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<b>Gavare's eXperimental Emulator:</b></font><br>
<font color="#000000" size="6"><b>Introduction</b>
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Copyright (C) 2003-2007  Anders Gavare.  All rights reserved.

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<a href="./">Back to the index</a>

<p><br>
<h2>Introduction</h2>

<p>
<table border="0" width="99%"><tr><td valign="top" align="left">
<ul>
  <li><a href="#overview">Overview</a>
  <li><a href="#free">Is GXemul Free software?</a>
  <li><a href="#build">How to compile/build the emulator</a>
  <li><a href="#run">How to run the emulator</a>
  <li><a href="#cpus">Which processor architectures does GXemul emulate?</a>
  <li><a href="#hosts">Which host architectures are supported?</a>
  <li><a href="#accuracy">Emulation accuracy</a>
  <li><a href="#emulmodes">Which machines does GXemul emulate?</a>
</ul>
</td><td valign="center" align="center">
<a href="20050317-example.png"><img src="20050317-example_small.png"></a>
<p>NetBSD/pmax 1.6.2 with X11<br>running in GXemul</td></tr></table>


<p><br>
<a name="overview"></a>
<h3>Overview:</h3>

GXemul is an experimental instruction-level machine emulator. Several
emulation modes are available. In some modes, processors and surrounding
hardware components are emulated well enough to let unmodified operating
systems (e.g. NetBSD) run as if they were running on a real machine.

<p>Devices and processors are not simulated with 100% accuracy. They are 
only ``faked'' well enough to allow guest operating systems to run without 
complaining too much. Still, the emulator could be of interest for 
academic research and experiments, such as when learning how to write 
operating system code.

<p>The emulator is written in C, does not depend on third-party libraries,
and should compile and run on most 64-bit and 32-bit Unix-like systems.

<p>The emulator contains code which tries to emulate the workings of CPUs
and surrounding hardware found in real machines, but it does not contain
any ROM code. You will need some form of program (in binary form) to run
in the emulator. For many emulation modes, PROM calls are handled by the
emulator itself, so you do not need to use any ROM image at all.

<p>You can use pre-compiled kernels (for example NetBSD kernels, or
Linux), or other programs that are in binary format, and in some cases
even actual ROM images. A couple of different file formats are supported
(ELF, a.out, ECOFF, SREC, and raw binaries).

<p>If you do not have a kernel as a separate file, but you have a bootable
disk image, then it is sometimes possible to boot directly from that
image. (This works for example with DECstation emulation, Dreamcast 
emulation, or when booting from generic ISO9660 CDROM images if the 
kernel is included in the image as a plain file.)

<p>Thanks to (in no specific order) Joachim Buss, Olivier Houchard, Juli 
Mallett, Juan Romero Pardines, Alec Voropay, Göran Weinholt, Alexander 
Yurchenko, and everyone else who has provided me with feedback.


<p><br>
<a name="free"></a>
<h3>Is GXemul Free software?</h3>

Yes. I have released GXemul under a Free license. The code in GXemul is
Copyrighted software, it is <i>not</i> public domain. (If this is
confusing to you, you might want to read up on the definitions of the
four freedoms associated with Free software, <a
href="http://www.gnu.org/philosophy/free-sw.html">http://www.gnu.org/philosophy/free-sw.html</a>.)

<p>The code I have written is released under a 3-clause BSD-style license
(or "revised BSD-style" if one wants to use <a
href="http://www.gnu.org/philosophy/bsd.html">GNU jargon</a>). Apart from
the code I have written, some files are copied from other sources such as
NetBSD, for example header files containing symbolic names of bitfields in
device registers. They are also covered by similar licenses, but with some
additional clauses. The main point, however, is that the licenses require
that the original Copyright and license terms are included when you make a
copy or modification.

<p>If you plan to redistribute GXemul <i>without</i> supplying the source
code, then you need to comply with each individual source file some other
way, for example by writing additional documentation containing copyright
notes. I have not done this, since I do not plan on making distributions
without source code. You need to check all individual files for details.
The "easiest way out" if you plan to redistribute code from GXemul is, of
course, to let it remain open source and simply supply the source code.

<p>In case you want to reuse parts of GXemul, but you need to do that 
under a different license (e.g. the GPL), then contact me and I might 
re-license/dual-license files on a case-by-case basis.


