/[gxemul]/upstream/0.4.1/README
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Contents of /upstream/0.4.1/README

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Revision 29 - (show annotations)
Mon Oct 8 16:20:32 2007 UTC (12 years, 5 months ago) by dpavlin
File size: 3281 byte(s)
0.4.1
1 Gavare's eXperimental Emulator -- GXemul 0.4.1
2 ==================================================
3
4 Copyright (C) 2003-2006 Anders Gavare.
5
6
7 Overview -- What is GXemul?
8 -----------------------------
9
10 GXemul is an experimental instruction-level machine emulator. Several
11 emulation modes are available. In some modes, processors and surrounding
12 hardware components are emulated well enough to let unmodified operating
13 systems (e.g. NetBSD) run as if they were running on a real machine.
14
15 Processors (ARM, MIPS, PowerPC) are emulated using a kind of dynamic
16 translation system. Performance is somewhere between traditional
17 interpretation and recompilation into native code. However, the dynamic
18 translation system used in GXemul does not (currently) generate native
19 code, and thus does not require platform-specific back-ends. In plain
20 English, this means that the dyntrans system works on any host platform.
21
22 Possible uses of the emulator include:
23
24 o) educational purposes, e.g. to learn how to write code for MIPS
25
26 o) hobby operating system development; the emulator can be used as a
27 complement to testing your code on real hardware
28
29 o) running guest operating systems in a "sandboxed" environment
30
31 o) compiling your source code inside a guest operating system which you
32 otherwise would not have access to (e.g. various exotic ports of
33 NetBSD), to make sure that your source code is portable to those
34 platforms
35
36 o) simulating (ethernet) networks of computers running various
37 operating systems, to study their interaction with each other
38
39 o) debugging code in general
40
41 Use your imagination :-)
42
43
44 GXemul's limitations
45 --------------------
46
47 o) GXemul is not (in general) a cycle-accurate simulator, because it does
48 not simulate things smaller than an instruction. Pipe-line stalls,
49 instruction latency effects etc. are more or less completely ignored.
50
51 o) Hardware devices have been implemented in an ad-hoc and as-needed
52 manner, usually only enough to fool certain guest operating systems
53 (e.g. NetBSD) that the hardware devices exist and function well
54 enough for those guest operating systems to use them.
55
56 A consequence of this is that a machine mode may be implemented well
57 enough to run NetBSD for that machine mode, but other guest operating
58 systems may not run at all, or behave strangely.
59
60
61 Quick start
62 -----------
63
64 To compile, type './configure' and then 'make'. This should work on most
65 Unix-like systems. If it does not, then please mail me a bug report.
66
67 You might want to experiment with various CC and CFLAGS environment
68 variable settings, to get optimum performance.
69
70 If you are impatient, and want to try out running a guest operating system
71 inside GXemul, read this: doc/guestoses.html#netbsdcatsinstall
72
73 If you want to use GXemul for experimenting with code of your own,
74 then I suggest you compile a Hello World program according to the tips
75 listed here: doc/experiments.html#hello
76
77 Please read the rest of the documentation in the doc/ sub-directory for
78 more detailed information on how to use the emulator.
79
80
81 Feedback
82 --------
83
84 If you have found GXemul useful in some way, or feel like sending me
85 comments or feedback in general, then mail me at anders(at)gavare.se.
86

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