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$Id: HISTORY,v 1.1613 2007/06/15 20:11:26 debug Exp $
20070501	Continuing a little on m88k disassembly (control registers,
		more instructions).
		Adding a dummy mvme88k machine mode.
20070502	Re-adding MIPS load/store alignment exceptions.
20070503	Implementing more of the M88K disassembly code.
20070504	Adding disassembly of some more M88K load/store instructions.
		Implementing some relatively simple M88K instructions (br.n,
		xor[.u] imm, and[.u] imm).
20070505	Implementing M88K three-register and, or, xor, and jmp[.n],
		bsr[.n] including function call trace stuff.
		Applying a patch from Bruce M. Simpson which implements the
		SYSCON_BOARD_CPU_CLOCK_FREQ_ID object of the syscon call in
		the yamon PROM emulation.
20070506	Implementing M88K bb0[.n] and bb1[.n], and skeletons for
		ldcr and stcr (although no control regs are implemented yet).
20070509	Found and fixed the bug which caused Linux for QEMU_MIPS to
		stop working in 0.4.5.1: It was a faulty change to the MIPS
		'sc' and 'scd' instructions I made while going through gcc -W
		warnings on 20070428.
20070510	Updating the Linux/QEMU_MIPS section in guestoses.html to
		use mips-test-0.2.tar.gz instead of 0.1.
		A big thank you to Miod Vallat for sending me M88K manuals.
		Implementing more M88K instructions (addu, subu, div[u], mulu,
		ext[u], clr, set, cmp).
20070511	Fixing bugs in the M88K "and" and "and.u" instructions (found
		by comparing against the manual).
		Implementing more M88K instructions (mask[.u], mak, bcnd (auto-
		generated)) and some more control register details.
		Cleanup: Removing the experimental AVR emulation mode and
		corresponding devices; AVR emulation wasn't really meaningful.
		Implementing autogeneration of most M88K loads/stores. The
		rectangle drawing demo (with -O0) for M88K runs :-)
		Beginning on M88K exception handling.
		More M88K instructions: tb0, tb1, rte, sub, jsr[.n].
		Adding some skeleton MVME PROM ("BUG") emulation.
20070512	Fixing a bug in the M88K cmp instruction.
		Adding the M88K lda (scaled register) instruction.
		Fixing bugs in 64-bit (32-bit pairs) M88K loads/stores.
		Removing the unused tick_hz stuff from the machine struct.
		Implementing the M88K xmem instruction. OpenBSD/mvme88k gets
		far enough to display the Copyright banner :-)
		Implementing subu.co (guess), addu.co, addu.ci, ff0, and ff1.
		Adding a dev_mvme187, for MVME187-specific devices/registers.
		OpenBSD/mvme88k prints more boot messages. :)
20070515	Continuing on MVME187 emulation (adding more devices, beginning
		on the CMMUs, etc).
		Adding the M88K and.c, xor.c, and or.c instructions, and making
		sure that mul, div, etc cause exceptions if executed when SFD1
		is disabled.
20070517	Continuing on M88K and MVME187 emulation in general; moving
		the CMMU registers to the CPU struct, separating dev_pcc2 from
		dev_mvme187, and beginning on memory_m88k.c (BATC and PATC).
		Fixing a bug in 64-bit (32-bit pairs) M88K fast stores.
		Implementing the clock part of dev_mk48txx.
		Implementing the M88K fstcr and xcr instructions.
		Implementing m88k_cpu_tlbdump().
		Beginning on the implementation of a separate address space
		for M88K .usr loads/stores.
20070520	Removing the non-working (skeleton) Sandpoint, SonyNEWS, SHARK
		Dnard, and Zaurus machine modes.
		Experimenting with dyntrans to_be_translated read-ahead. It
		seems to give a very small performance increase for MIPS
		emulation, but a large performance degradation for SuperH. Hm.
20070522	Disabling correct SuperH ITLB emulation; it does not seem to be
		necessary in order to let SH4 guest OSes run, and it slows down
		userspace code.
		Implementing "samepage" branches for SuperH emulation, and some
		other minor speed hacks.
20070525	Continuing on M88K memory-related stuff: exceptions, memory
		transaction register contents, etc.