<p><br>
<a name="build"></a>
<h3>How to compile/build the emulator:</h3>

Uncompress the .tar.gz distribution file, and run
<pre>
        $ <b>./configure</b>
        $ <b>make</b>
</pre>

<p>This should work on most Unix-like systems. GXemul does not require any 
specific libraries to build, however, if you build on a system which does 
not have X11 libraries installed, some functionality will be lost.

<p>The emulator's performance is highly dependent on both runtime settings
and on compiler settings, so you might want to experiment with different
CC and CFLAGS environment variable values. For example, on an AMD Athlon
host, you might want to try setting <tt>CFLAGS</tt> to <tt>-march=athlon</tt>
before running <tt>configure</tt>.


<p><br>
<a name="run"></a>
<h3>How to run the emulator:</h3>

Once you have built GXemul, running it should be rather straight-forward.
Running <tt><b>gxemul</b></tt> without arguments (or with the
<b><tt>-h</tt></b> or <b><tt>-H</tt></b> command line options) will
display a help message.

<p>
To get some ideas about what is possible to run in the emulator, please 
read the section about <a href="guestoses.html">installing "guest" 
operating systems</a>. If you are interested in using the emulator to 
develop code on your own, then you should also read the section about
<a href="experiments.html#hello">Hello World</a>.

<p>
To exit the emulator, type CTRL-C to enter the 
single-step debugger, and then type <tt><b>quit</b></tt>.

<p>
If you are starting an emulation by entering settings directly on the 
command line, and you are not using the <tt><b>-x</b></tt> option, then all 
terminal input and output will go to the main controlling terminal.
CTRL-C is used to break into the debugger, so in order to send CTRL-C to 
the running (emulated) program, you may use CTRL-B.
(This should be a reasonable compromise to allow the emulator to be usable
even on systems without X Windows.)

<p>
There is no way to send an actual CTRL-B to the emulated program, when
typing in the main controlling terminal window. The solution is to either
use <a href="configfiles.html">configuration files</a>, or use
<tt><b>-x</b></tt>. Both these solutions cause new xterms to be opened for 
each emulated serial port that is written to. CTRL-B and CTRL-C both have 
their original meaning in those xterm windows.


<p><br>
<a name="cpus"></a>
<h3>Which processor architectures does GXemul emulate?</h3>

The architectures that are emulated well enough to let at least one 
guest operating system run (per architecture) are ARM, MIPS, PowerPC,
and SuperH.

<p>Please read the page about <a href="guestoses.html">guest operating
systems</a> for more information about the machines and operating systems 
that can be considered "working" in the emulator.


<p><br>
<a name="hosts"></a>
<h3>Which host architectures are supported?</h3>

GXemul should compile and run on any modern host architecture (64-bit or 
32-bit word-length).

<p>Note: The <a href="translation.html">dynamic translation</a> engine 
does <i>not</i> require backends for native code generation to be written 
for each individual host architecture; the intermediate representation 
that the dyntrans system uses can be executed on any host architecture.


<p><br>
<a name="accuracy"></a>
<h3>Emulation accuracy:</h3>

GXemul is an instruction-level emulator; things that would happen in
several steps within a real CPU are not taken into account (e.g. pipe-line
stalls or out-of-order execution). Still, instruction-level accuracy seems
to be enough to be able to run complete guest operating systems inside the
emulator.

<p>The existance of instruction and data caches is "faked" to let
operating systems think that they are there, but for all practical
purposes, these caches are non-working.

<p>The emulator is in general <i>not</i> timing-accurate, neither at the
instruction level nor on any higher level. An attempt is made to let
emulated clocks run at the same speed as the host (i.e. an emulated timer
running at 100 Hz will interrupt around 100 times per real second), but
since the host speed may vary, e.g. because of other running processes,
there is no guarantee as to how many instructions will be executed in
each of these 100 Hz cycles.

<p>If the host is very slow, the emulated clocks might even lag behind
the real-world clock.


