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20051126	Cobalt and PReP now work with the 21143 NIC.
		Continuing on Alpha dyntrans things.
		Fixing some more left-shift-by-24 to unsigned.
20051127	Working on OpenFirmware emulation; major cleanup/redesign.
		Progress on MacPPC emulation: NetBSD detects two CPUs (when
		running with -n 2), framebuffer output (for text) works.
		Adding quick-hack Bandit PCI controller and "gc" interrupt
		controller for MacPPC.
20051128	Changing from a Bandit to a Uni-North controller for macppc.
		Continuing on OpenFirmware and MacPPC emulation in general
		(obio controller, and wdc attached to the obio seems to work).
20051129	More work on MacPPC emulation (adding a dummy ADB controller).
		Continuing the PCI bus cleanup (endianness and tag composition)
		and rewriting all PCI controllers' access functions.
20051130	Various minor PPC dyntrans optimizations.
		Manually inlining some parts of the framebuffer redraw routine.
		Slowly beginning the conversion of the old MIPS emulation into
		dyntrans (but this will take quite some time to get right).
		Generalizing quick_pc_to_pointers.
20051201	Documentation update (David Muse has made available a kernel
		which simplifies Debian/DECstation installation).
		Continuing on the ADB bus controller.
20051202	Beginning a rewrite of the Zilog serial controller (dev_zs).
20051203	Continuing on the zs rewrite (now called dev_z8530); conversion
		to devinit style.
		Reworking some of the input-only vs output-only vs input-output
		details of src/console.c, better warning messages, and adding
		a debug dump.
		Removing the concept of "device state"; it wasn't really used.
		Changing some debug output (-vv should now be used to show all
		details about devices and busses; not shown during normal
		startup anymore).
		Beginning on some SPARC instruction disassembly support.
20051204	Minor PPC updates (WALNUT skeleton stuff).
		Continuing on the MIPS dyntrans rewrite.
		More progress on the ADB controller (a keyboard is "detected"
		by NetBSD and OpenBSD).
		Downgrading OpenBSD/arc as a guest OS from "working" to
		"almost working" in the documentation.
		Progress on Algor emulation ("v3" PCI controller).
20051205	Minor updates.
20051207	Sorting devices according to address; this reduces complexity
		of device lookups from O(n) to O(log n) in memory_rw (but no
		real performance increase (yet) in experiments).
20051210	Beginning the work on native dyntrans backends (by making a
		simple skeleton; so far only for Alpha hosts).
20051211	Some very minor SPARC updates.
20051215	Fixing a bug in the MIPS mul (note: not mult) instruction,
		so it also works with non-64-bit emulation. (Thanks to Alec
		Voropay for noticing the problem.)
20051216	More work on the fake/empty/simple/skeleton/whatever backend;
		performance doesn't increase, so this isn't really worth it,
		but it was probably worth it to prepare for a real backend
		later.
20051219	More instr call statistics gathering and analysis stuff.
20051220	Another fix for MIPS 'mul'. Also converting mul and {d,}cl{o,z}
		to dyntrans.
		memory_ppc.c syntax error fix (noticed by Peter Valchev).
		Beginning to move out machines from src/machine.c into
		individual files in src/machines (in a way similar to the
		autodev system for devices).
20051222	Updating the documentation regarding NetBSD/pmax 3.0.
20051223	- " - NetBSD/cats 3.0.
20051225	- " - NetBSD/hpcmips 3.0.
20051226	Continuing on the machine registry redesign.
		Adding support for ARM rrx (33-bit rotate).
		Fixing some signed/unsigned issues (exposed by gcc -W).
20051227	Fixing the bug which prevented a NetBSD/prep 3.0 install kernel
		from starting (triggered when an mtmsr was the last instruction
		on a page). Unfortunately not enough to get the kernel to run
		as well as the 2.1 kernels did.
20051230	Some dyntrans refactoring.
20051231	Continuing on the machine registry redesign.
20060101-10	Continuing... moving more machines. Moving MD interrupt stuff
		from machine.c into a new src/machines/interrupts.c.
20060114	Adding various mvmeppc machine skeletons.
20060115	Continuing on mvme* stuff. NetBSD/mvmeppc prints boot messages
		(for MVME1600) and reaches the root device prompt, but no
		specific hardware devices are emulated yet.
20060116	Minor updates to the mvme1600 emulation mode; the Eagle PCI bus
		seems to work without much modification, and a 21143 can be
		detected, interrupts might work (but untested so far).
		Adding a fake MK48Txx (mkclock) device, for NetBSD/mvmeppc.
20060121	Adding an aux control register for ARM. (A BIG thank you to
		Olivier Houchard for tracking down this bug.)
20060122	Adding more ARM instructions (smulXY), and dev_iq80321_7seg.
20060124	Adding disassembly of more ARM instructions (mia*, mra/mar),
		and some semi-bogus XScale and i80321 registers.