		Implementing the M88K subu.ci instruction.
		Removing the non-working (skeleton) Iyonix machine mode.
		OpenBSD/mvme88k reaches userland :-), starts executing
		/sbin/init's instructions, and issues a few syscalls, before
		crashing.
20070526	Fixing bugs in dev_mk48txx, so that OpenBSD/mvme88k detects
		the correct time-of-day.
		Implementing a generic IRQ controller for the test machines
		(dev_irqc), similar to a proposed patch from Petr Stepan.
		Experimenting some more with translation read-ahead.
		Adding an "expect" script for automated OpenBSD/landisk
		install regression/performance tests.
20070527	Adding a dummy mmEye (SH3) machine mode skeleton.
		FINALLY found the strange M88K bug I have been hunting: I had
		not emulated the SNIP value for exceptions occurring in
		branch delay slots correctly.
		Implementing correct exceptions for 64-bit M88K loads/stores.
		Address to symbol lookups are now disabled when M88K is
		running in usermode (because usermode addresses don't have
		anything to do with supervisor addresses).
20070531	Removing the mmEye machine mode skeleton.
20070604	Some minor code cleanup.
20070605	Moving src/useremul.c into a subdir (src/useremul/), and
		cleaning up some more legacy constructs.
		Adding -Wstrict-aliasing and -fstrict-aliasing detection to
		the configure script.
20070606	Adding a check for broken GCC on Solaris to the configure
		script. (GCC 3.4.3 on Solaris cannot handle static variables
		which are initialized to 0 or NULL. :-/)
		Removing the old (non-working) ARC emulation modes: NEC RD94,
		R94, R96, and R98, and the last traces of Olivetti M700 and
		Deskstation Tyne.
		Removing the non-working skeleton WDSC device (dev_wdsc).
20070607	Thinking about how to use the host's cc + ld at runtime to
		generate native code. (See experiments/native_cc_ld_test.i
		for an example.)
20070608	Adding a program counter sampling timer, which could be useful
		for native code generation experiments.
		The KN02_CSR_NRMMOD bit in the DECstation 5000/200 (KN02) CSR
		should always be set, to allow a 5000/200 PROM to boot.
20070609	Moving out breakpoint details from the machine struct into
		a helper struct, and removing the limit on max nr of
		breakpoints.
20070610	Moving out tick functions into a helper struct as well (which
		also gets rid of the max limit).
20070612	FINALLY figured out why Debian/DECstation stopped working when
		translation read-ahead was enabled: in src/memory_rw.c, the
		call to invalidate_code_translation was made also if the
		memory access was an instruction load (if the page was mapped
		as writable); it shouldn't be called in that case.
20070613	Implementing some more MIPS32/64 revision 2 instructions: di,
		ei, ext, dext, dextm, dextu, and ins.
20070614	Implementing an instruction combination for the NetBSD/arm
		idle loop (making the host not use any cpu if NetBSD/arm
		inside the emulator is not using any cpu).
		Increasing the nr of ARM VPH entries from 128 to 384.
20070615	Removing the ENABLE_arch stuff from the configure script, so
		that all included architectures are included in both release
		and development builds.
		Moving memory related helper functions from misc.c to memory.c.
		Adding preliminary instructions for netbooting NetBSD/pmppc to
		guestoses.html; it doesn't work yet, there are weird timeouts.
		Beginning a total rewrite of the userland emulation modes
		(removing all emulation modes, beginning from scratch with
		NetBSD/MIPS and FreeBSD/Alpha only).
20070616	After fixing a bug in the DEC21143 NIC (the TDSTAT_OWN bit was
		only cleared for the last segment when transmitting, not all
		segments), NetBSD/pmppc boots with root-on-nfs without the
		timeouts. Updating guestoses.html.
		Removing the skeleton PSP (Playstation Portable) mode.
		Moving X11-related stuff in the machine struct into a helper
		struct.
		Cleanup of out-of-memory checks, to use a new CHECK_ALLOCATION
		macro (which prints a meaningful error message).
		Adding a COMMENT to each machine and device (for automagic
		.index comment generation).
		Doing regression testing for the next release.

