/[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 31 by dpavlin,
Mon Oct  8 16:20:40 2007 UTC
+revision 32 by dpavlin,
Mon Oct  8 16:20:58 2007 UTC
 Line 10
  <!--
- $Id: intro.html,v 1.90 2006/08/14 17:45:47 debug Exp $
+ $Id: intro.html,v 1.100 2006/11/04 06:40:20 debug Exp $
  Copyright (C) 2003-2006  Anders Gavare.  All rights reserved.
 Line 73 
 emulation modes are available. In some m
  hardware components are emulated well enough to let unmodified operating
  systems (e.g. NetBSD) run as if they were running on a real machine.
- <p>Devices and processors (ARM, MIPS, PowerPC) are not simulated with 100%
+ <p>Devices and processors are not simulated with 100% accuracy. They are
- accuracy. They are only ``faked'' well enough to allow guest operating
+ only ``faked'' well enough to allow guest operating systems to run without
- systems run without complaining too much. Still, the emulator could be of
+ complaining too much. Still, the emulator could be of interest for
- interest for academic research and experiments, such as when learning how
+ academic research and experiments, such as when learning how to write
- to write operating system code.
+ operating system code.
  <p>The emulator is written in C, does not depend on third-party libraries,
  and should compile and run on most 64-bit and 32-bit Unix-like systems.
 Line 98 
 disk image, then it is sometimes possibl
  image. (This works for example with DECstation emulation, or when booting
  from ISO9660 CDROM images.)
+ <p>Thanks to (in no specific order) Joachim Buss, Olivier Houchard, Juli
+ Mallett, Juan Romero Pardines, Alec Voropay, Göran Weinholt, Alexander
+ Yurchenko, and everyone else who has provided me with feedback.
-Line 213 
 their original meaning in those xterm wi
+Line 216 
 their original meaning in those xterm wi
  <h3>Which processor architectures does GXemul emulate?</h3>
  The architectures that are emulated well enough to let at least one
- guest operating system run (per architecture) are ARM, MIPS, and
+ guest operating system run (per architecture) are ARM, MIPS, PowerPC,
- PowerPC.
+ and SuperH.
-Line 224 
 PowerPC.
+Line 228 
 PowerPC.
  <a name="hosts"></a>
  <h3>Which host architectures are supported?</h3>
- As of release 0.4.0 of GXemul, the old binary translation subsystem, which
+ GXemul should compile and run on any modern host architecture (64-bit or
- was used for emulation of MIPS processors on Alpha and i386 hosts, has
+-bit word-length).
- been removed. The current dynamic translation subsystem should work on any
- host.
+ <p>(The dynamic translation engine translates into an intermediate
+ representation, but not currently into native code. This means that there
+ is no need for per-host architecture backend code.)
-Line 424 
 translations are invalidated, and replac
+Line 430 
 translations are invalidated, and replac
  (similar to what is used in high-performance emulators such as QEMU),
  as long as that generated code abides to the C ABI on the host, but
  for now I wanted to make sure that GXemul works without such native
- code back-ends. For this reason, as of release 0.4.0, GXemul is
+ code back-ends. For this reason, since release 0.4.0, GXemul is
  completely free of native code back-ends.
-Line 446 
 emulator.
+Line 452 
 emulator.
  operating systems think that they are there, but for all practical
  purposes, these caches are non-working.
- <p>The emulator is <i>not</i> timing-accurate. It can be run in a
+ <p>The emulator is in general <i>not</i> timing-accurate, neither at the
- "deterministic" mode, <tt><b>-D</b></tt>. The meaning of deterministic is
+ instruction level nor on any higher level. An attempt is made to let
- simply that running two emulations with the same settings will result in
+ emulated clocks run at the same speed as the host (i.e. an emulated timer
- identical runs. Obviously, this requires that no user interaction is
+ running at 100 Hz will interrupt around 100 times per real second), but
- taking place, and that clock speeds are fixed with the <tt><b>-I</b></tt>
+ since the host speed may vary, e.g. because of other running processes,
- option. (Deterministic in this case does <i>not</i> mean that the
+ there is no guarantee as to how many instructions will be executed in
- emulation will be identical to some actual real-world machine.)
+ each of these 100 Hz cycles.
- <p>(Note that user interaction means <i>both</i> input to the emulated
+ <p>If the host is very slow, the emulated clocks might even lag behind
- program/OS, and interaction with the emulator's debugger. Breaking into the
+ the real-world clock.
- debugger and then continuing execution may affect when/how interrupts
- occur.)
-Line 489 
 are emulated well enough to run at least
+Line 493 
 are emulated well enough to run at least
          <a href="guestoses.html#declinux">Linux/DECstation</a>,
          <a href="guestoses.html#sprite">Sprite</a>)
      <li><b>Acer Pica-61</b> (<a href="guestoses.html#netbsdarcinstall">NetBSD/arc</a>)
-     <li><b>NEC MobilePro 770, 780, 800, and 880</b> (<a href="guestoses.html#netbsdhpcmipsinstall">NetBSD/hpcmips</a>)
+     <li><b>NEC MobilePro 770, 780, 800, 880</b> (<a href="guestoses.html#netbsdhpcmipsinstall">NetBSD/hpcmips</a>)
      <li><b>Cobalt</b> (<a href="guestoses.html#netbsdcobaltinstall">NetBSD/cobalt</a>)
      <li><b>Malta</b> (<a href="guestoses.html#netbsdevbmipsinstall">NetBSD/evbmips</a>)
      <li><b>Algorithmics P5064</b> (<a href="guestoses.html#netbsdalgorinstall">NetBSD/algor</a>)
-     <li><b>SGI O2 (aka IP32)</b> <font color="#0000e0">(<super>*</super>)</font>
+     <li><b>SGI O2 (aka IP32)</b> <font color="#0000e0">(<super>*1</super>)</font>
          (<a href="guestoses.html#netbsdsgimips">NetBSD/sgi</a>)
    </ul>
    <p>
-Line 501 
 are emulated well enough to run at least
+Line 505 
 are emulated well enough to run at least
    <ul>
      <li><b>IBM 6050/6070 (PReP, PowerPC Reference Platform)</b> (<a href="guestoses.html#netbsdprepinstall">NetBSD/prep</a>)
    </ul>
+   <p>
+   <li><b><u>SuperH</u></b>
+   <ul>
+     <li><b>Sega Dreamcast</b>
+         <font color="#0000e0">(<super>*2</super>)</font>
+         (<a href="guestoses.html#netbsddreamcast">NetBSD/dreamcast</a>)
+   </ul>
  </ul>
- <p><small><font color="#0000e0">(<super>*</super>)</font> =
+ <p>
- Enough for root-on-nfs, but not for disk boot.)</small>
+ <small><font color="#0000e0">(<super>*1</super>)</font> =
+ Enough for root-on-nfs, but not for disk boot.</small>
+ <br><small><font color="#0000e0">(<super>*2</super>)</font> =
+ Only enough to reach ramdisk userland; no root-on-nfs yet.</small>
  <p>There is code in GXemul for emulation of many other machine types; the
  degree to which these work range from almost being able to run a complete
-Line 520 
 such as:
+Line 534 
 such as:
    <li>a console I/O device (putchar() and getchar()...)
    <li>an inter-processor communication device, for SMP experiments
    <li>a very simple linear framebuffer device (for graphics output)
-   <li>a simple SCSI disk controller
+   <li>a simple disk controller
    <li>a simple ethernet controller
+   <li>a real-time clock device
  </ul>
  <p>This mode is useful if you wish to run experimental code, but do not

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