trunk/man/gxemul.1

.\" $Id: gxemul.1,v 1.33 2005/10/07 22:45:34 debug Exp $
.\"
.\" Copyright (C) 2004-2005  Anders Gavare.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\" 
.\" 
.\" This is a minimal man page for GXemul. Process this file with
.\"     groff -man -Tascii gxemul.1    or    nroff -man gxemul.1
.\"
.Dd OCTOBER 2005
.Dt GXEMUL 1
.Os
.Sh NAME
.Nm gxemul
.Nd an experimental machine emulator
.Sh SYNOPSIS
.Nm
.Op machine, other, and general options
.Op file Ar ...
.Nm
.Op general options
.Ar @configfile
.Nm
.Op userland, other, and general options
.Ar file Op Ar args ...
.Sh DESCRIPTION
.Nm
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.
.Pp
The processor architecture best emulated by GXemul is MIPS, but other
architectures are also partially emulated.
.Pp
There are three ways to invoke the emulator:
.Pp
1. When emulating a complete machine, configuration options can be entered
directly on the command line.
.Pp
2. Options can be read from a configuration file.
.Pp
3. When emulating a userland environment (syscall-only emulation, not
emulating complete machines), then the program name and its argument
should be given on the command line. (This mode doesn't really work yet.)
.Pp
The easiest way to use the emulator is to supply settings directly on the 
command line. The most important thing you need to supply is the
file argument. This is the name of a binary file (an ELF, a.out, COFF/ECOFF,
SREC, or a raw binary image) which you wish to run in the emulator. This file
might be an operating system kernel, or perhaps a ROM image file.
.Pp
If more than one filename is supplied, all files are loaded into memory, 
and the entry point (if available) is taken from the last file.
.Pp
Apart from the name of a binary file, it is also necessary to select
which specific emulation mode to use. For example, a MIPS-based machine
from DEC (a DECstation) is very different from a MIPS-based machine
from SGI. Use
.Nm
.Fl H
to get a list of available emulation modes.
.Pp
There are two exceptions to the normal invocation usage mentioned above.
The first is for DECstation emulation: if you have a bootable
DECstation harddisk or CDROM image, then just supplying the diskimage via 
the
.Fl d
option is sufficient. (The filename of the kernel can then be 
skipped, as the emulator runs the bootblocks from the diskimage directly and 
doesn't need the kernel as a separate file.)
The second is if you supply an ISO9660 CDROM disk image. You may then use 
the
.Fl j
option to indicate which file on the CDROM filesystem that should be 
loaded into emulated memory.
.Pp
Machine selection options:
.Bl -tag -width Ds
.It Fl E Ar t
Try to emulate machine type
.Ar "t".
This option is not always needed, if the
.Fl e
option uniquely selects a machine.
(Use
.Fl H
to get a list of types.)
.It Fl e Ar st
Try to emulate machine subtype
.Ar "st".
Use this together with
.Fl E .
(This option is not always needed, if a machine type has no subtypes.)
.El
.Pp
Other options:
.Bl -tag -width Ds
.It Fl A
Disable load/store alignment checks in some cases. This might give a small
increase in performance, but the emulator will not run correctly if the 
emulated code actually tries to do unaligned loads or stores.
.It Fl B
Disable dynamic binary translation. By default, bintrans
will be turned on if the host+target architecture combination is 
supported.
.It Fl C Ar x
Try to emulate a specific CPU type,
.Ar "x".
This overrides the default CPU type for the machine being emulated.
(Use
.Fl H
to get a list of available CPU types.)
.It Fl d Ar name
Add
.Ar name
as a disk image. By adding one or more modifier characters and then a
colon (":") as a prefix to
.Ar "name",
you can modify the way the disk image is treated. Available modifiers are:
.Bl -tag -width Ds
.It b
Specifies that this is a boot device.
.It c
CD-ROM.
.It d
DISK (this is the default).
.It f
FLOPPY.
.It gH;S;
Override the default geometry; use H heads and S sectors-per-track.
(The number of cylinders is calculated automatically.)
.It i
IDE.
.It r
Read-only (don't allow changes to be written to the file).
.It s
SCSI (this is the default for most machine types).
.It t
Tape.
.It 0-7
Force a specific ID number.