<p><br>
<a name="emulmodes"></a>
<h3>Which machines does GXemul emulate?</h3>

A few different machine types are emulated. The following machine types 
are emulated well enough to run at least one "guest OS":

<p>
<ul>
  <li><b><u>ARM</u></b>
  <ul>
    <li><b>CATS</b> (<a href="guestoses.html#netbsdcatsinstall">NetBSD/cats</a>,
        <a href="guestoses.html#openbsdcatsinstall">OpenBSD/cats</a>)
    <li><b>IQ80321</b> (<a href="guestoses.html#netbsdevbarminstall">NetBSD/evbarm</a>)
    <li><b>NetWinder</b> (<a href="guestoses.html#netbsdnetwinderinstall">NetBSD/netwinder</a>)
  </ul>
  <p>
  <li><b><u>MIPS</u></b>
  <ul>
    <li><b>DECstation 5000/200</b> (<a href="guestoses.html#netbsdpmaxinstall">NetBSD/pmax</a>,
        <a href="guestoses.html#openbsdpmaxinstall">OpenBSD/pmax</a>,
        <a href="guestoses.html#ultrixinstall">Ultrix</a>,
        <a href="guestoses.html#declinux">Linux/DECstation</a>,
        <a href="guestoses.html#sprite">Sprite</a>)
    <li><b>Acer Pica-61</b> (<a href="guestoses.html#netbsdarcinstall">NetBSD/arc</a>)
    <li><b>NEC MobilePro 770, 780, 800, 880</b> (<a href="guestoses.html#netbsdhpcmipsinstall">NetBSD/hpcmips</a>)
    <li><b>Cobalt</b> (<a href="guestoses.html#netbsdcobaltinstall">NetBSD/cobalt</a>)
    <li><b>Malta</b> (<a href="guestoses.html#netbsdevbmipsinstall">NetBSD/evbmips</a>, Linux/Malta <font color="#0000e0">(<super>*1</super>)</font>)
    <li><b>Algorithmics P5064</b> (<a href="guestoses.html#netbsdalgorinstall">NetBSD/algor</a>)
    <li><b>SGI O2 (aka IP32)</b> <font color="#0000e0">(<super>*2</super>)</font>
        (<a href="guestoses.html#netbsdsgimips">NetBSD/sgi</a>)
  </ul>
  <p>
  <li><b><u>PowerPC</u></b>
  <ul>
    <li><b>IBM 6050/6070 (PReP, PowerPC Reference Platform)</b> (<a href="guestoses.html#netbsdprepinstall">NetBSD/prep</a>)
    <li><b>MacPPC (generic "G4" Macintosh)</b> (<a href="guestoses.html#netbsdmacppcinstall">NetBSD/macppc</a>)
  </ul>
  <p>
  <li><b><u>SuperH</u></b>
  <ul>
    <li><b>Sega Dreamcast</b> (<a href="dreamcast.html#netbsd_generic_md">NetBSD/dreamcast</a>, <a href="dreamcast.html#linux_live_cd">Linux/dreamcast</a>)
  </ul>
</ul>

<p>
<small><font color="#0000e0">(<super>*1</super>)</font> =
Linux/Malta may be run as a guest OS, however I have not yet found any stable
URL to pre-compiled Linux/Malta kernels. Thus, Linux/Malta emulation is not
tested for every release of the emulator; sometimes it works, sometimes
it doesn't.</small>

<br><small><font color="#0000e0">(<super>*2</super>)</font> =
SGI O2 emulation is enough for root-on-nfs, but not for disk boot.</small>


<p>There is code in GXemul for emulation of many other machine types; the
degree to which these work range from almost being able to run a complete
OS, to almost completely unsupported (perhaps just enough support to
output a few boot messages via serial console).

<p>In addition to emulating real machines, there is also a "test-machine".
A test-machine consists of one or more CPUs and a few experimental devices
such as:

<p>
<ul>
  <li>a console I/O device (putchar() and getchar()...)
  <li>an inter-processor communication device, for SMP experiments
  <li>a very simple linear framebuffer device (for graphics output)
  <li>a simple disk controller
  <li>a simple ethernet controller
  <li>a real-time clock device
</ul>

<p>This mode is useful if you wish to run experimental code, but do not
wish to target any specific real-world machine type, for example for
educational purposes.

<p>You can read more about these experimental devices <a
href="experiments.html#expdevices">here</a>.