20060201-02	Various minor updates. Moving the last machines out of
		machine.c.
20060204	Adding a -c command line option, for running debugger commands
		before the simulation starts, but after all files have been
		loaded.
		Minor iq80321-related updates.
20060209	Minor hacks (DEVINIT macro, etc).
		Preparing for the generalization of the 64-bit dyntrans address
		translation subsystem.
20060216	Adding ARM ldrd (double-register load).
20060217	Continuing on various ARM-related stuff.
20060218	More progress on the ATA/wdc emulation for NetBSD/iq80321.
		NetBSD/evbarm can now be installed :-)  Updating the docs, etc.
		Continuing on Algor emulation.

==============  RELEASE 0.3.8  ==============


1 dpavlin 12 <html><head><title>Gavare's eXperimental Emulator:&nbsp;&nbsp;&nbsp;Introduction</title>
2     <meta name="robots" content="noarchive,nofollow,noindex"></head>
3 dpavlin 4 <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 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
11     <!--
12    
13 dpavlin 22 $Id: intro.html,v 1.73 2006/02/18 14:02:19 debug Exp $
14 dpavlin 2
15 dpavlin 22 Copyright (C) 2003-2006 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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20     1. Redistributions of source code must retain the above copyright
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39    
40     -->
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 2 <li><a href="#accuracy">Emulation accuracy</a>
56     <li><a href="#emulmodes">Which machines does GXemul emulate?</a>
57     </ul>
58 dpavlin 22 </td><td valign="center" align="center">
59     <a href="20050317-example.png"><img src="20050317-example_small.png"></a>
60     <p>NetBSD/pmax 1.6.2 with X11<br>running in GXemul</td></tr></table>
61 dpavlin 2
62    
63    
64    
65     <p><br>
66     <a name="overview"></a>
67     <h3>Overview:</h3>
68    
69 dpavlin 14 GXemul is an experimental instruction-level machine emulator. Several
70     emulation modes are available. In some modes, processors and surrounding
71     hardware components are emulated well enough to let unmodified operating
72     systems (e.g. NetBSD) run as if they were running on a real machine.
73 dpavlin 2
74 dpavlin 14 <p>The processor architecture best emulated by GXemul is MIPS, but other
75 dpavlin 20 architectures such as ARM and PowerPC are also partially emulated.
76 dpavlin 12
77 dpavlin 10 <p>Devices and CPUs are not simulated with 100% accuracy. They are only
78 dpavlin 20 ``faked'' well enough to allow guest operating systems run without
79 dpavlin 6 complaining too much. Still, the emulator could be of interest for
80     academic research and experiments, such as when learning how to write
81 dpavlin 4 operating system code.
82 dpavlin 2
83 dpavlin 22 <p>The emulator is written in C, does not depend on third-party libraries,
84     and should compile and run on most 64-bit and 32-bit Unix-like systems.
85 dpavlin 2
86 dpavlin 10 <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 many emulation modes, PROM calls are handled by the
90 dpavlin 2 emulator itself, so you do not need to use any ROM image at all.
91    
92 dpavlin 10 <p>You can use pre-compiled kernels (for example NetBSD kernels, or
93     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     (ELF, a.out, ECOFF, SREC, and raw binaries).
96 dpavlin 2
97 dpavlin 10 <p>If you do not have a kernel as a separate file, but you have a bootable
98 dpavlin 6 disk image, then it is sometimes possible to boot directly from that
99     image. (This works for example with DECstation emulation, or when booting
100     from ISO9660 CDROM images.)
101 dpavlin 2
102    
103    
104    
105 dpavlin 6
106    
107 dpavlin 10
108    
109 dpavlin 2 <p><br>
110     <a name="free"></a>
111 dpavlin 4 <h3>Is GXemul Free software?</h3>
112 dpavlin 2
113 dpavlin 6 Yes. I have released GXemul under a Free license. The code in GXemul is
114     Copyrighted software, it is <i>not</i> public domain. (If this is
115     confusing to you, you might want to read up on the definitions of the
116     four freedoms associated with Free software, <a
117     href="http://www.gnu.org/philosophy/free-sw.html">http://www.gnu.org/philosophy/free-sw.html</a>.)
118 dpavlin 2
119 dpavlin 12 <p>The code I have written is released under a 3-clause BSD-style license
120     (or "revised BSD-style" if one wants to use <a
121     href="http://www.gnu.org/philosophy/bsd.html">GNU jargon</a>). Apart from
122     the code I have written, some files are copied from other sources such as
123     NetBSD, for example header files containing symbolic names of bitfields in
124     device registers. They are also covered by similar licenses, but with some
125     additional clauses. The main point, however, is that the licenses require
126     that the original Copyright and license terms are included when you make a
127     copy or modification.
