Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-This directory contains the source code to the program PSIM that
-implements a model of a PowerPC platform. PSIM can either be built
-standalone or as part of the debugger GDB.
+This directory contains the source code to the program PSIM.
What is PSIM?
- PSIM is an ANSI C program that can be configured to model
- various PowerPC platforms.
+ PSIM is an ANSI C program that implements an instruction
+ level model of the PowerPC architecture.
- The platform that is modeled can vary from:
+ It can be configured to model various PowerPC platforms
+ and include:
o A user program environment (UEA) complete
with emulated system calls
interacting with each other and various
modeled hardware devices.
+ For each of these models PSIM is able perform a detailed
+ analysis of the machines performance.
-Is the source code available?
-
- Yes.
-
- The source code to PSIM is available under the terms of
- the GNU Public Licence. This allows you to distribute
- the source code for free but with certain conditions.
-
-
-What motivated PSIM?
-
- As an idea, psim was first discussed seriously during mid
- 1994. At that time its main objectives were:
-
-
- o good performance
-
- 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?
of new hardware devices so that they can be
included in a custom hardware model.
- Emulation
+ OS-Emulation
+
+ PSIM's UEA model includes emulation for UNIX system
+ calls.
+
+ PSIM's OEA model includes emulation of either:
+
+ o OpenBoot client interface
+
+ o MOTO's BUG interface.
- 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.
-Is PSIM CHRP Compliant?
+
+What performance analysis measurements can PSIM perform?
+
+ Below is the output from a recent analysis run
+ (contributed by Michael Meissner):
+
+ For the following program:
+
+ long
+ simple_rand ()
+ {
+ static unsigned long seed = 47114711;
+ unsigned long this = seed * 1103515245 + 12345;
+ seed = this;
+ return this >> 8;
+ }
+
+ unsigned long int
+ random_bitstring ()
+ {
+ unsigned long int x;
+ int ran, n_bits;
+ int tot_bits = 0;
+
+ x = 0;
+ for (;;)
+ {
+ ran = simple_rand ();
+ n_bits = (ran >> 1) % 16;
+ tot_bits += n_bits;
+
+ if (n_bits == 0)
+ return x;
+ else
+ {
+ x <<= n_bits;
+ if (ran & 1)
+ x |= (1 << n_bits) - 1;
+
+ if (tot_bits > 8 * sizeof (long) + 6)
+ return x;
+ }
+ }
+ }
+
+ #define ABS(x) ((x) >= 0 ? (x) : -(x))
+
+ main ()
+ {
+ int i;
+
+ for (i = 0; i < 50000; i++)
+ {
+ unsigned long x, y;
+ x = random_bitstring ();
+ y = random_bitstring ();
+
+ if (sizeof (int) == sizeof (long))
+ goto save_time;
+
+ { unsigned long xx = x, yy = y, r1, r2;
+ if (yy == 0) continue;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (r2 >= yy || r1 * yy + r2 != xx)
+ abort ();
+ }
+ { signed long xx = x, yy = y, r1, r2;
+ if ((unsigned long) xx << 1 == 0 && yy == -1)
+ continue;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (ABS (r2) >= (unsigned long) ABS (yy) || (signed long) (r1 * yy + r2) != xx)
+ abort ();
+ }
+ save_time:
+ { unsigned int xx = x, yy = y, r1, r2;
+ if (yy == 0) continue;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (r2 >= yy || r1 * yy + r2 != xx)
+ abort ();
+ }
+ { signed int xx = x, yy = y, r1, r2;
+ if ((unsigned int) xx << 1 == 0 && yy == -1)
+ continue;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (ABS (r2) >= (unsigned int) ABS (yy) || (signed int) (r1 * yy + r2) != xx)
+ abort ();
+ }
+ { unsigned short xx = x, yy = y, r1, r2;
+ if (yy == 0) continue;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (r2 >= yy || r1 * yy + r2 != xx)
+ abort ();
+ }
+ { signed short xx = x, yy = y, r1, r2;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (ABS (r2) >= (unsigned short) ABS (yy) || (signed short) (r1 * yy + r2) != xx)
+ abort ();
+ }
+ { unsigned char xx = x, yy = y, r1, r2;
+ if (yy == 0) continue;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (r2 >= yy || r1 * yy + r2 != xx)
+ abort ();
+ }
+ { signed char xx = x, yy = y, r1, r2;
+ r1 = xx / yy;
+ r2 = xx % yy;
+ if (ABS (r2) >= (unsigned char) ABS (yy) || (signed char) (r1 * yy + r2) != xx)
+ abort ();
+ }
+ }
+
+ exit (0);
+ }
+
+ Here is the current output generated with the -I switch on a 90 Mhz
+ pentium (the compiler used is the devlopment version of GCC with a new
+ scheduler replacing the old one):
+
+ CPU #1 executed 41,994 AND instructions.