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1	dpavlin	12	<html><head><title>Gavare's eXperimental Emulator:   Introduction</title>
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7	dpavlin	22	<b>Gavare's eXperimental Emulator:</b></font><br>
8	dpavlin	4	<font color="#000000" size="6"><b>Introduction</b>
9			</font></td></tr></table></td></tr></table><p>
10	dpavlin	2
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13	dpavlin	38	$Id: intro.html,v 1.108 2007/04/12 16:57:22 debug Exp $
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15	dpavlin	34	Copyright (C) 2003-2007 Anders Gavare. All rights reserved.
16	dpavlin	2
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18			modification, are permitted provided that the following conditions are met:
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41
42			<a href="./">Back to the index</a>
43
44			<p><br>
45			<h2>Introduction</h2>
46
47			<p>
48	dpavlin	22	<table border="0" width="99%"><tr><td valign="top" align="left">
49	dpavlin	2	<ul>
50			<li><a href="#overview">Overview</a>
51	dpavlin	4	<li><a href="#free">Is GXemul Free software?</a>
52	dpavlin	2	<li><a href="#build">How to compile/build the emulator</a>
53	dpavlin	6	<li><a href="#run">How to run the emulator</a>
54	dpavlin	22	<li><a href="#cpus">Which processor architectures does GXemul emulate?</a>
55	dpavlin	24	<li><a href="#hosts">Which host architectures are supported?</a>
56	dpavlin	2	<li><a href="#accuracy">Emulation accuracy</a>
57			<li><a href="#emulmodes">Which machines does GXemul emulate?</a>
58			</ul>
59	dpavlin	22	</td><td valign="center" align="center">
60			<a href="20050317-example.png"><img src="20050317-example_small.png"></a>
61			<p>NetBSD/pmax 1.6.2 with X11<br>running in GXemul</td></tr></table>
62	dpavlin	2
63
64
65
66			<p><br>
67			<a name="overview"></a>
68			<h3>Overview:</h3>
69
70	dpavlin	14	GXemul is an experimental instruction-level machine emulator. Several
71			emulation modes are available. In some modes, processors and surrounding
72			hardware components are emulated well enough to let unmodified operating
73			systems (e.g. NetBSD) run as if they were running on a real machine.
74	dpavlin	2
75	dpavlin	32	<p>Devices and processors are not simulated with 100% accuracy. They are
76			only ``faked'' well enough to allow guest operating systems to run without
77			complaining too much. Still, the emulator could be of interest for
78			academic research and experiments, such as when learning how to write
79			operating system code.
80	dpavlin	12
81	dpavlin	22	<p>The emulator is written in C, does not depend on third-party libraries,
82			and should compile and run on most 64-bit and 32-bit Unix-like systems.
83	dpavlin	2
84	dpavlin	10	<p>The emulator contains code which tries to emulate the workings of CPUs
85			and surrounding hardware found in real machines, but it does not contain
86			any ROM code. You will need some form of program (in binary form) to run
87			in the emulator. For many emulation modes, PROM calls are handled by the
88	dpavlin	2	emulator itself, so you do not need to use any ROM image at all.
89
90	dpavlin	10	<p>You can use pre-compiled kernels (for example NetBSD kernels, or
91			Linux), or other programs that are in binary format, and in some cases
92			even actual ROM images. A couple of different file formats are supported
93			(ELF, a.out, ECOFF, SREC, and raw binaries).
94	dpavlin	2
95	dpavlin	10	<p>If you do not have a kernel as a separate file, but you have a bootable
96	dpavlin	6	disk image, then it is sometimes possible to boot directly from that
97	dpavlin	34	image. (This works for example with DECstation emulation, Dreamcast
98			emulation, or when booting from generic ISO9660 CDROM images if the
99			kernel is included in the image as a plain file.)
100	dpavlin	2
101	dpavlin	32	<p>Thanks to (in no specific order) Joachim Buss, Olivier Houchard, Juli
102			Mallett, Juan Romero Pardines, Alec Voropay, Göran Weinholt, Alexander