.El
.Pp
Unless otherwise specified, filenames ending with ".iso" or ".cdr" are 
assumed to be CDROM images. Most others are assumed to be disks. Depending
on which machine is being emulated, the default for disks can be either 
SCSI or IDE. Some disk images that are very small are assumed to be floppy 
disks. (If you are not happy with the way a disk image is detected, then 
you need to use explicit prefixes to force a specific type.)
.Pp
For floppies, the gH;S; prefix is ignored. Instead, the number of 
heads and cylinders are assumed to be 2 and 80, respectively, and the 
number of sectors per track is calculated automatically. (This works for 
720KB, 1.2MB, 1.44MB, and 2.88MB floppies.)
.It Fl I Ar x
Emulate clock interrupts at
.Ar x
Hz. (This affects emulated clock devices only, not actual runtime speed.
This disables automatic clock adjustments, which is otherwise turned on.)
(This option is probably only valid for DECstation emulation.)
.It Fl i
Display each instruction as it is being executed.
.It Fl J
Disable some speed tricks.
.It Fl j Ar n
Set the name of the kernel to
.Ar "n".
When booting from an ISO9660 filesystem, the emulator will try to boot 
using this file. (In some emulation modes, eg. DECstation, this name is passed 
along to the boot program. Useful names are "bsd" for OpenBSD/pmax, 
or "vmunix" for Ultrix.)
.It Fl M Ar m
Emulate
.Ar m
MBs of physical RAM. This overrides the default amount of RAM for the 
selected machine type.
.It Fl m Ar nr
Run at most
.Ar nr
instructions (on any cpu).
.It Fl N
Display nr of instructions/second average, at regular intervals.
.It Fl n Ar nr
Set nr of CPUs (for SMP experiments).
.It Fl O
Force a "netboot" (tftp instead of disk), even when a disk image is
present (for DECstation, SGI, and ARC emulation).
.It Fl o Ar arg
Set the boot argument (for DEC, ARC, or SGI emulation).
Default
.Ar arg
for DEC is "-a", for ARC "-aN".
.It Fl p Ar pc
Add a breakpoint. (Remember to use the "0x" prefix for hex.)
.It Fl Q
Disable the built-in PROM emulation. This is useful for running raw ROM
images from real machines.
.It Fl R
Use a random bootstrap cpu, instead of CPU nr 0. (For SMP experiments.)
.It Fl r
Dump register contents for every executed instruction.
.It Fl S
Initialize the emulated RAM to random data, instead of zeroes.
.It Fl T
Enter the single-step debugger on unimplemented memory accesses.
.It Fl t
Show a trace tree of all function calls being made.
.It Fl U
Enable slow_serial_interrupts_hack_for_linux.
.It Fl X
Use X11.
.It Fl x
Open up new xterms for emulated serial ports. (Default is to open up 
xterms when using configuration files, but not when starting an 
emulation with settings directly on the command line.)
.It Fl Y Ar n
Scale down framebuffer windows by
.Ar n
x
.Ar n
times.
.It Fl y Ar x
Set max_random_cycles_per_chunk to
.Ar x
(experimental).
.It Fl Z Ar n
Set the number of graphics cards, for emulating a dual-head or tripple-head
environment. (Only for DECstation emulation so far.)
.It Fl z Ar disp
Add
.Ar disp
as an X11 display to use for framebuffers.
.El
.Pp
Userland options:
.Bl -tag -width Ds
.It Fl u Ar emul-mode
Userland-only (syscall) emulation. (Use
.Fl H
to get a list of available emulation modes.) Some (but not all) of the
options listed under Other options above can also be used with userland
emulation.
.El
.Pp
General options:
.Bl -tag -width Ds
.It Fl D
Guarantee fully deterministic behavior. Normally, the emulator calls
srandom() with a seed based on the current time at startup. When the
.Fl D
option is used, the srandom() call is skipped, which should cause two 
subsequent invocations of the emulator to be identical, if all other 
settings are identical and no user input is taking place. (If this option 
is used, then
.Fl I
must also be used.)
.It Fl H
Display a list of available CPU types, machine types, and userland
emulation modes. (Most of these don't work. Please read the documentation
included in the
.Nm
distribution for details on which modes that actually work.)