==============  RELEASE 0.4.6  ==============


1 <html><head><title>Gavare's eXperimental Emulator:&nbsp;&nbsp;&nbsp;Introduction</title>
2 <meta name="robots" content="noarchive,nofollow,noindex"></head>
3 <body bgcolor="#f8f8f8" text="#000000" link="#4040f0" vlink="#404040" alink="#ff0000">
4 <table border=0 width=100% bgcolor="#d0d0d0"><tr>
5 <td width=100% align=center valign=center><table border=0 width=100%><tr>
6 <td align="left" valign=center bgcolor="#d0efff"><font color="#6060e0" size="6">
7 <b>Gavare's eXperimental Emulator:</b></font><br>
8 <font color="#000000" size="6"><b>Introduction</b>
9 </font></td></tr></table></td></tr></table><p>
10
11 <!--
12
13 $Id: intro.html,v 1.118 2007/06/15 21:43:09 debug Exp $
14
15 Copyright (C) 2003-2007 Anders Gavare. All rights reserved.
16
17 Redistribution and use in source and binary forms, with or without
18 modification, are permitted provided that the following conditions are met:
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20 1. Redistributions of source code must retain the above copyright
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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 <table border="0" width="99%"><tr><td valign="top" align="left">
49 <ul>
50 <li><a href="#overview">Overview</a>
51 <li><a href="#free">Is GXemul Free software?</a>
52 <li><a href="#build">How to compile/build the emulator</a>
53 <li><a href="#run">How to run the emulator</a>
54 <li><a href="#cpus">Which processor architectures does GXemul emulate?</a>
55 <li><a href="#hosts">Which host architectures/platforms are supported?</a>
56 <li><a href="#accuracy">Emulation accuracy</a>
57 <li><a href="#emulmodes">Which machines does GXemul emulate?</a>
58 </ul>
59 </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
63
64
65
66 <p><br>
67 <a name="overview"></a>
68 <h3>Overview:</h3>
69
70 GXemul is an experimental <a href="#accuracy">instruction-level</a>
71 machine emulator. Several emulation modes are available. In some modes,
72 processors and surrounding hardware components are emulated well enough to
73 let <a href="#emulmodes">unmodified operating systems (e.g. NetBSD)
74 run</a> as if they were running on a real machine.
75
76 <p>The emulator is written in C, does not depend on third-party libraries,
77 and should compile and run on most 64-bit and 32-bit Unix-like systems,
78 with few or no modifications.
79
80 <p>Devices and processors are not simulated with 100% accuracy. They are
81 only ``faked'' well enough to allow guest operating systems to run without
82 complaining too much. Still, the emulator could be of interest for
83 academic research and experiments, such as when learning how to write
84 operating system code.
85
86 <p>The emulator contains code which tries to emulate the workings of CPUs
87 and surrounding hardware found in real machines, but it does not contain
88 any ROM code. You will need some form of program (in binary form) to run
89 in the emulator. For some emulation modes, PROM calls are handled by the
90 emulator itself, so you do not need to use any ROM image at all.
91
92 <p>You can use pre-compiled kernels (for example <a href="http://www.netbsd.org/">NetBSD</a>
93 kernels, or Linux), or other programs that are in binary format, and in some cases
94 even actual ROM images. A couple of different file formats are supported:
95 <a href="http://en.wikipedia.org/wiki/Executable_and_Linkable_Format">ELF</a>,
96 <a href="http://en.wikipedia.org/wiki/A.out">a.out</a>,
97 <a href="http://en.wikipedia.org/wiki/COFF">COFF</a>/<a href="http://en.wikipedia.org/wiki/ECOFF">ECOFF</a>,
98 <a href="http://en.wikipedia.org/wiki/SREC_%28file_format%29">SREC</a>, and raw binaries.
99
100 <p>If you do not have a kernel as a separate file, but you have a bootable
101 disk image, then it is sometimes possible to boot directly from that
102 image. This works for example with DECstation emulation, <a href="dreamcast.html">Dreamcast
103 emulation</a>, or when booting from generic <a href="http://en.wikipedia.org/wiki/ISO9660">ISO9660</a>
104 CDROM images if the kernel is included in the image as a plain file.
105
106 <p>Thanks to (in no specific order) Joachim Buss, Olivier Houchard, Juli
107 Mallett, Juan Romero Pardines, Carl van Schaik, Miod Vallat, Alec Voropay,
108 Göran Weinholt, Alexander Yurchenko, and everyone else who has provided me
109 with feedback.
