- PSIM
+ PSIM - model of a PowerPC platform
-Copyright (C) 1994-1995, Andrew Cagney <cagney@highland.com.au>
+ Copyright (C) 1994-1995, Andrew Cagney <cagney@highland.com.au>.
-This directory contains the program PSIM that models the PowerPC (tm -
-IBM) architecture. It can be run either standalone (psim or run) or
-used as part of GDB.
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-KNOWN FEATURES:
+This directory contains the program PSIM that implements a model of a
+PowerPC platform. PSIM can either be built standalone or as part of
+the debugger GDB.
-SMP: It is possible to configure this simulator so that it implements
-a restricted model of a Symetric Multi-Processor architecture. It is
-important to note that the SMP model has limitations. In particular,
-the PowerPC's load word and reserve (etc) instructions do not model
-the behavour defined in the Architecture manual. People intending to
-use this feature should read the code implementing those instructions.
-ENDIAN SUPORT: Pure big, pure little and PowerPC little endian (xor
-endian) models are suported.
+What is PSIM?
-UIEA, VEA and OEA: The PowerPC architecture defines three levels of
-the PowerPC architecture. This simulator, to a reasonable degree, is
-capable of modeling all three. That is the User Instruction Set
-Architecture, the Virtual Environment Architecture and finally the
-Operating Environment Architecture.
+ PSIM is an ANSI C program that models a PowerPC platform.
+ The platform it implements can vary from:
-HARDWARE DEVICE TREE: In the OEA, the model of the target machines
-hardware is built from a tree of devices (bit like Open Boot).
-Included in this is the ability to model bus hierachies and
-runtime-configurable devices (eg PCI).
+ o A user program environment (UEA) complete
+ with emulated system calls
-OS EMULATION: Suport for os/firmware emulations (system or rom-calls)
-is included. At present limited implemtations of two emulations are
-included:NetBSD (UEA model) and OpenBoot (OEA model).
+ to
-PEDANTIC VEA MEMORY MODEL: In VEA/UEA NetBSD simulations, this model
-implements the break (brk, sbrk) system calls. Further, the user
-model has very strict memory access controls. User programs can not
-assume that they can stray off the end of valid memory areas. This
-model defines valid memory addresses in strict accordance to the
-executable and does not page allign their values. At first this was a
-bug but since then has turned up several problems in user code so it
-is now described as a feature.
+ o A hardware platform with several processors
+ interacting with each other and modeled hardware.
-PERFORMANCE MONITORING: This simulation is able to monitor things such
-as cpu/io read/writes and register allocation.
-PERFORMANCE: In its default configuration PSIM is configured so that
-it will compile fast and run slow. Through the enabling of more
-agressive compile options (and the disabling of unwanted features) the
-build can be changed to compile slow and run fast.
+What motivated PSIM?
-FLOATING POINT: Preliminary suport for floating point is included.
-Real kernels don't need floating point.
+ As an idea, psim was first discussed seriously during mid
+ 1994. At that time its main objectives were:
-BUILDING PSIM:
+ o good performance
-To build PSIM you will need the following:
+ Many simulators loose out by only providing
+ a binary interface to the internals. This
+ inteface eventually becomming a bottle neck
+ in the simulators performance.
+
+ It was intended that PSIM would avoid this
+ problem by giving the user access to the
+ full source code.
+
+ Further, by exploiting the power of modern
+ compilers it was hoped that PSIM would achieve
+ good performance with out having to compromize
+ its internal design.
+
+
+ o practical portability
+
+ Rather than try to be portable to every
+ C compiler on every platform, it was decided
+ that PSIM would restrict its self to suporting
+ ANSI compilers that included the extension
+ of a long long type.
+
+ GCC is one such compiler, consequenly PSIM
+ should be portable to any machine running GCC.
+
+
+ o flexability in its design
+
+ PSIM should allow the user to select the
+ features required and customize the build
+ accordingly. By having the source code,
+ the compler is able to eliminate any un
+ used features of the simulator.
+
+ After all, let the compiler do the work.
+
+
+ o SMP
+
+ A model that allowed the simulation of
+ SMP platforms with out the large overhead
+ often encountered with such models.
+
+
+ PSIM achieves each of these objectives.
+
+
+Who would be interested in PSIM?
+
+ o the curious
+
+ Using psim, gdb, gcc and binutils the curious
+ user can contruct an environment that allows
+ them to play with PowerPC user programs with out
+ the need for real hardware.
+
+
+ o the analyst
+
+ PSIM includes many (contributed) monitoring
+ features which (unlike many other simulators)
+ do not come with a great penalty in performance.