128 dpavlin 2
129 dpavlin 12 <p>If you plan to redistribute GXemul <i>without</i> supplying the source
130     code, then you need to comply with each individual source file some other
131     way, for example by writing additional documentation containing copyright
132     notes. I have not done this, since I do not plan on making distributions
133     without source code. You need to check all individual files for details.
134     The "easiest way out" if you plan to redistribute code from GXemul is, of
135     course, to let it remain open source and simply supply the source code.
136 dpavlin 2
137 dpavlin 22 <p>In case you want to reuse parts of GXemul, but you need to do that
138     under a different license (e.g. the GPL), then contact me and I might
139     re-license/dual-license files on a case-by-case basis.
140 dpavlin 2
141    
142    
143    
144 dpavlin 12
145 dpavlin 2 <p><br>
146     <a name="build"></a>
147     <h3>How to compile/build the emulator:</h3>
148    
149     Uncompress the .tar.gz distribution file, and run
150     <pre>
151     $ <b>./configure</b>
152     $ <b>make</b>
153     </pre>
154    
155 dpavlin 22 <p>This should work on most Unix-like systems. GXemul does not require any
156     specific libraries to build, however, if you build on a system which does
157     not have X11 libraries installed, some functionality will be lost.
158 dpavlin 2
159 dpavlin 12 <p>The emulator's performance is highly dependent on both runtime settings
160 dpavlin 2 and on compiler settings, so you might want to experiment with different
161 dpavlin 20 CC and CFLAGS environment variable values. For example, on an AMD Athlon
162     host, you might want to try setting <tt>CFLAGS</tt> to <tt>-march=athlon
163     -O3</tt> before running <tt>configure</tt>.
164 dpavlin 2
165    
166 dpavlin 6
167    
168    
169    
170    
171     <p><br>
172     <a name="run"></a>
173     <h3>How to run the emulator:</h3>
174    
175     Once you have built GXemul, running it should be rather straight-forward.
176     Running <tt><b>gxemul</b></tt> without arguments (or with the
177     <b><tt>-h</tt></b> or <b><tt>-H</tt></b> command line options) will
178     display a help message.
179    
180 dpavlin 2 <p>
181 dpavlin 6 To get some ideas about what is possible to run in the emulator, please
182     read the section about <a href="guestoses.html">installing "guest"
183     operating systems</a>. If you are interested in using the emulator to
184     develop code on your own, then you should also read the section about
185     <a href="experiments.html#hello">Hello World</a>.
186    
187     <p>
188 dpavlin 2 To exit the emulator, type CTRL-C to enter the
189 dpavlin 6 single-step debugger, and then type <tt><b>quit</b></tt>.
190 dpavlin 2
191 dpavlin 4 <p>
192     If you are starting an emulation by entering settings directly on the
193 dpavlin 6 command line, and you are not using the <tt><b>-x</b></tt> option, then all
194 dpavlin 4 terminal input and output will go to the main controlling terminal.
195     CTRL-C is used to break into the debugger, so in order to send CTRL-C to
196     the running (emulated) program, you may use CTRL-B.
197 dpavlin 6 (This should be a reasonable compromise to allow the emulator to be usable
198     even on systems without X Windows.)
199 dpavlin 2
200 dpavlin 4 <p>
201 dpavlin 6 There is no way to send an actual CTRL-B to the emulated program, when
202     typing in the main controlling terminal window. The solution is to either
203     use <a href="configfiles.html">configuration files</a>, or use
204     <tt><b>-x</b></tt>. Both these solutions cause new xterms to be opened for
205     each emulated serial port that is written to. CTRL-B and CTRL-C both have
206     their original meaning in those xterm windows.
207 dpavlin 2
208    
209    
210    
211 dpavlin 4
212 dpavlin 2 <p><br>
213     <a name="cpus"></a>
214 dpavlin 22 <h3>Which processor architectures does GXemul emulate?</h3>
215 dpavlin 2
216     <h4>MIPS:</h4>
217    
218 dpavlin 6 Emulation of R4000, which is a 64-bit CPU, was my initial goal.
219     R2000/R3000-like CPUs (32-bit), R1x000, and generic MIPS32/MIPS64-style
220     CPUs are also emulated, and are hopefully almost as stable as the R4000
221 dpavlin 20 emulation. Several guest operating systems for MIPS can run inside
222     the emulator.
223 dpavlin 2
224 dpavlin 20 <p>(For MIPS emulation, I have written an experimental dynamic binary
225     translation subsystem, for Alpha and i386 hosts. This gives higher total
226     performance than interpreting one instruction at a time and executing it.