110
111
112
113
114
115
116
117 <p><br>
118 <a name="free"></a>
119 <h3>Is GXemul Free software?</h3>
120
121 Yes. I have released GXemul under a Free license. The code in GXemul is
122 Copyrighted software, it is <i>not</i> public domain. (If this is
123 confusing to you, you might want to read up on the definitions of the
124 four freedoms associated with Free software, <a
125 href="http://www.gnu.org/philosophy/free-sw.html">http://www.gnu.org/philosophy/free-sw.html</a>.)
126
127 <p>The code I have written is released under a 3-clause BSD-style license
128 (or "revised BSD-style" if one wants to use <a
129 href="http://www.gnu.org/philosophy/bsd.html">GNU jargon</a>). Apart from
130 the code I have written, some files are copied from other sources such as
131 NetBSD, for example header files containing symbolic names of bitfields in
132 device registers. They are also covered by similar licenses, but with some
133 additional clauses. The main point, however, is that the licenses require
134 that the original Copyright and license terms are included when you make a
135 copy or modification.
136
137 <p>If you plan to redistribute GXemul <i>without</i> supplying the source
138 code, then you need to comply with each individual source file some other
139 way, for example by writing additional documentation containing copyright
140 notes. I have not done this, since I do not plan on making distributions
141 without source code. You need to check all individual files for details.
142 The "easiest way out" if you plan to redistribute code from GXemul is, of
143 course, to let it remain open source and simply supply the source code.
144
145 <p>In case you want to reuse parts of GXemul, but you need to do that
146 under a different license (e.g. the GPL), then contact me and I might
147 re-license/dual-license files on a case-by-case basis.
148
149
150
151
152
153 <p><br>
154 <a name="build"></a>
155 <h3>How to compile/build the emulator:</h3>
156
157 Uncompress the .tar.gz distribution file, and run
158 <pre>
159 $ <b>./configure</b>
160 $ <b>make</b>
161 </pre>
162
163 <p>This should work on most Unix-like systems. GXemul does not require any
164 specific libraries to build, however, if you build on a system which does
165 not have X11 libraries installed, some functionality will be lost.
166
167 <p>The emulator's performance is highly dependent on both runtime settings
168 and on compiler settings, so you might want to experiment with
169 using different CC and CFLAGS environment variable values when running the
170 <tt>configure</tt> script.
171
172 <p>Note that there is no <tt>make install</tt> functionality; package
173 maintainers for individual operating systems solve this for their
174 corresponding OSes.
175
176
177
178
179
180
181
182 <p><br>
183 <a name="run"></a>
184 <h3>How to run the emulator:</h3>
185
186 Once you have built GXemul, running it should be rather straight-forward.
187 Running <tt><b>gxemul</b></tt> without arguments (or with the
188 <b><tt>-h</tt></b> or <b><tt>-H</tt></b> command line options) will
189 display a help message.
190
191 <p>To get some ideas about what is possible to run in the emulator, please
192 read the section about <a href="guestoses.html">installing "guest"
193 operating systems</a>. The most straight forward guest operating to
194 install is NetBSD/pmax; the instructions provided <a
195 href="guestoses.html#netbsdpmaxinstall">here</a> should let you install
196 NetBSD/pmax in a way very similar to how it is done on a real DECstation.
197
198 <p>If you are interested in using the emulator to develop code on your
199 own, then you should also read the section about <a
200 href="experiments.html#hello">Hello World</a>.
201
202 <p>To exit the emulator, type CTRL-C to enter the
203 single-step debugger, and then type <tt><b>quit</b></tt>.
204
205 <p>If you are starting an emulation by entering settings directly on the
206 command line, and you are not using the <tt><b>-x</b></tt> option, then
207 all terminal input and output will go to the main controlling terminal.
208 CTRL-C is used to break into the debugger, so in order to send CTRL-C to
209 the running (emulated) program, you may use CTRL-B. (This should be a
210 reasonable compromise to allow the emulator to be usable even on systems
211 without X Windows.)
