/[gxemul]/trunk/doc/intro.html
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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revision 12 by dpavlin, Mon Oct 8 16:18:38 2007 UTC revision 20 by dpavlin, Mon Oct 8 16:19:23 2007 UTC
# Line 10  Line 10 
10    
11  <!--  <!--
12    
13  $Id: intro.html,v 1.61 2005/08/16 05:15:24 debug Exp $  $Id: intro.html,v 1.66 2005/11/23 22:03:24 debug Exp $
14    
15  Copyright (C) 2003-2005  Anders Gavare.  All rights reserved.  Copyright (C) 2003-2005  Anders Gavare.  All rights reserved.
16    
# Line 64  SUCH DAMAGE. Line 64  SUCH DAMAGE.
64  <a name="overview"></a>  <a name="overview"></a>
65  <h3>Overview:</h3>  <h3>Overview:</h3>
66    
67  GXemul is an experimental instruction-level machine emulator. It can be  GXemul is an experimental instruction-level machine emulator. Several
68  used to run binary code for MIPS-based machines, regardless of host  emulation modes are available. In some modes, processors and surrounding
69  platform. Several emulation modes are available. For some modes,  hardware components are emulated well enough to let unmodified operating
70  processors and surrounding hardware components are emulated well enough to  systems (e.g. NetBSD) run as if they were running on a real machine.
71  let unmodified operating systems run as if they were running on a real  
72  machine.  <p>The processor architecture best emulated by GXemul is MIPS, but other
73    architectures such as ARM and PowerPC are also partially emulated.
 <p>(Non-MIPS emulation modes are also under development, but so far none  
 of those modes has reached the completeness required to run unmodified  
 operating systems.)  
74    
75  <p>Devices and CPUs are not simulated with 100% accuracy. They are only  <p>Devices and CPUs are not simulated with 100% accuracy. They are only
76  ``faked'' well enough to make operating systems (e.g. NetBSD) run without  ``faked'' well enough to allow guest operating systems run without
77  complaining too much. Still, the emulator could be of interest for  complaining too much. Still, the emulator could be of interest for
78  academic research and experiments, such as when learning how to write  academic research and experiments, such as when learning how to write
79  operating system code.  operating system code.
80    
81  <p>The emulator is written in C, does not depend on external libraries  <p>The emulator is written in C, does not depend on third-party libraries
82  (except X11, but that is optional), and should compile and run on most  (except X11, but that is optional), and should compile and run on most
83  Unix-like systems. If it doesn't, then that is a bug.  Unix-like systems.
84    
85  <p>The emulator contains code which tries to emulate the workings of CPUs  <p>The emulator contains code which tries to emulate the workings of CPUs
86  and surrounding hardware found in real machines, but it does not contain  and surrounding hardware found in real machines, but it does not contain
# Line 136  without source code. You need to check a Line 133  without source code. You need to check a
133  The "easiest way out" if you plan to redistribute code from GXemul is, of  The "easiest way out" if you plan to redistribute code from GXemul is, of
134  course, to let it remain open source and simply supply the source code.  course, to let it remain open source and simply supply the source code.
135    
136  <p>(If a stable release of GXemul is packaged into binary form, and it is  <p>(If a stable, unmodified release of GXemul is packaged into binary form,
137  obvious which version of GXemul was used to build the package, then it can  and it is clear which version of GXemul was used to build the package,
138  be argued that the source code is available, just not in that specific  then it can be argued that the source code is available, just not in that
139  package. Common sense should be used in this case, and not pedanticism.)  specific package. Common sense should be used in this case, and not
140    pedanticism.)
141    
142    
143    
# Line 162  mail me a bug report. Line 159  mail me a bug report.
159    
160  <p>The emulator's performance is highly dependent on both runtime settings  <p>The emulator's performance is highly dependent on both runtime settings
161  and on compiler settings, so you might want to experiment with different  and on compiler settings, so you might want to experiment with different
162  CC and CFLAGS environment variable values. For example, on a modern PC,  CC and CFLAGS environment variable values. For example, on an AMD Athlon
163  you could try the following:  host, you might want to try setting <tt>CFLAGS</tt> to <tt>-march=athlon
164  <p><pre>  -O3</tt> before running <tt>configure</tt>.
         $ <b>CFLAGS="-mcpu=pentium4 -O3" ./configure</b>  
         $ <b>make</b>  
 </pre>  
165    
166    
167    
# Line 225  their original meaning in those xterm wi Line 219  their original meaning in those xterm wi
219  Emulation of R4000, which is a 64-bit CPU, was my initial goal.  Emulation of R4000, which is a 64-bit CPU, was my initial goal.
220  R2000/R3000-like CPUs (32-bit), R1x000, and generic MIPS32/MIPS64-style  R2000/R3000-like CPUs (32-bit), R1x000, and generic MIPS32/MIPS64-style
221  CPUs are also emulated, and are hopefully almost as stable as the R4000  CPUs are also emulated, and are hopefully almost as stable as the R4000
222  emulation.  emulation. Several guest operating systems for MIPS can run inside
223    the emulator.