+ CPU #1 executed 519,785 AND Immediate instructions.
+ CPU #1 executed 680,058 Add instructions.
+ CPU #1 executed 41,994 Add Extended instructions.
+ CPU #1 executed 921,916 Add Immediate instructions.
+ CPU #1 executed 221,199 Add Immediate Carrying instructions.
+ CPU #1 executed 943,823 Add Immediate Shifted instructions.
+ CPU #1 executed 471,909 Add to Zero Extended instructions.
+ CPU #1 executed 571,915 Branch instructions.
+ CPU #1 executed 1,992,403 Branch Conditional instructions.
+ CPU #1 executed 571,910 Branch Conditional to Link Register instructions.
+ CPU #1 executed 320,431 Compare instructions.
+ CPU #1 executed 471,911 Compare Immediate instructions.
+ CPU #1 executed 145,867 Compare Logical instructions.
+ CPU #1 executed 442,414 Compare Logical Immediate instructions.
+ CPU #1 executed 1 Condition Register XOR instruction.
+ CPU #1 executed 103,873 Divide Word instructions.
+ CPU #1 executed 104,275 Divide Word Unsigned instructions.
+ CPU #1 executed 132,510 Extend Sign Byte instructions.
+ CPU #1 executed 178,895 Extend Sign Half Word instructions.
+ CPU #1 executed 871,920 Load Word and Zero instructions.
+ CPU #1 executed 41,994 Move From Condition Register instructions.
+ CPU #1 executed 100,005 Move from Special Purpose Register instructions.
+ CPU #1 executed 100,002 Move to Special Purpose Register instructions.
+ CPU #1 executed 804,619 Multiply Low Word instructions.
+ CPU #1 executed 421,201 OR instructions.
+ CPU #1 executed 471,910 OR Immediate instructions.
+ CPU #1 executed 1,292,020 Rotate Left Word Immediate then AND with Mask instructions.
+ CPU #1 executed 663,613 Shift Left Word instructions.
+ CPU #1 executed 1,151,564 Shift Right Algebraic Word Immediate instructions.
+ CPU #1 executed 871,922 Store Word instructions.
+ CPU #1 executed 100,004 Store Word with Update instructions.
+ CPU #1 executed 887,804 Subtract From instructions.
+ CPU #1 executed 83,988 Subtract From Immediate Carrying instructions.
+ CPU #1 executed 1 System Call instruction.
+ CPU #1 executed 207,746 XOR instructions.
+
+ CPU #1 executed 23,740,856 cycles.
+ CPU #1 executed 10,242,780 stalls waiting for data.
+ CPU #1 executed 1 stall waiting for a function unit.
+ CPU #1 executed 1 stall waiting for serialization.
+ CPU #1 executed 1,757,900 times a writeback slot was unavilable.
+ CPU #1 executed 1,088,135 branches.
+ CPU #1 executed 2,048,093 conditional branches fell through.
+ CPU #1 executed 1,088,135 successful branch predictions.
+ CPU #1 executed 904,268 unsuccessful branch predictions.