212
213 <p>There is no way to send an actual CTRL-B to the emulated program, when
214 typing in the main controlling terminal window. The solution is to either
215 use <a href="configfiles.html">configuration files</a>, or use
216 <tt><b>-x</b></tt>. Both these solutions cause new xterms to be opened for
217 each emulated serial port that is written to. CTRL-B and CTRL-C both have
218 their original meaning in those xterm windows.
219
220
221
222
223
224 <p><br>
225 <a name="cpus"></a>
226 <h3>Which processor architectures does GXemul emulate?</h3>
227
228 The architectures that are emulated well enough to let at least one
229 guest operating system run (per architecture) are ARM, MIPS, PowerPC,
230 and SuperH.
231
232 <p>Please read the page about <a href="guestoses.html">guest operating
233 systems</a> for more information about the machines and operating systems
234 that can be considered "working" in the emulator. (There is some code in
235 GXemul for emulation of other architectures, but they are not stable or
236 complete enough to be listed among the "working" architectures.)
237
238
239
240
241
242
243 <p><br>
244 <a name="hosts"></a>
245 <h3>Which host architectures/platforms are supported?</h3>
246
247 GXemul should compile and run on any modern host architecture (64-bit or
248 32-bit word-length). I generally test it on FreeBSD/amd64 6.x,
249 FreeBSD/alpha 4.x, sometimes also on Linux (various platforms), and every
250 now and then also on NetBSD inside the emulator itself (various platforms).
251
252 <p>Note 1: The <a href="translation.html">dynamic translation</a> engine
253 does <i>not</i> require backends for native code generation to be written
254 for each individual host architecture; the intermediate representation
255 that the dyntrans system uses can be executed on any host architecture.
256
257 <p>Note 2: Although GXemul may build and run on non-Unix-like platforms,
258 such as Cygwin, Unix-like systems are the primary platform. Some
259 functionality may be lost when running on Cygwin.
260
261
262
263
264
265
266
267
268 <p><br>
269 <a name="accuracy"></a>
270 <h3>Emulation accuracy:</h3>
271
272 GXemul is an instruction-level emulator; things that would happen in
273 several steps within a real CPU are not taken into account (e.g. pipe-line
274 stalls or out-of-order execution). Still, instruction-level accuracy seems
275 to be enough to be able to run complete guest operating systems inside the
276 emulator.
277
278 <p>The existance of instruction and data caches is "faked" to let
279 operating systems think that they are there, but for all practical
280 purposes, these caches are non-working.
281
282 <p>The emulator is in general <i>not</i> timing-accurate, neither at the
283 instruction level nor on any higher level. An attempt is made to let
284 emulated clocks run at the same speed as the host (i.e. an emulated timer
285 running at 100 Hz will interrupt around 100 times per real second), but
286 since the host speed may vary, e.g. because of other running processes,
287 there is no guarantee as to how many instructions will be executed in
288 each of these 100 Hz cycles.
289
290 <p>If the host is very slow, the emulated clocks might even lag behind
291 the real-world clock.