.It Fl h
Display a list of all available command line options.
.It Fl K
Force the single-step debugger to be entered at the end of a simulation.
.It Fl q
Quiet mode; this suppresses startup messages.
.It Fl s
Show opcode usage statistics after the simulation.
.It Fl V
Start up in the single-step debugger, paused.
.It Fl v
Verbose debug messages.
.El
.Pp
Configuration file startup:
.Bl -tag -width Ds
.It @ Ar configfile
Start an emulation based on the contents of
.Ar "configfile".
.El
.Pp
For more information, please read the documentation in the doc/
subdirectory of the
.Nm
distribution.
.Sh EXAMPLES
The following command will start NetBSD/pmax on an emulated DECstation 
5000/200 (3MAX):
.Pp
.Dl "gxemul -e 3max -d nbsd_pmax.img"
.Pp
nbsd_pmax.img should be a raw disk image containing a bootable 
NetBSD/pmax filesystem.
.Pp
The following command will start an emulation session based on settings in 
the configuration file "mysession". The -v option tells gxemul to be
verbose.
.Pp
.Dl "gxemul -v @mysession"
.Pp
If you have compiled the small Hello World program mentioned in the
.Nm
documentation, the following command will start up an
emulated test machine in "paused" mode:
.Pp
.Dl "gxemul -E testmips -V hello_mips"
.Pp
(Paused mode means that you enter the interactive single-step debugger
directly at startup, instead of launching the Hello World program.)
.Pp
Please read the documentation for more details.
.Sh BUGS
There are many bugs. Some of the known bugs are listed in the BUGS
file in the
.Nm
source distribution, some are indirectly mentioned in the TODO file,
and some are mentioned in the source code itself.
.Pp
The binary translation subsystem is really terrible, but it is less
terrible than running without it.
.Pp
Userland (syscall-only) emulation doesn't really work yet.
.Pp
.Nm
does not simulate individual pipe-line stages or penalties caused by
branch-prediction misses or cache misses, so it cannot be used for
accurate simulation of any actual real-world processor.
.Pp
.Nm
is not timing-accurate.
.Sh AUTHOR
Anders Gavare <anders@gavare.se>
.Pp
See http://gavare.se/gxemul/ for more information.
1	dpavlin	14	.\" $Id: gxemul.1,v 1.33 2005/10/07 22:45:34 debug Exp $
2	dpavlin	2	.\"
3			.\" Copyright (C) 2004-2005 Anders Gavare. All rights reserved.
4			.\"
5			.\" Redistribution and use in source and binary forms, with or without
6			.\" modification, are permitted provided that the following conditions are met:
7			.\"
8			.\" 1. Redistributions of source code must retain the above copyright
9			.\" notice, this list of conditions and the following disclaimer.
10			.\" 2. Redistributions in binary form must reproduce the above copyright
11			.\" notice, this list of conditions and the following disclaimer in the
12			.\" documentation and/or other materials provided with the distribution.
13			.\" 3. The name of the author may not be used to endorse or promote products
14			.\" derived from this software without specific prior written permission.
15			.\"
16			.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17			.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18			.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19			.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20			.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21			.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22			.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23			.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24			.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25			.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26			.\" SUCH DAMAGE.
27			.\"
28			.\"
29			.\" This is a minimal man page for GXemul. Process this file with
30			.\" groff -man -Tascii gxemul.1 or nroff -man gxemul.1
31			.\"
32	dpavlin	14	.Dd OCTOBER 2005
33	dpavlin	2	.Dt GXEMUL 1
34			.Os
35			.Sh NAME
36			.Nm gxemul
37			.Nd an experimental machine emulator
38			.Sh SYNOPSIS
39			.Nm
40			.Op machine, other, and general options
41			.Op file Ar ...
42			.Nm
43			.Op general options
44	dpavlin	14	.Ar @configfile
45	dpavlin	2	.Nm
46			.Op userland, other, and general options
47			.Ar file Op Ar args ...
48			.Sh DESCRIPTION
49			.Nm
50	dpavlin	14	is an experimental instruction-level machine emulator. Several
51			emulation modes are available. In some modes, processors and surrounding
52			hardware components are emulated well enough to let unmodified operating
53			systems (e.g. NetBSD) run as if they were running on a real machine.