+
+ Thus the performance analyst is able to use
+ this simulator to model the inpact of changes
+ to the system they are analysing. Be that
+ system a compiler or real hardware platform.
+
+ If PSIM doesn't monitor a components of interest,
+ the source code is freely available, and hence
+ there is no hinderance to changing things
+ to meet a specific analysts needs.
+
+
+ o the serious SW developer
+
+ PSIM models all three levels of the PowerPC
+ Architecture: UEA, VEA and OEA. Further,
+ the internal design is such that PSIM can
+ be extended to suport additional
+ development requirements. Such requirements
+ might include (for the UEA) a new Operating
+ System emulation through to (for the OEA)
+ a model of a different hardware platform.
+
+
+What features does PSIM have?
+
+
+ Monitoring and modeling
+
+ PSIM includes (thanks to Michael Meissner)
+ a detailed model of the various PowerPC
+ implementations schedulers.
+
+
+ SMP
+
+ The PowerPC ISA defines SMP synchronizing instructions
+ this simulator models a limited subset of their
+ behavor. Consequently, if you limit code to the
+ use the modeled behavour, PSIM can be used to
+ model SMP PowerPC platforms.
+
+ People intending to use this system should study
+ the code implementing the lwarx etc instructions.
+
+ ENDIAN SUPORT
+
+ PSIM implements all of Big-endian, little-endian
+ and PowerPC little endian (XOR endian).
+
+ ISA models
+
+ PSIM includes a model of UEA, VEA and OEA. This
+ inclues the time base registers (VEA) and HTAB
+ and BATS (OEA).
+
+ In addition, a preliminary model of the 64 bit
+ PowerPC architecture is included.
+
+ Hardware
+
+ PSIM's internals are based around the concept
+ of a Device Tree. This tree intentionaly
+ resembles that of the Device Tree found in
+ OpenBoot firmware. Psim is flexable enough
+ to allow the user to fully configure the
+ actual hardware model from a device tree
+ specification taken from a file.
+
+ PSIM also contains several built in device
+ trees.
+
+ Emulation
+
+ PSIM is able (UEA) to emulate UNIX calls
+ based on NetBSD abi through to (preliminary)
+ the ROM rom calls found in common firmware
+ (OpenBoot and BUGAPI).
+
+ floating point
+
+ Preliminary suport for floating point is included.
+ Real kernels don't need floating point.
+
+
+Can PSIM model a CHRP a.k.a. PowerPC Platform machine?
+
+ No. but that is now one of its main objectives. (Did you notice
+ it was written PowerPC Platform instead of PowerPC platform?).
+
+
+How do I build PSIM?
+
+ To build PSIM you will need the following:
gdb-4.15.tar.gz From your favorite GNU ftp site.
I've also tested psim-951016 with
empty files.
-Since PSIM is still being developed, from time to time, further psim
-snap shots are occasionally made available. These snapshots may or
-may not work with GDB-4.15. Several of the more significant snap
-shots are:
-
- ftp://ftp.ci.com.au/pub/clayton/psim-951215.tar.gz
+ Since PSIM is still being developed, from time to time, to meet
+ a specific analysts needsfurther psim snap shots are occasionally
+ made available. These snapshots may or may not work with GDB-4.15.
+ Several of the more recent snapshots are:
- A dangerous snap shot
+ ftp://ftp.ci.com.au/pub/clayton/psim-951218.tar.gz
Hopefully merges in Michael stuff
with mine, adds multiple emulations
PowerPC's register and bus architectures.
-Procedure:
+ ftp://ftp.ci.com.au/pub/clayton/psim-test-951218.tar.gz
+
+ Prebuilt test programs for PSIM.
+ Includes examples of UEA, VEA and
+ OEA code.
+ Requires gcc-2.7.2 and binutils-2.6
+ to rebuild.
+
-0. A starting point
+ Procedure:
+
+ 0. A starting point
$ ls -1
gdb-4.15+psim-951016.diff.gz
psim-test-951016.tar.gz
-1. Unpack gdb
+ 1. Unpack gdb
$ gunzip < gdb-4.15.tar.gz | tar xf -
-2. Change to the gdb directory, apply the psim patches and unpack
- the psim files.
+ 2. Change to the gdb directory, apply the psim patches and unpack
+ the psim files.
$ cd gdb-4.15
$ gunzip < ../gdb-4.15+psim-951016.tar.gz | tar xvf -
-3. Configure gdb
+ 3. Configure gdb
$ more gdb/README
- then something like (I assume SH):
+ then something like (I assume SH):
$ CC=gcc ./configure --target=powerpc-unknown-eabisim
- eabisim is needed as by default (because PSIM needs GCC) the
- simulator is not built.
+ eabisim is needed as by default (because PSIM needs GCC) the
+ simulator is not built.