103			Yurchenko, and everyone else who has provided me with feedback.
104	dpavlin	2
105
106
107	dpavlin	6
108
109	dpavlin	10
110
111	dpavlin	2	<p><br>
112			<a name="free"></a>
113	dpavlin	4	<h3>Is GXemul Free software?</h3>
114	dpavlin	2
115	dpavlin	6	Yes. I have released GXemul under a Free license. The code in GXemul is
116			Copyrighted software, it is <i>not</i> public domain. (If this is
117			confusing to you, you might want to read up on the definitions of the
118			four freedoms associated with Free software, <a
119			href="http://www.gnu.org/philosophy/free-sw.html">http://www.gnu.org/philosophy/free-sw.html</a>.)
120	dpavlin	2
121	dpavlin	12	<p>The code I have written is released under a 3-clause BSD-style license
122			(or "revised BSD-style" if one wants to use <a
123			href="http://www.gnu.org/philosophy/bsd.html">GNU jargon</a>). Apart from
124			the code I have written, some files are copied from other sources such as
125			NetBSD, for example header files containing symbolic names of bitfields in
126			device registers. They are also covered by similar licenses, but with some
127			additional clauses. The main point, however, is that the licenses require
128			that the original Copyright and license terms are included when you make a
129			copy or modification.
130	dpavlin	2
131	dpavlin	12	<p>If you plan to redistribute GXemul <i>without</i> supplying the source
132			code, then you need to comply with each individual source file some other
133			way, for example by writing additional documentation containing copyright
134			notes. I have not done this, since I do not plan on making distributions
135			without source code. You need to check all individual files for details.
136			The "easiest way out" if you plan to redistribute code from GXemul is, of
137			course, to let it remain open source and simply supply the source code.
138	dpavlin	2
139	dpavlin	22	<p>In case you want to reuse parts of GXemul, but you need to do that
140			under a different license (e.g. the GPL), then contact me and I might
141			re-license/dual-license files on a case-by-case basis.
142	dpavlin	2
143
144
145
146	dpavlin	12
147	dpavlin	2	<p><br>
148			<a name="build"></a>
149			<h3>How to compile/build the emulator:</h3>
150
151			Uncompress the .tar.gz distribution file, and run
152			<pre>
153			$ <b>./configure</b>
154			$ <b>make</b>
155			</pre>
156
157	dpavlin	22	<p>This should work on most Unix-like systems. GXemul does not require any
158			specific libraries to build, however, if you build on a system which does
159			not have X11 libraries installed, some functionality will be lost.
160	dpavlin	2
161	dpavlin	12	<p>The emulator's performance is highly dependent on both runtime settings
162	dpavlin	2	and on compiler settings, so you might want to experiment with different
163	dpavlin	20	CC and CFLAGS environment variable values. For example, on an AMD Athlon
164	dpavlin	24	host, you might want to try setting <tt>CFLAGS</tt> to <tt>-march=athlon</tt>
165			before running <tt>configure</tt>.
166	dpavlin	2
167
168	dpavlin	6
169
170
171
172
173			<p><br>
174			<a name="run"></a>
175			<h3>How to run the emulator:</h3>
176
177			Once you have built GXemul, running it should be rather straight-forward.
178			Running <tt><b>gxemul</b></tt> without arguments (or with the
179			<b><tt>-h</tt></b> or <b><tt>-H</tt></b> command line options) will
180			display a help message.
181
182	dpavlin	2	<p>
183	dpavlin	6	To get some ideas about what is possible to run in the emulator, please
184			read the section about <a href="guestoses.html">installing "guest"
185			operating systems</a>. If you are interested in using the emulator to
186			develop code on your own, then you should also read the section about
187			<a href="experiments.html#hello">Hello World</a>.
188
189			<p>
190	dpavlin	2	To exit the emulator, type CTRL-C to enter the
191	dpavlin	6	single-step debugger, and then type <tt><b>quit</b></tt>.
192	dpavlin	2
193	dpavlin	4	<p>