+ CPU #1 executed 742,557 branch if the condition is FALSE conditional branches.
+ CPU #1 executed 1,249,846 branch if the condition is TRUE conditional branches.
+ CPU #1 executed 571,910 branch always conditional branches.
+ CPU #1 executed 9,493,653 1st single cycle integer functional unit instructions.
+ CPU #1 executed 1,220,900 2nd single cycle integer functional unit instructions.
+ CPU #1 executed 1,254,768 multiple cycle integer functional unit instructions.
+ CPU #1 executed 1,843,846 load/store functional unit instructions.
+ CPU #1 executed 3,136,229 branch functional unit instructions.
+ CPU #1 executed 16,949,396 instructions that were accounted for in timing info.
+ CPU #1 executed 871,920 data reads.
+ CPU #1 executed 971,926 data writes.
+ CPU #1 executed 221 icache misses.
+ CPU #1 executed 16,949,396 instructions in total.
+
+ Simulator speed was 250,731 instructions/second
+
+
+
+What motivated PSIM?
+
+ As an idea, psim was first discussed seriously during mid
+ 1994. At that time its main objectives were:
+
+
+ o good performance
+
+ Many simulators loose out by only providing
+ a binary interface to the internals. This
+ interface eventually becomes 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.
+
+
+Is PSIM PowerPC Platform (PPCP) (nee CHRP) Compliant?
No.
- However, PSIM does include all the hooks that are needed to
- construct a model of a CHRP compliant platform.
+ Among other things it does not have an Apple ROM socket.
+
+
+Can PSIM be configured so that it models a CHRP machine?
+
+ Yes.
+
+ PSIM has been designed with the CHRP spec in mind. To model
+ a CHRP desktop a user would need to add the following:
+
+ o An apple rom socket :-)
+
+ o Model of each of the desktop IO devices
+ (some may already be implemented).
+
+ o An OpenPIC (Open Programmable Interrupt
+ Controller) device. (it may by now be
+ implemented).
- That is:
+ o RTAS (Run Time Abstraction Services).
- o OpenBoot client software
+ o A fully populated device tree.
- o OpenPIC interrupt controller
- o Hooks to implement a RTAS interface
+Is the source code available?
+
+ Yes.
- o the ability to add a model of each of the
- hardware devices required by a CHRP compliant
- desktop.
+ The source code to PSIM is available under the terms of
+ the GNU Public Licence. This allows you to distribute
+ the source code for free but with certain conditions.
How do I build PSIM?
gdb-4.15.tar.gz From your favorite GNU ftp site.
- I've also tested psim-951016 with
+ I've also tested psim with
gdb-4.15.1. If you would prefer
a graphical development environment
then PSIM can also be built with
This file.
- ftp://ftp.ci.com.au/pub/clayton/gdb-4.15+psim-951016.diff.gz
+ ftp://ftp.ci.com.au/pub/clayton/gdb-4.15+psim.diff.gz
+
+ Firstly this file contains a few
+ minor changes to gdb-4.15 so that it
+ will build PSIM as part of GDB.
- This contains a few minor patches to
- gdb-4.15 so that will include psim
- when it is built.
+ ftp://ftp.ci.com.au/pub/clayton/gdb-4.15+note.diff.gz
- ftp://ftp.ci.com.au/pub/clayton/psim-test-951016.tar.gz
+ Add suport for note sections (used
+ by OpenBoot PowerPC programs).
- (Optional) A scattering of pre-compiled
- programs that run under the simulator.
+
+ ftp://ftp.ci.com.au/pub/clayton/gdb-4.15+attach.diff.gz
+
+ Allow the gdb attach command to
+ work with simulators.
- ftp://ftp.ci.com.au/pub/clayton/gdb-4.15+psim-951016.tar.gz
+ ftp://ftp.ci.com.au/pub/clayton/psim-960119.tar.gz
This contains the psim files proper.
installing gnu's patch.