54	dpavlin	2	.Pp
55	dpavlin	14	The processor architecture best emulated by GXemul is MIPS, but other
56			architectures are also partially emulated.
57	dpavlin	12	.Pp
58	dpavlin	14	There are three ways to invoke the emulator:
59	dpavlin	2	.Pp
60	dpavlin	14	1. When emulating a complete machine, configuration options can be entered
61			directly on the command line.
62			.Pp
63			2. Options can be read from a configuration file.
64			.Pp
65			3. When emulating a userland environment (syscall-only emulation, not
66			emulating complete machines), then the program name and its argument
67			should be given on the command line. (This mode doesn't really work yet.)
68			.Pp
69	dpavlin	2	The easiest way to use the emulator is to supply settings directly on the
70			command line. The most important thing you need to supply is the
71	dpavlin	14	file argument. This is the name of a binary file (an ELF, a.out, COFF/ECOFF,
72	dpavlin	2	SREC, or a raw binary image) which you wish to run in the emulator. This file
73			might be an operating system kernel, or perhaps a ROM image file.
74			.Pp
75			If more than one filename is supplied, all files are loaded into memory,
76			and the entry point (if available) is taken from the last file.
77			.Pp
78			Apart from the name of a binary file, it is also necessary to select
79			which specific emulation mode to use. For example, a MIPS-based machine
80			from DEC (a DECstation) is very different from a MIPS-based machine
81			from SGI. Use
82			.Nm
83			.Fl H
84			to get a list of available emulation modes.
85			.Pp
86	dpavlin	6	There are two exceptions to the normal invocation usage mentioned above.
87			The first is for DECstation emulation: if you have a bootable
88	dpavlin	2	DECstation harddisk or CDROM image, then just supplying the diskimage via
89			the
90			.Fl d
91	dpavlin	6	option is sufficient. (The filename of the kernel can then be
92	dpavlin	2	skipped, as the emulator runs the bootblocks from the diskimage directly and
93			doesn't need the kernel as a separate file.)
94	dpavlin	6	The second is if you supply an ISO9660 CDROM disk image. You may then use
95			the
96			.Fl j
97			option to indicate which file on the CDROM filesystem that should be
98			loaded into emulated memory.
99	dpavlin	2	.Pp
100			Machine selection options:
101			.Bl -tag -width Ds
102			.It Fl E Ar t
103			Try to emulate machine type
104			.Ar "t".
105	dpavlin	12	This option is not always needed, if the
106			.Fl e
107			option uniquely selects a machine.
108	dpavlin	2	(Use
109			.Fl H
110			to get a list of types.)
111			.It Fl e Ar st
112			Try to emulate machine subtype
113			.Ar "st".
114			Use this together with
115			.Fl E .
116			(This option is not always needed, if a machine type has no subtypes.)
117			.El
118			.Pp
119			Other options:
120			.Bl -tag -width Ds
121	dpavlin	12	.It Fl A
122			Disable load/store alignment checks in some cases. This might give a small
123			increase in performance, but the emulator will not run correctly if the
124			emulated code actually tries to do unaligned loads or stores.
125	dpavlin	2	.It Fl B
126	dpavlin	10	Disable dynamic binary translation. By default, bintrans
127			will be turned on if the host+target architecture combination is
128			supported.
129	dpavlin	2	.It Fl C Ar x
130			Try to emulate a specific CPU type,
131			.Ar "x".
132			This overrides the default CPU type for the machine being emulated.
133			(Use
134			.Fl H
135			to get a list of available CPU types.)
136			.It Fl d Ar name
137			Add
138			.Ar name
139			as a disk image. By adding one or more modifier characters and then a
140			colon (":") as a prefix to
141			.Ar "name",
142	dpavlin	6	you can modify the way the disk image is treated. Available modifiers are:
143	dpavlin	2	.Bl -tag -width Ds
144			.It b
145			Specifies that this is a boot device.
146			.It c
147	dpavlin	4	CD-ROM.
148	dpavlin	2	.It d
149	dpavlin	4	DISK (this is the default).
150			.It f
151			FLOPPY.
152	dpavlin	6	.It gH;S;
153			Override the default geometry; use H heads and S sectors-per-track.
154			(The number of cylinders is calculated automatically.)
