Contents of /upstream/20070918/README



          --------------------------------------------------------
            Gavare's eXperimental Emulator   --   GXemul 0.4.6.1
          --------------------------------------------------------


Copyright (C) 2003-2007  Anders Gavare


Overview  --  What is GXemul?
-----------------------------

GXemul is a framework for full-system computer architecture emulation. 
Several processor architectures and machine types have been implemented. 
It is working well enough to allow unmodified "guest" operating systems to 
run inside the emulator, as if they were running on real hardware.

The emulator emulates (networks of) real machines. The machines may 
consist of ARM, MIPS, PowerPC, and SuperH processors, and various 
surrounding hardware components such as framebuffers, busses, interrupt 
controllers, ethernet controllers, disk controllers, and serial port 
controllers.

GXemul, including the dynamic translation system, is implemented in 
portable C, which means that the emulator will run on practically any host 
architecture.

The documentation lists the machines and guest operating systems that can 
be regarded as "working" in GXemul. The best working guest operating 
systems are probably NetBSD/pmax and NetBSD/cats.

Possible uses of GXemul include:

 o)  running guest operating systems in a "sandboxed" environment

 o)  compiling your source code inside a guest operating system which you
     otherwise would not have access to (e.g. various exotic ports of
     NetBSD), to make sure that your source code is portable to those
     platforms

 o)  educational purposes, e.g. to learn how to write code for MIPS

 o)  hobby operating system development; the emulator can be used as a
     complement to testing your code on real hardware

 o)  simulating (ethernet) networks of computers running various
     operating systems, to study their interaction with each other

 o)  debugging code in general

Use your imagination :-)


GXemul's limitations
--------------------

 o)  GXemul is not a cycle-accurate simulator, because it does not simulate
     things smaller than an instruction. Pipe-line stalls, instruction latency
     effects etc. are more or less completely ignored.

 o)  Hardware devices have been implemented in an ad-hoc and as-needed manner,
     usually only enough to fool certain guest operating systems, e.g. NetBSD,
     that the hardware devices exist and function well enough for those guest
     operating systems to use them.

     (A consequence of this is that a machine mode may be implemented well
     enough to run NetBSD for that machine mode, but other guest operating
     systems may not run at all, or behave strangely.)


Quick start
-----------

To compile, type './configure' and then 'make'. This should work on most
Unix-like systems. If it does not, then please mail me a bug report.

You might want to experiment with various CC and CFLAGS environment
variable settings, to get optimum performance.

If you are impatient, and want to try out running a guest operating system 
inside GXemul, read this:  doc/guestoses.html#netbsdpmaxinstall

If you want to use GXemul for experimenting with code of your own, 
then I suggest you compile a Hello World program according to the tips 
listed here:  doc/experiments.html#hello

Please read the rest of the documentation in the doc/ sub-directory for
more detailed information on how to use the emulator.


Feedback
--------

If you have found GXemul useful in some way, or feel like sending me
comments or feedback in general, then mail me at anders(at)gavare.se.

1
2
3	--------------------------------------------------------
4	Gavare's eXperimental Emulator -- GXemul 0.4.6.1
5	--------------------------------------------------------
6
7
8	Copyright (C) 2003-2007 Anders Gavare
9
10
11
12	Overview -- What is GXemul?
13	-----------------------------
14
15	GXemul is a framework for full-system computer architecture emulation.
16	Several processor architectures and machine types have been implemented.
17	It is working well enough to allow unmodified "guest" operating systems to
18	run inside the emulator, as if they were running on real hardware.
19
20	The emulator emulates (networks of) real machines. The machines may
21	consist of ARM, MIPS, PowerPC, and SuperH processors, and various
22	surrounding hardware components such as framebuffers, busses, interrupt
23	controllers, ethernet controllers, disk controllers, and serial port
24	controllers.
25
26	GXemul, including the dynamic translation system, is implemented in
27	portable C, which means that the emulator will run on practically any host
28	architecture.
29
30	The documentation lists the machines and guest operating systems that can
31	be regarded as "working" in GXemul. The best working guest operating
32	systems are probably NetBSD/pmax and NetBSD/cats.
33
34	Possible uses of GXemul include:
35
36	o) running guest operating systems in a "sandboxed" environment
37
38	o) compiling your source code inside a guest operating system which you
39	otherwise would not have access to (e.g. various exotic ports of
40	NetBSD), to make sure that your source code is portable to those
41	platforms
42
43	o) educational purposes, e.g. to learn how to write code for MIPS
44
45	o) hobby operating system development; the emulator can be used as a
46	complement to testing your code on real hardware
47
48	o) simulating (ethernet) networks of computers running various
49	operating systems, to study their interaction with each other
50
51	o) debugging code in general
52
53	Use your imagination :-)
54
55
56
57	GXemul's limitations
58	--------------------
59
60	o) GXemul is not a cycle-accurate simulator, because it does not simulate
61	things smaller than an instruction. Pipe-line stalls, instruction latency
62	effects etc. are more or less completely ignored.
63
64	o) Hardware devices have been implemented in an ad-hoc and as-needed manner,
65	usually only enough to fool certain guest operating systems, e.g. NetBSD,
66	that the hardware devices exist and function well enough for those guest
67	operating systems to use them.
68
69	(A consequence of this is that a machine mode may be implemented well
70	enough to run NetBSD for that machine mode, but other guest operating
71	systems may not run at all, or behave strangely.)
72
73
74
75	Quick start
76	-----------
77
78	To compile, type './configure' and then 'make'. This should work on most
79	Unix-like systems. If it does not, then please mail me a bug report.
80
81	You might want to experiment with various CC and CFLAGS environment
82	variable settings, to get optimum performance.
83
84	If you are impatient, and want to try out running a guest operating system
85	inside GXemul, read this: doc/guestoses.html#netbsdpmaxinstall
86
87	If you want to use GXemul for experimenting with code of your own,
88	then I suggest you compile a Hello World program according to the tips
89	listed here: doc/experiments.html#hello
90
91	Please read the rest of the documentation in the doc/ sub-directory for
92	more detailed information on how to use the emulator.
93
94
95
96	Feedback
97	--------
98
99	If you have found GXemul useful in some way, or feel like sending me
100	comments or feedback in general, then mail me at anders(at)gavare.se.
101