292
293
294
295
296
297
298 <p><br>
299 <a name="emulmodes"></a>
300 <h3>Which machines does GXemul emulate?</h3>
301
302 A few different machine types are emulated. The following machine types
303 are emulated well enough to run at least one "guest OS":
304
305 <p>
306 <ul>
307 <li><b><u>ARM</u></b>
308 <ul>
309 <li><b>CATS</b> (<a href="guestoses.html#netbsdcatsinstall">NetBSD/cats</a>,
310 <a href="guestoses.html#openbsdcatsinstall">OpenBSD/cats</a>)
311 <li><b>IQ80321</b> (<a href="guestoses.html#netbsdevbarminstall">NetBSD/evbarm</a>)
312 <li><b>NetWinder</b> (<a href="guestoses.html#netbsdnetwinderinstall">NetBSD/netwinder</a>)
313 </ul>
314 <p>
315 <li><b><u>MIPS</u></b>
316 <ul>
317 <li><b>DECstation 5000/200</b> (<a href="guestoses.html#netbsdpmaxinstall">NetBSD/pmax</a>,
318 <a href="guestoses.html#openbsdpmaxinstall">OpenBSD/pmax</a>,
319 <a href="guestoses.html#ultrixinstall">Ultrix</a>,
320 <a href="guestoses.html#declinux">Linux/DECstation</a>,
321 <a href="guestoses.html#sprite">Sprite</a>)
322 <li><b>Acer Pica-61</b> (<a href="guestoses.html#netbsdarcinstall">NetBSD/arc</a>)
323 <li><b>NEC MobilePro 770, 780, 800, 880</b> (<a href="guestoses.html#netbsdhpcmipsinstall">NetBSD/hpcmips</a>)
324 <li><b>Cobalt</b> (<a href="guestoses.html#netbsdcobaltinstall">NetBSD/cobalt</a>)
325 <li><b>Malta</b> (<a href="guestoses.html#netbsdevbmipsinstall">NetBSD/evbmips</a>, Linux/Malta <font color="#0000e0">(<super>*1</super>)</font>)
326 <li><b>Algorithmics P5064</b> (<a href="guestoses.html#netbsdalgorinstall">NetBSD/algor</a>)
327 <li><b>SGI O2 (aka IP32)</b> <font color="#0000e0">(<super>*2</super>)</font>
328 (<a href="guestoses.html#netbsdsgimips">NetBSD/sgi</a>)
329 </ul>
330 <p>
331 <li><b><u>PowerPC</u></b>
332 <ul>
333 <li><b>IBM 6050/6070 (PReP, PowerPC Reference Platform)</b> (<a href="guestoses.html#netbsdprepinstall">NetBSD/prep</a>)
334 <li><b>MacPPC (generic "G4" Macintosh)</b> (<a href="guestoses.html#netbsdmacppcinstall">NetBSD/macppc</a>)
335 <li><b>Artesyn PM/PPC</b> (<a href="guestoses.html#netbsdpmppc">NetBSD/pmppc</a>)
336 </ul>
337 <p>
338 <li><b><u>SuperH</u></b>
339 <ul>
340 <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>)
341 <li><b>Landisk I-O DATA USL-5P</b> (<a href="guestoses.html#openbsdlandiskinstall">OpenBSD/landisk</a>)
342 </ul>
343 </ul>
344
345 <p>
346 <small><font color="#0000e0">(<super>*1</super>)</font> =
347 Linux/Malta may be run as a guest OS, however I have not yet found any stable
348 URL to pre-compiled Linux/Malta kernels. Thus, Linux/Malta emulation is not
349 tested for every release of the emulator; sometimes it works, sometimes
350 it doesn't.</small>
351
352 <br><small><font color="#0000e0">(<super>*2</super>)</font> =
353 SGI O2 emulation is enough for root-on-nfs, but not for disk boot.</small>
354
355 <p>Note that of all of the machines above, none of them is emulated to
356 100%. The most complete emulation mode is probably the DECstation
357 5000/200. Things that will most likely <b>not</b> work include running
358 raw PROM images for most machines, SGI IRIX, MacOS X or Darwin, Windows
359 NT, or Dreamcast games.
360
361 <p>There is code in GXemul for emulation of several other machine types; the
362 degree to which these work range from almost being able to run a complete
363 OS, to almost completely unsupported, perhaps just enough support to
364 output a few boot messages via serial console. (See the end of
365 <a href="guestoses.html#generalnotes">this section</a> on the Guest OSes
366 page for some examples, but remember that these do not necessarily work.)
367
368 <p>In addition to emulating real machines, there is also a "test-machine".
369 A test-machine consists of one or more CPUs and a few experimental devices
370 such as:
371
372 <p>
373 <ul>
374 <li>a console I/O device (putchar() and getchar()...)
375 <li>an inter-processor communication device, for SMP experiments
376 <li>a very simple linear framebuffer device (for graphics output)
377 <li>a simple disk controller
378 <li>a simple ethernet controller
379 <li>a real-time clock device
380 </ul>
381
382 <p>This mode is useful if you wish to run experimental code, but do not
383 wish to target any specific real-world machine type, for example for
384 educational purposes.
385
386 <p>You can read more about these experimental devices <a
387 href="experiments.html#expdevices">here</a>.
388
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393
394 </body>
395 </html>

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