155	dpavlin	2	.It i
156	dpavlin	4	IDE.
157	dpavlin	2	.It r
158			Read-only (don't allow changes to be written to the file).
159	dpavlin	4	.It s
160			SCSI (this is the default for most machine types).
161	dpavlin	2	.It t
162	dpavlin	4	Tape.
163	dpavlin	2	.It 0-7
164	dpavlin	6	Force a specific ID number.
165	dpavlin	2	.El
166			.Pp
167	dpavlin	14	Unless otherwise specified, filenames ending with ".iso" or ".cdr" are
168			assumed to be CDROM images. Most others are assumed to be disks. Depending
169			on which machine is being emulated, the default for disks can be either
170			SCSI or IDE. Some disk images that are very small are assumed to be floppy
171			disks. (If you are not happy with the way a disk image is detected, then
172			you need to use explicit prefixes to force a specific type.)
173	dpavlin	6	.Pp
174			For floppies, the gH;S; prefix is ignored. Instead, the number of
175			heads and cylinders are assumed to be 2 and 80, respectively, and the
176			number of sectors per track is calculated automatically. (This works for
177			720KB, 1.2MB, 1.44MB, and 2.88MB floppies.)
178	dpavlin	2	.It Fl I Ar x
179			Emulate clock interrupts at
180			.Ar x
181			Hz. (This affects emulated clock devices only, not actual runtime speed.
182			This disables automatic clock adjustments, which is otherwise turned on.)
183			(This option is probably only valid for DECstation emulation.)
184			.It Fl i
185			Display each instruction as it is being executed.
186			.It Fl J
187			Disable some speed tricks.
188			.It Fl j Ar n
189			Set the name of the kernel to
190			.Ar "n".
191	dpavlin	10	When booting from an ISO9660 filesystem, the emulator will try to boot
192			using this file. (In some emulation modes, eg. DECstation, this name is passed
193	dpavlin	6	along to the boot program. Useful names are "bsd" for OpenBSD/pmax,
194			or "vmunix" for Ultrix.)
195	dpavlin	2	.It Fl M Ar m
196			Emulate
197			.Ar m
198			MBs of physical RAM. This overrides the default amount of RAM for the
199			selected machine type.
200			.It Fl m Ar nr
201			Run at most
202			.Ar nr
203			instructions (on any cpu).
204			.It Fl N
205			Display nr of instructions/second average, at regular intervals.
206			.It Fl n Ar nr
207			Set nr of CPUs (for SMP experiments).
208			.It Fl O
209			Force a "netboot" (tftp instead of disk), even when a disk image is
210			present (for DECstation, SGI, and ARC emulation).
211			.It Fl o Ar arg
212			Set the boot argument (for DEC, ARC, or SGI emulation).
213			Default
214			.Ar arg
215	dpavlin	6	for DEC is "-a", for ARC "-aN".
216	dpavlin	2	.It Fl p Ar pc
217	dpavlin	6	Add a breakpoint. (Remember to use the "0x" prefix for hex.)
218	dpavlin	2	.It Fl Q
219			Disable the built-in PROM emulation. This is useful for running raw ROM
220			images from real machines.
221			.It Fl R
222			Use a random bootstrap cpu, instead of CPU nr 0. (For SMP experiments.)
223			.It Fl r
224			Dump register contents for every executed instruction.
225			.It Fl S
226			Initialize the emulated RAM to random data, instead of zeroes.
227			.It Fl T
228			Enter the single-step debugger on unimplemented memory accesses.
229			.It Fl t
230			Show a trace tree of all function calls being made.
231			.It Fl U
232			Enable slow_serial_interrupts_hack_for_linux.
233			.It Fl X
234			Use X11.
235			.It Fl x
236			Open up new xterms for emulated serial ports. (Default is to open up
237			xterms when using configuration files, but not when starting an
238			emulation with settings directly on the command line.)
239			.It Fl Y Ar n
240			Scale down framebuffer windows by
241			.Ar n
242			x
243			.Ar n
244			times.
245			.It Fl y Ar x
246			Set max_random_cycles_per_chunk to
247			.Ar x
248			(experimental).
