command>.
<screen>
cd doc/docbook
make bochsdoc.tar.gz
scp bochsdoc.tar.gz vruppert,bochs@web.sf.net:htdocs/doc/docbook
</screen>
After a successful upload, the HTML files must be unpacked from the SF shell.
See section <link linkend="update-website">Updating the Bochs website content</link>
how to create a shell.
<screen>
cd /home/project-web/bochs/htdocs/doc/docbook
tar xvzf bochsdoc.tar.gz
</screen>
The updated files can be accessed from the sidebar of the Bochs website.
</para>
</section>

      <section id="other-content"><title>other content</title>
      <para>
      &FIXME; sources, tmp
      </para>
      </section>

      <section id="available-tools"><title>available tools</title>
      <para>
      &FIXME; sources, tmp
      </para>
      </section>

</chapter>
</book>