227     If you wish to disable bintrans, add <b>-B</b> to the command line.)
228 dpavlin 2
229 dpavlin 14 <h4>ARM:</h4>
230 dpavlin 2
231 dpavlin 22 ARM emulation is good enough to run NetBSD/cats, OpenBSD/cats, and
232     NetBSD/evbarm, but it is not as tested or fine-tuned as the MIPS emulation
233     mode.
234 dpavlin 14
235 dpavlin 20 <h4>PowerPC:</h4>
236 dpavlin 2
237 dpavlin 20 PowerPC emulation is still in its beginning stages, but good enough
238     to run NetBSD/prep 2.1.
239 dpavlin 2
240 dpavlin 20 <p>Non-MIPS emulation modes use dynamic translation, but not recompilation
241     into native code. This makes it possible to run on any host platform.
242 dpavlin 6
243 dpavlin 2
244    
245    
246    
247     <p><br>
248     <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 2 several steps within a real CPU are not taken into account (eg. 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 12 <p>Caches are by default not emulated. In some cases, the existance of
258     caches is "faked" to let operating systems think that they are there.
259     (There is some old code for R2000/R3000 caches, but it has probably
260     suffered from bitrot by now.)
261 dpavlin 2
262 dpavlin 12 <p>The emulator is <i>not</i> timing-accurate. It can be run in a
263     "deterministic" mode, <tt><b>-D</b></tt>. The meaning of deterministic is
264     simply that running two emulations with the same settings will result in
265     identical runs. Obviously, this requires that no user interaction is
266     taking place, and that clock speeds are fixed with the <tt><b>-I</b></tt>
267     option. (Deterministic in this case does <i>not</i> mean that the
268     emulation will be identical to some actual real-world machine.)
269 dpavlin 2
270 dpavlin 20 <p><font color="#ff0000">(Oops/TODO: User interaction means <i>both</i>
271     input to the emulated program/OS, and interacting with the emulator
272     itself. Breaking into the debugger and then continuing execution may
273     affect when/how interrupts occur.)</font>
274 dpavlin 2
275    
276 dpavlin 6
277    
278 dpavlin 20
279    
280 dpavlin 2 <p><br>
281     <a name="emulmodes"></a>
282     <h3>Which machines does GXemul emulate?</h3>
283    
284 dpavlin 4 A few different machine types are emulated. The following machine types
285     are emulated well enough to run at least one "guest OS":
286 dpavlin 2
287     <p>
288     <ul>
289 dpavlin 14 <li><b><u>MIPS</u></b>
290     <ul>
291     <li><b>DECstation 5000/200</b>&nbsp;&nbsp;("3max")
292     <li><b>Acer Pica-61</b>&nbsp;&nbsp;(an ARC machine)
293     <li><b>NEC MobilePro 770, 780, 800, and 880</b>&nbsp;&nbsp;(HPCmips machines)
294     <li><b>Cobalt</b>
295 dpavlin 20 <li><b>Malta</b> (evbmips)
296 dpavlin 22 <li><b>SGI O2 ("IP32")</b> <font color="#0000e0">(<super>*</super>)</font>
297 dpavlin 14 </ul>
298     <p>
299     <li><b><u>ARM</u></b>
300     <ul>
301     <li><b>CATS</b>
302 dpavlin 22 <li><b>IQ80321</b> (evbarm)
303 dpavlin 14 </ul>
304 dpavlin 20 <p>
305     <li><b><u>PowerPC</u></b>
306     <ul>
307     <li><b>PReP (PowerPC Reference Platform)</b>
308     </ul>
309 dpavlin 2 </ul>
310    
311 dpavlin 22 <p><small><font color="#0000e0">(<super>*</super>)</font> =
312     Enough for root-on-nfs, but not for disk boot.)</small>
313    
314 dpavlin 10 <p>There is code in GXemul for emulation of many other machine types; the
315     degree to which these work range from almost being able to run a complete
316     OS, to almost completely unsupported (perhaps just enough support to
317     output a few boot messages via serial console).
318 dpavlin 2
319 dpavlin 10 <p>In addition to emulating real machines, there is also a "test-machine".
320     A test-machine consists of one or more CPUs and a few experimental devices
321     such as:
322 dpavlin 2
323     <p>
324     <ul>
325     <li>a console I/O device (putchar() and getchar()...)
326     <li>an inter-processor communication device, for SMP experiments
327     <li>a very simple linear framebuffer device (for graphics output)
328 dpavlin 12 <li>a simple SCSI disk controller
329     <li>a simple ethernet controller
330 dpavlin 2 </ul>
331    
332 dpavlin 10 <p>This mode is useful if you wish to run experimental code, but do not
333 dpavlin 2 wish to target any specific real-world machine type, for example for
334     educational purposes.
335    
336 dpavlin 10 <p>You can read more about these experimental devices <a
337     href="experiments.html#expdevices">here</a>.
338 dpavlin 2
339    
340    
341    
342    
343    
344     </body>
345     </html>

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