224    
225  <p>I have written an experimental dynamic binary translation subsystem.  <p>(For MIPS emulation, I have written an experimental dynamic binary
226  This gives higher total performance than interpreting one instruction at a  translation subsystem, for Alpha and i386 hosts. This gives higher total
227  time and executing it. (If you wish to disable bintrans, add <b>-B</b> to  performance than interpreting one instruction at a time and executing it.
228  the command line.)  If you wish to disable bintrans, add <b>-B</b> to the command line.)
229    
230    <h4>ARM:</h4>
231    
232  <h4>Other CPU types:</h4>  ARM emulation is good enough to run NetBSD/cats 2.1 and OpenBSD/cats 3.8,
233    but it is not as tested or fine-tuned as the MIPS emulation mode.
234    
235  Some other CPU architectures can also be partially emulated. These are not  <h4>PowerPC:</h4>
 working well enough yet to run guest operating systems.  
236    
237    PowerPC emulation is still in its beginning stages, but good enough
238    to run NetBSD/prep 2.1.
239    
240    <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    
243    
244    
# Line 266  taking place, and that clock speeds are Line 267  taking place, and that clock speeds are
267  option. (Deterministic in this case does <i>not</i> mean that the  option. (Deterministic in this case does <i>not</i> mean that the
268  emulation will be identical to some actual real-world machine.)  emulation will be identical to some actual real-world machine.)
269    
270    <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    
275    
276    
277    
278    
# Line 279  are emulated well enough to run at least Line 286  are emulated well enough to run at least
286    
287  <p>  <p>
288  <ul>  <ul>
289    <li><b>DECstation 5000/200</b>&nbsp;&nbsp;("3max")    <li><b><u>MIPS</u></b>
290          <br>Serial controller (including keyboard and mouse), ethernet,    <ul>
291          SCSI, and graphical framebuffers.      <li><b>DECstation 5000/200</b>&nbsp;&nbsp;("3max")
292        <p>
293        <li><b>Acer Pica-61</b>&nbsp;&nbsp;(an ARC machine)
294        <p>
295        <li><b>NEC MobilePro 770, 780, 800, and 880</b>&nbsp;&nbsp;(HPCmips machines)
296        <p>
297        <li><b>Cobalt</b>
298        <p>
299        <li><b>Malta</b> (evbmips)
300        <p>
301        <li><b>SGI O2 ("IP32")</b>
302            <br><small>(Enough for root-on-nfs, but not for disk boot.)</small>
303      </ul>
304    <p>    <p>
305    <li><b>Acer Pica-61</b>&nbsp;&nbsp;(an ARC machine)    <li><b><u>ARM</u></b>
306          <br>Serial controller, "VGA" text console, and SCSI.    <ul>
307        <li><b>CATS</b>
308      </ul>
309    <p>    <p>
310    <li><b>NEC MobilePro 770, 780, 800, and 880</b>&nbsp;&nbsp;(HPCmips machines)    <li><b><u>PowerPC</u></b>
311          <br>Framebuffer, keyboard, and a PCMCIA IDE controller.    <ul>
312    <p>      <li><b>PReP (PowerPC Reference Platform)</b>
313    <li><b>Cobalt</b>    </ul>
         <br>Serial controller and PCI IDE.  
   <p>  
   <li><b>Malta (evbmips)</b>  
         <br>Serial controller and PCI IDE.  
   <p>  
   <li><b>SGI O2 ("IP32")</b>  
         <br>Serial controller and ethernet.&nbsp;&nbsp;<small>(Enough for  
         root-on-nfs, but not for disk boot.)</small>  
314  </ul>  </ul>
315    
316  <p>There is code in GXemul for emulation of many other machine types; the  <p>There is code in GXemul for emulation of many other machine types; the
# Line 430  interacted with similar to a real machin Line 443  interacted with similar to a real machin
443            <td></td>            <td></td>
444          </tr>          </tr>
445    
446            <tr><td height="10"></td></tr>
447    
448            <tr>
449              <td></td>
450              <td align="center"><a href="20051007-netbsd-cats-installed.png"><img src="20051007-netbsd-cats-installed_small.png"></a></td>
451              <td></td>
452              <td><a href="http://www.netbsd.org/Ports/cats/">NetBSD/cats</a>
453                    <br>CATS</td>
454              <td></td>
455              <td align="center"><a href="20051007-openbsd-cats-installed.png"><img src="20051007-openbsd-cats-installed_small.png"></a></td>
456              <td></td>
457              <td><a href="http://www.openbsd.org/cats.html">OpenBSD/cats</a>
458                    <br>CATS</td>
459              <td></td>
460            </tr>
461    
462            <tr><td height="10"></td></tr>
463    
464            <tr>
465              <td></td>
466              <td align="center"><a href="20051123-netbsd-prep.png"><img src="20051123-netbsd-prep_small.png"></a></td>
467              <td></td>
468              <td><a href="http://www.netbsd.org/Ports/prep/">NetBSD/prep</a>
469                    <br>PReP</td>
470              <td></td>
471            </tr>
472    
473  </table></center>  </table></center>
474    
475    
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