- In addition, I'm slowly building up a set of useful patches
- to gdb-4.15 that are useful. You will want to also apply
- these patches:
-
-
- ftp://ftp.ci.com.au/pub/clayton/gdb-4.15+attach.diff.gz
-
- Patch to gdb that allows the `attach'
- command to be used when connecting to a
- simulator.
-
- See that file for more information.
-
- ftp://ftp.ci.com.au/pub/clayton/gdb-4.15+note.diff.gz
-
- Patch to gdb's bfd that adds basic support
- for a .note section. OpenBoot makes
- use of a .note section when loading a
- boot image.
-
-
Procedure:
0. A starting point
$ ls -1
- gdb-4.15+psim-951016.diff.gz
- gdb-4.15+psim-951016.tar.gz
+ gdb-4.15+attach.diff.gz
+ gdb-4.15+note.diff.gz
+ gdb-4.15+psim.diff.gz
+ gdb-4.15+psim.diff.gz
gdb-4.15.tar.gz
- psim-test-951016.tar.gz
+ psim-960119.tar.gz
1. Unpack gdb
$ cd gdb-4.15
- $ gunzip < ../gdb-4.15+psim-951016.diff.gz | more
- $ gunzip < ../gdb-4.15+psim-951016.diff.gz | patch -p1
+ $ gunzip < ../gdb-4.15+psim.diff.gz | more
+ $ gunzip < ../gdb-4.15+psim.diff.gz | patch -p1
- $ gunzip < ../gdb-4.15+psim-951016.tar.gz | tar tvf -
- $ gunzip < ../gdb-4.15+psim-951016.tar.gz | tar xvf -
+ $ gunzip < ../gdb-4.15+psim-960119.tar.gz | tar tvf -
+ $ gunzip < ../gdb-4.15+psim-960119.tar.gz | tar xvf -
You may also want to consider applying the `attach' and
`note' patches that are available vis:
eabisim is needed as by default (because PSIM needs GCC) the
simulator is not built.
+ [If building with a more recent gdb snapshot then the
+ command:
+
+ $CC=gcc ./configure --enable-sim-powerpc
+
+ is used.]
4. Build
(that include new features) are made available. Several of
the more recent snapshots are:
- ftp://ftp.ci.com.au/pub/clayton/psim-951219.tar.gz
-
- Hopefully merges in Michael stuff
- with mine, adds multiple emulations
- (OpenBoot and NetBSD), revamps
- inline stuff, rearanges devices so
- that phandls and ihandles can be
- implemented.
-
- ftp://ftp.ci.com.au/pub/clayton/psim-951203.tar.gz
-
- A good snapshot
-
- This includes extensions from Michael
- Meissner that add monitoring of the
- PowerPC's register and bus architectures.
-
+ <to-be-advised>
To build/install one of these snapshots, you replace the
current gdb/sim/ppc directory with the one in the update,
that fixes do not introduce new bugs. This test suite
like psim is updated:
- ftp://ftp.ci.com.au/pub/clayton/psim-test-951218.tar.gz
+ ftp://ftp.ci.com.au/pub/clayton/psim-test-960118.tar.gz
Prebuilt test programs for PSIM.
Includes examples of UEA, VEA and
Requires gcc-2.7.2 and binutils-2.6
to rebuild.
- ftp://ftp.ci.com.au/pub/clayton/psim-test-951016.tar.gz
-
- (Optional) A scattering of pre-compiled
- programs that run under the simulator.
-
How do I use the simulator?
Who helped?
- Thanks go to the following who each helped in some way.
+ Thanks go to the following who each helped in their own
+ way:
Allen Briggs, Bett Koch, David Edelsohn, Gordon Irlam,
- Michael Meissner, Bob Mercier, Richard Perini,
+ Michael Meissner, Bob Mercier, Richard Perini, Dale Rahn
Richard Stallman, Mitchele Walker
-
projects / deliverable / binutils-gdb.git / commitdiff