194			If you are starting an emulation by entering settings directly on the
195	dpavlin	6	command line, and you are not using the <tt><b>-x</b></tt> option, then all
196	dpavlin	4	terminal input and output will go to the main controlling terminal.
197			CTRL-C is used to break into the debugger, so in order to send CTRL-C to
198			the running (emulated) program, you may use CTRL-B.
199	dpavlin	6	(This should be a reasonable compromise to allow the emulator to be usable
200			even on systems without X Windows.)
201	dpavlin	2
202	dpavlin	4	<p>
203	dpavlin	6	There is no way to send an actual CTRL-B to the emulated program, when
204			typing in the main controlling terminal window. The solution is to either
205			use <a href="configfiles.html">configuration files</a>, or use
206			<tt><b>-x</b></tt>. Both these solutions cause new xterms to be opened for
207			each emulated serial port that is written to. CTRL-B and CTRL-C both have
208			their original meaning in those xterm windows.
209	dpavlin	2
210
211
212
213	dpavlin	4
214	dpavlin	2	<p><br>
215			<a name="cpus"></a>
216	dpavlin	22	<h3>Which processor architectures does GXemul emulate?</h3>
217	dpavlin	2
218	dpavlin	24	The architectures that are emulated well enough to let at least one
219	dpavlin	32	guest operating system run (per architecture) are ARM, MIPS, PowerPC,
220			and SuperH.
221	dpavlin	2
222	dpavlin	34	<p>Please read the page about <a href="guestoses.html">guest operating
223			systems</a> for more information about the machines and operating systems
224			that can be considered "working" in the emulator.
225	dpavlin	2
226
227
228	dpavlin	14
229	dpavlin	32
230	dpavlin	34
231	dpavlin	24	<p><br>
232			<a name="hosts"></a>
233			<h3>Which host architectures are supported?</h3>
234	dpavlin	2
235	dpavlin	32	GXemul should compile and run on any modern host architecture (64-bit or
236			32-bit word-length).
237	dpavlin	2
238	dpavlin	38	<p>Note: The <a href="translation.html">dynamic translation</a> engine
239			does <i>not</i> require backends for native code generation to be written
240			for each individual host architecture; the intermediate representation
241			that the dyntrans system uses can be executed on any host architecture.
242	dpavlin	6
243	dpavlin	2
244
245
246	dpavlin	32
247	dpavlin	24	<p><br>
248	dpavlin	2	<a name="accuracy"></a>
249			<h3>Emulation accuracy:</h3>
250
251	dpavlin	6	GXemul is an instruction-level emulator; things that would happen in
252	dpavlin	24	several steps within a real CPU are not taken into account (e.g. pipe-line
253	dpavlin	6	stalls or out-of-order execution). Still, instruction-level accuracy seems
254			to be enough to be able to run complete guest operating systems inside the
255	dpavlin	2	emulator.
256
257	dpavlin	24	<p>The existance of instruction and data caches is "faked" to let
258			operating systems think that they are there, but for all practical
259			purposes, these caches are non-working.
260	dpavlin	2
261	dpavlin	32	<p>The emulator is in general <i>not</i> timing-accurate, neither at the
262			instruction level nor on any higher level. An attempt is made to let
263			emulated clocks run at the same speed as the host (i.e. an emulated timer
264			running at 100 Hz will interrupt around 100 times per real second), but
265			since the host speed may vary, e.g. because of other running processes,
266			there is no guarantee as to how many instructions will be executed in
267			each of these 100 Hz cycles.
268	dpavlin	2
269	dpavlin	32	<p>If the host is very slow, the emulated clocks might even lag behind
270			the real-world clock.
271	dpavlin	2
272
273	dpavlin	6
274
275	dpavlin	20
276
277	dpavlin	2	<p><br>
278			<a name="emulmodes"></a>
279			<h3>Which machines does GXemul emulate?</h3>
280
281	dpavlin	4	A few different machine types are emulated. The following machine types
282			are emulated well enough to run at least one "guest OS":
283	dpavlin	2
284			<p>
285			<ul>
286	dpavlin	24	<li><b><u>ARM</u></b>
287	dpavlin	14	<ul>