-4. Build
+ 4. Build
$ make CC=gcc
- alternativly, if you are short on disk space or just want the
- simulator built:
+ alternativly, if you are short on disk space or just want the
+ simulator built:
$ ( cd libiberty && make CC=gcc )
$ ( cd bfd && make CC=gcc )
$ ( cd sim/ppc && make CC=gcc )
-5. Install
+ 5. Install
$ make CC=gcc install
- or just
+ or just
$ cp gdb/gdb ~/bin/powerpc-unknown-eabisim-gdb
$ cp sim/ppc/run ~/bin/powerpc-unknown-eabisim-run
-USING THE SIMULATOR:
+How do I use the simulator?
+
-(I assume that you've unpacked the psim-test archive).
+ (I assume that you've unpacked the psim-test archive).
-1. As a standalone program
+ 1. As a standalone program
- Print out the users environment:
+ Print out the users environment:
$ powerpc-unknown-eabisim-run envp
- Print out the arguments:
+ Print out the arguments:
$ powerpc-unknown-eabisim-run argv a b c
- Check that sbrk works:
+ Check that sbrk works:
$ powerpc-unknown-eabisim-run break
-2. Example of running GDB:
+ 2. Example of running GDB:
- The main thing to note is that before you can run the simulator
- you must enable it. The example below illustrates this:
+ The main thing to note is that before you can run the simulator
+ you must enable it. The example below illustrates this:
$ powerpc-unknown-eabisim-gdb envp
(gdb) target sim
.
-BUGS AND PROBLEMS:
+Where do I send bugs or report problems?
-There is a mailing list (subscribe through majordomo@ci.com.au) (that
-is almost never used) at:
+ There is a mailing list (subscribe through majordomo@ci.com.au) (that
+ is almost never used) at:
powerpc-psim@ci.com.au
-If I get the ftp archive updated I post a note to that mailing list.
-In addition your welcome to send bugs or problems either to me or to
-that e-mail list.
+ If I get the ftp archive updated I post a note to that mailing list.
+ In addition your welcome to send bugs or problems either to me or to
+ that e-mail list.
-KNOWN PROBLEMS:
+Are there any known problems?
-See the ChangeLog file looking for lines taged with the word FIXME.
+ See the ChangeLog file looking for lines taged with the word FIXME.
-COREFILE.C: The implementation of corefile.c (defined by corefile.h) isn't the
-best. It is intended to be functionaly correct rather than fast.
+ COREFILE.C: The implementation of corefile.c (defined by
+ corefile.h) isn't the best. It is intended to be functionaly
+ correct rather than fast. One option being considered
+ is to add a data cache to reduce the overhead of the most
+ common case of data read/writes.
-HTAB (page) code for OEA model untested. Some of the vm code
-instructions unimplemented.
+ HTAB (page) code for OEA model untested. Some of the vm code
+ instructions unimplemented.
-Lacks PowerOpen (a.k.a. XCOFF a.k.a. AIX) and NT startups. The
-PowerOpen worked until I added the ELF one.
+ Lacks PowerOpen (a.k.a. XCOFF a.k.a. AIX) and NT startups. The
+ PowerOpen worked until I added the ELF one.
-Missing VEA system calls.
+ Missing VEA system calls.
-Missing or commented out instructions.
+ Missing or commented out instructions.
-64bit target untested.
+ 64bit target untested.
-64bit host broken. For instance use of scanf "%x", &long long.
+ 64bit host broken. For instance use of scanf "%x", &long long.
-Event code for pending events from within signal handlers not
-finished/tested.
+ Event code for pending events from within signal handlers not
+ finished/tested.
-Better and more devices.
+ Better and more devices.
-PORTABILITY (Notes taken from Michael Meissner): Heavy use of the ##
-operator - fix using the clasic X/**/Y hack; Use of the signed
-keyword. In particular, signed char has no analogue in classic C
-(though most implementations of classic C use signed chars); Use of
-long long which restricts the target compiler to be GCC.
+ PORTABILITY (Notes taken from Michael Meissner): Heavy use of the ##
+ operator - fix using the clasic X/**/Y hack; Use of the signed
+ keyword. In particular, signed char has no analogue in classic C
+ (though most implementations of classic C use signed chars); Use of
+ long long which restricts the target compiler to be GCC.
-THANKS:
+Who helped?
-Thanks go to the following who each helped in some way.
+ Thanks go to the following who each helped in some way.
Allen Briggs, Bett Koch, David Edelsohn, Gordon Irlam,
Michael Meissner, Bob Mercier, Richard Perini,
Richard Stallman, Mitchele Walker
+
projects / deliverable / binutils-gdb.git / commitdiff
