--- trunk/man/gxemul.1 2007/10/08 16:18:38 12 +++ trunk/man/gxemul.1 2007/10/08 16:19:37 22 @@ -1,6 +1,6 @@ -.\" $Id: gxemul.1,v 1.29 2005/08/10 15:51:09 debug Exp $ +.\" $Id: gxemul.1,v 1.49 2006/02/18 14:02:20 debug Exp $ .\" -.\" Copyright (C) 2004-2005 Anders Gavare. All rights reserved. +.\" Copyright (C) 2004-2006 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: @@ -29,7 +29,7 @@ .\" This is a minimal man page for GXemul. Process this file with .\" groff -man -Tascii gxemul.1 or nroff -man gxemul.1 .\" -.Dd AUGUST 2005 +.Dd FEBRUARY 2006 .Dt GXEMUL 1 .Os .Sh NAME @@ -41,33 +41,48 @@ .Op file Ar ... .Nm .Op general options -.Op Ar @configfile ... +.Ar @configfile .Nm .Op userland, other, and general options .Ar file Op Ar args ... .Sh DESCRIPTION .Nm -is an experimental instruction-level machine emulator. It can be used to -run binary code for MIPS-based machines, regardless of host -platform. Several emulation modes are available. For 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 -(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.) -.Pp -There are three ways to invoke the emulator. When emulating a -complete machine, settings can be entered directly on the command line, or -they can be read from a configuration file. 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. +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 inside the emulator as if they were running on a +real machine. +.Pp +The processor architecture best emulated by GXemul is MIPS, but other +architectures (ARM and PowerPC) are also partially emulated. +.Pp +MIPS processors are emulated using either a simple binary translation +layer (recompilation into native code), which is used on Alpha and i386 +hosts, or by traditional interpretation (very very slow, but works on any +host platform). +.Pp +Non-MIPS processors are emulated using a newer dynamic translation +system (called dyntrans in the rest of this man page). Performance is +somewhere between traditional interpretation and recompilation into native +code. However, the dynamic translation system used in GXemul does NOT +generate native code, and thus doesn't require platform-specific +back-ends. In plain English, this means that the dyntrans system works on +any host platform. +.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, ECOFF, +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 @@ -120,11 +135,15 @@ .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. +emulated code actually tries to do unaligned loads or stores. (This option +is only meaningful when emulating MIPS CPUs, when the host architecture is +Alpha or i386, and binary translation is enabled.) .It Fl B -Disable dynamic binary translation. By default, bintrans -will be turned on if the host+target architecture combination is -supported. +Disable native translation backends. By default, translation backends are +used if the host+target architecture combination is supported. Currently, +the only supported host architecture for the old bintrans system (used +when emulating MIPS processors) are Alpha and i386. The old bintrans +system will hopefully be removed some day. .It Fl C Ar x Try to emulate a specific CPU type, .Ar "x". @@ -152,23 +171,23 @@ Override the default geometry; use H heads and S sectors-per-track. (The number of cylinders is calculated automatically.) .It i -IDE. +IDE. (This is the default for most machine types.) .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). +SCSI. .It t Tape. .It 0-7 Force a specific ID number. .El .Pp -Unless otherwise specified, filenames ending with ".iso" 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.) +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 @@ -183,7 +202,9 @@ .It Fl i Display each instruction as it is being executed. .It Fl J -Disable some speed tricks. +Disable some speed tricks. For MIPS emulation, these are mostly +timing-related. For non-MIPS emulation (i.e. modes using dyntrans), +this flag disables the use of "instruction combinations". .It Fl j Ar n Set the name of the kernel to .Ar "n". @@ -203,15 +224,20 @@ .It Fl N Display nr of instructions/second average, at regular intervals. .It Fl n Ar nr -Set nr of CPUs (for SMP experiments). +Set nr of CPUs (for SMP experiments). Note: The emulator allocates quite a +lot of virtual memory for per-CPU translation tables. On 64-bit hosts, +this is normally not a problem. On 32-bit hosts, this can use up all +available virtual userspace memory. The solution is to either run the +emulator on a 64-bit host, or limit the number of emulated CPUs to a +reasonable number (say, less than 32). .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). +Set the boot argument (mostly useful for DEC, ARC, or SGI emulation). Default .Ar arg -for DEC is "-a", for ARC "-aN". +for DEC is "-a", for ARC/SGI it is "-aN", and for CATS it is "-A". .It Fl p Ar pc Add a breakpoint. (Remember to use the "0x" prefix for hex.) .It Fl Q @@ -230,17 +256,34 @@ .It Fl U Enable slow_serial_interrupts_hack_for_linux. .It Fl X -Use X11. +Use X11. This option enables graphical framebuffers. .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.) +Open up new xterms for emulated serial ports. The default behaviour is to +open up xterms when using configuration files, or if X11 is enabled. When +starting up a simple emulation session with settings directly on the +command line, and neither +.Fl X +nor +.Fl x +is used, then all output is confined to the terminal that +.Nm +started in. .It Fl Y Ar n Scale down framebuffer windows by .Ar n x .Ar n -times. +times. This option is useful when emulating a very large framebuffer, and +the actual display is of lower resolution. If +.Ar n +is negative, then there will be no scaledown, but emulation of certain +graphic controllers will be scaled up +by +.Ar -n +times instead. E.g. Using +.Ar -2 +with VGA text mode emulation will result in 80x25 character cells rendered +in a 1280x800 window, instead of the normal resolution of 640x400. .It Fl y Ar x Set max_random_cycles_per_chunk to .Ar x @@ -266,6 +309,13 @@ .Pp General options: .Bl -tag -width Ds +.It Fl c Ar cmd +Add +.Ar cmd +as a command to run before starting the simulation. A similar effect can +be achieved by using the +.Fl V +option, and entering the commands manually. .It Fl D Guarantee fully deterministic behavior. Normally, the emulator calls srandom() with a seed based on the current time at startup. When the @@ -289,11 +339,14 @@ .It Fl q Quiet mode; this suppresses startup messages. .It Fl s -Show opcode usage statistics after the simulation. +For MIPS emulation: Show opcode usage statistics after the simulation. +For non-MIPS emulation (i.e. using dyntrans): Save statistics to a file at +regular intervals of which physical addresses that were executed. .It Fl V Start up in the single-step debugger, paused. .It Fl v -Verbose debug messages. +Increase verbosity (show more debug messages). This option can be used +multiple times. .El .Pp Configuration file startup: @@ -340,19 +393,30 @@ 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. +The binary translation subsystem used for emulating MIPS processors is +really terrible, but it is less terrible than running without it. It will +be removed once the newer MIPS dyntrans emulation mode works well enough. .Pp Userland (syscall-only) emulation doesn't really work yet. .Pp +Emulation of MIPS CPUs is done differently from other emulation modes; the +documentation sometimes only reflects the way things work with MIPS +emulation, and it is incorrect when applied to e.g. ARM emulation. +.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 performance measurement. +is in general not cycle-accurate; it 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. +is not timing-accurate, i.e. clocks inside the emulator are in general +not at all synched with clocks in the real world. There are a few +exceptions to this rule (the mc146818 device tries to automagically +adjust emulated timer ticks to actual emulation speed). .Sh AUTHOR -Anders Gavare +GXemul is Copyright (C) 2003-2006 Anders Gavare .Pp -See http://gavare.se/gxemul/ for more information. +See http://gavare.se/gxemul/ for more information. For other Copyright +messages, see the corresponding parts of the source code and/or +documentation.