288	dpavlin	28	<li><b>CATS</b> (<a href="guestoses.html#netbsdcatsinstall">NetBSD/cats</a>,
289			<a href="guestoses.html#openbsdcatsinstall">OpenBSD/cats</a>)
290			<li><b>IQ80321</b> (<a href="guestoses.html#netbsdevbarminstall">NetBSD/evbarm</a>)
291	dpavlin	30	<li><b>NetWinder</b> (<a href="guestoses.html#netbsdnetwinderinstall">NetBSD/netwinder</a>)
292	dpavlin	14	</ul>
293			<p>
294	dpavlin	24	<li><b><u>MIPS</u></b>
295	dpavlin	14	<ul>
296	dpavlin	28	<li><b>DECstation 5000/200</b> (<a href="guestoses.html#netbsdpmaxinstall">NetBSD/pmax</a>,
297			<a href="guestoses.html#openbsdpmaxinstall">OpenBSD/pmax</a>,
298			<a href="guestoses.html#ultrixinstall">Ultrix</a>,
299			<a href="guestoses.html#declinux">Linux/DECstation</a>,
300			<a href="guestoses.html#sprite">Sprite</a>)
301			<li><b>Acer Pica-61</b> (<a href="guestoses.html#netbsdarcinstall">NetBSD/arc</a>)
302	dpavlin	32	<li><b>NEC MobilePro 770, 780, 800, 880</b> (<a href="guestoses.html#netbsdhpcmipsinstall">NetBSD/hpcmips</a>)
303	dpavlin	28	<li><b>Cobalt</b> (<a href="guestoses.html#netbsdcobaltinstall">NetBSD/cobalt</a>)
304	dpavlin	34	<li><b>Malta</b> (<a href="guestoses.html#netbsdevbmipsinstall">NetBSD/evbmips</a>, Linux/Malta <font color="#0000e0">(<super>*1</super>)</font>)
305	dpavlin	30	<li><b>Algorithmics P5064</b> (<a href="guestoses.html#netbsdalgorinstall">NetBSD/algor</a>)
306	dpavlin	34	<li><b>SGI O2 (aka IP32)</b> <font color="#0000e0">(<super>*2</super>)</font>
307	dpavlin	28	(<a href="guestoses.html#netbsdsgimips">NetBSD/sgi</a>)
308	dpavlin	14	</ul>
309	dpavlin	20	<p>
310			<li><b><u>PowerPC</u></b>
311			<ul>
312	dpavlin	28	<li><b>IBM 6050/6070 (PReP, PowerPC Reference Platform)</b> (<a href="guestoses.html#netbsdprepinstall">NetBSD/prep</a>)
313	dpavlin	34	<li><b>MacPPC (generic "G4" Macintosh)</b> (<a href="guestoses.html#netbsdmacppcinstall">NetBSD/macppc</a>)
314	dpavlin	20	</ul>
315	dpavlin	32	<p>
316			<li><b><u>SuperH</u></b>
317			<ul>
318	dpavlin	36	<li><b>Sega Dreamcast</b> (<a href="dreamcast.html#netbsd_generic_md">NetBSD/dreamcast</a>, <a href="dreamcast.html#linux_live_cd">Linux/dreamcast</a>)
319	dpavlin	32	</ul>
320	dpavlin	2	</ul>
321
322	dpavlin	32	<p>
323			<small><font color="#0000e0">(<super>*1</super>)</font> =
324	dpavlin	34	Linux/Malta may be run as a guest OS, however I have not yet found any stable
325			URL to pre-compiled Linux/Malta kernels. Thus, Linux/Malta emulation is not
326			tested for every release of the emulator; sometimes it works, sometimes
327			it doesn't.</small>
328
329	dpavlin	32	<br><small><font color="#0000e0">(<super>*2</super>)</font> =
330	dpavlin	34	SGI O2 emulation is enough for root-on-nfs, but not for disk boot.</small>
331	dpavlin	22
332	dpavlin	34
333	dpavlin	10	<p>There is code in GXemul for emulation of many other machine types; the
334			degree to which these work range from almost being able to run a complete
335			OS, to almost completely unsupported (perhaps just enough support to
336			output a few boot messages via serial console).
337	dpavlin	2
338	dpavlin	10	<p>In addition to emulating real machines, there is also a "test-machine".
339			A test-machine consists of one or more CPUs and a few experimental devices
340			such as:
341	dpavlin	2
342			<p>
343			<ul>
344			<li>a console I/O device (putchar() and getchar()...)
345			<li>an inter-processor communication device, for SMP experiments
346			<li>a very simple linear framebuffer device (for graphics output)
347	dpavlin	32	<li>a simple disk controller
348	dpavlin	12	<li>a simple ethernet controller
349	dpavlin	32	<li>a real-time clock device
350	dpavlin	2	</ul>
351
352	dpavlin	10	<p>This mode is useful if you wish to run experimental code, but do not
353	dpavlin	2	wish to target any specific real-world machine type, for example for
354			educational purposes.
355
356	dpavlin	10	<p>You can read more about these experimental devices <a
357			href="experiments.html#expdevices">here</a>.
358	dpavlin	2
359
360
361
362
363
364			</body>
365			</html>