249			.It Fl Z Ar n
250			Set the number of graphics cards, for emulating a dual-head or tripple-head
251			environment. (Only for DECstation emulation so far.)
252			.It Fl z Ar disp
253			Add
254			.Ar disp
255			as an X11 display to use for framebuffers.
256			.El
257			.Pp
258			Userland options:
259			.Bl -tag -width Ds
260			.It Fl u Ar emul-mode
261			Userland-only (syscall) emulation. (Use
262			.Fl H
263			to get a list of available emulation modes.) Some (but not all) of the
264			options listed under Other options above can also be used with userland
265			emulation.
266			.El
267			.Pp
268			General options:
269			.Bl -tag -width Ds
270			.It Fl D
271	dpavlin	6	Guarantee fully deterministic behavior. Normally, the emulator calls
272	dpavlin	2	srandom() with a seed based on the current time at startup. When the
273			.Fl D
274			option is used, the srandom() call is skipped, which should cause two
275	dpavlin	6	subsequent invocations of the emulator to be identical, if all other
276			settings are identical and no user input is taking place. (If this option
277			is used, then
278	dpavlin	2	.Fl I
279			must also be used.)
280			.It Fl H
281			Display a list of available CPU types, machine types, and userland
282			emulation modes. (Most of these don't work. Please read the documentation
283			included in the
284			.Nm
285			distribution for details on which modes that actually work.)
286			.It Fl h
287			Display a list of all available command line options.
288			.It Fl K
289			Force the single-step debugger to be entered at the end of a simulation.
290			.It Fl q
291			Quiet mode; this suppresses startup messages.
292			.It Fl s
293			Show opcode usage statistics after the simulation.
294			.It Fl V
295			Start up in the single-step debugger, paused.
296			.It Fl v
297			Verbose debug messages.
298			.El
299			.Pp
300			Configuration file startup:
301			.Bl -tag -width Ds
302			.It @ Ar configfile
303			Start an emulation based on the contents of
304			.Ar "configfile".
305			.El
306			.Pp
307			For more information, please read the documentation in the doc/
308			subdirectory of the
309			.Nm
310			distribution.
311			.Sh EXAMPLES
312			The following command will start NetBSD/pmax on an emulated DECstation
313	dpavlin	10	5000/200 (3MAX):
314	dpavlin	2	.Pp
315	dpavlin	12	.Dl "gxemul -e 3max -d nbsd_pmax.img"
316	dpavlin	2	.Pp
317	dpavlin	10	nbsd_pmax.img should be a raw disk image containing a bootable
318	dpavlin	2	NetBSD/pmax filesystem.
319			.Pp
320			The following command will start an emulation session based on settings in
321			the configuration file "mysession". The -v option tells gxemul to be
322			verbose.
323			.Pp
324			.Dl "gxemul -v @mysession"
325			.Pp
326			If you have compiled the small Hello World program mentioned in the
327			.Nm
328			documentation, the following command will start up an
329			emulated test machine in "paused" mode:
330			.Pp
331			.Dl "gxemul -E testmips -V hello_mips"
332			.Pp
333			(Paused mode means that you enter the interactive single-step debugger
334			directly at startup, instead of launching the Hello World program.)
335			.Pp
336			Please read the documentation for more details.
337			.Sh BUGS
338			There are many bugs. Some of the known bugs are listed in the BUGS
339			file in the
340			.Nm
341	dpavlin	12	source distribution, some are indirectly mentioned in the TODO file,
342			and some are mentioned in the source code itself.
343	dpavlin	2	.Pp
344	dpavlin	10	The binary translation subsystem is really terrible, but it is less
345			terrible than running without it.
346	dpavlin	2	.Pp
347	dpavlin	12	Userland (syscall-only) emulation doesn't really work yet.
348			.Pp
349	dpavlin	2	.Nm
350			does not simulate individual pipe-line stages or penalties caused by
351	dpavlin	14	branch-prediction misses or cache misses, so it cannot be used for
352			accurate simulation of any actual real-world processor.
353	dpavlin	6	.Pp
354			.Nm
355			is not timing-accurate.
356	dpavlin	2	.Sh AUTHOR
357			Anders Gavare <anders@gavare.se>
358			.Pp
359			See http://gavare.se/gxemul/ for more information.