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diff --git a/sim/ppc/README.psim b/sim/ppc/README.psim new file mode 100644 index 0000000..c76c023 --- /dev/null +++ b/sim/ppc/README.psim @@ -0,0 +1,253 @@ + + PSIM + +Copyright (C) 1994-1995, Andrew Cagney <cagney@highland.com.au> + +This directory contains the program PSIM that models the PowerPC +architecture. It can either be run stand alone (psim) or linked with +GDB. + + +CONTENTS: + + psim-*.tar: + + psim-sim-*.tar.gz simulator source code + + psim-test-*.tar.gz test directory for simulator + + psim-gdb-*.diff.gz patches to integrated psim + into gdb + + gnu-*.tar: + + gnu-gdb-*.diff.gz patches to gdb that may have + already been merged into the + GDB source tree. + + gnu-*-*.diff.gz Other noise + + +BUILDING: + + o Install flex, bison, gnu-make, native gcc and probably also byacc. + + + o First you will need a fairly current copy of GDB (try the ftp site + ftp.cygnus.com:pub). I've built it with a beta version of gdb-4.15. + + Unpack gdb vis: + + $ gunzip < gdb-4.15.tar.gz | tar xf - + + + o Apply any patches that haven't yet been merged into the GDB source + tree. + + $ cd gdb-4.15 + $ gunzip < ../psim-gdb-*.diff.gz | patch -p1 + $ gunzip < ../gnu-gdb-*.diff.gz | patch -p1 + + + o Unpack the psim source code (and optionally the test directory) + + $ cd gdb-4.15 + $ gunzip < ../psim-sim-*.tar.gz | tar xvf - + $ gunzip < ../psim-test-*.tar.gz | tar xvf - + + + o Configure gdb as per normal. I use something along the lines of: + + $ cd gdb-4.15 + $ CC=gcc ./configure --target=powerpcle-unknown-eabi + + + o Build your entire gdb tree as per normal. Something along the + lines of: + + $ cd gdb-4.15 + $ make CC=gcc + . + . + . + + + + o Install it it all as per normal. Something along the lines of: + + $ cd gdb-4.15 + $ make CC=gcc install + + The program sim/ppc/psim is not installed. + + +RUNNING: + + PSIM can either be run as a stand alone program or as part + of gdb. The psim-test archive contains pre-compiled and + linked programs that can be run on PSIM. The notes below + assume that you have unpacked that tar archive. + + To rebuild the archive you will need to obtain a working + version of an ELF compiler/linker for the PowerPC. + + Example of running PSIM: + + Print out the users environment: + + $ sim/ppc/psim sim/ppc/test/envp + + Print out the arguments: + + $ sim/ppc/psim sim/ppc/test/argv a b c + + Check the OEA model: + + $ sim/ppc/psim sim/ppc/test/interrupt + + Check that sbrk works + + $ sim/ppc/psim sim/ppc/test/break + + Try for speed. The program count contains a loop + of two instructions which is looped <arg> times. + See later for how to make PSIM run 10-100 times + faster. + + $ time sim/ppc/sim sim/ppc/test/count 5000000 + $ expr 10 \* 1000 \* 1000 / <seconds> + + + Example of running GDB: + + The most important thing to be aware of is the fact + that before the simulator is used, the user must attach + to it (target sim) and than load the executable (load count). + + $ cd sim/ppc/test + $ powerpc-unknown-eabi-gdb count + (gdb) target sim + (gdb) load count + (gdb) break main + (gdb) run + . + . + . + + +CONFIGURATION: Making it go faster + + See the file sim/ppc/config.h (a.k.a. sim/ppc/data/ppc-config) + for notes. + + +KNOWN FEATURES + + SMP, dual-endian, VEA and OEA models, hardware devices + (console, icu, reset) ... + + +KNOWN PROBLEMS: + + Configuration could be better. + + HTAB (page) code for OEA model untested. Some of the vm code + instructions unimplemented. + + Doesn't detect/handle changing endian bits. In fact they are + ignored. + + Return from interrupt instruction unimplemented. + + Flush instruction cache instructions do nothing. Perhaphs they + should (if there is an instruction cache) flush it. + + PowerOpen VEA model (a.k.a XCOFF a.k.a AIX) broken. It was + working but that is before I changed the create stack frame + code into an ELF version. + + OpenBoot and PR*P interfaces missing. Open boot could be + implemented by putting special instructions at the address + of the OpenBoot callback functions. Those instructions + could than emulate OpenBoot behavour. + + VEA memory read/write performance could be improved by merging + the data sections. + + When reading in a VEA executable, the binaries text and data + sections are not made page aligned. + + Missing or commented out instructions. + + Lack of floating point support. + [workaround: build everything using -msoft-float] + + 64bit untested. + + Event code for pending events from signal handlers not + finished/tested. + + Better and more devices. + + Only two device trees VEA and OEA (clayton) and those hard coded. + Should be possible to specify a file containing a device tree + description as the program to run. At present it a device tree + file is detected causing psim to abort. + + I wonder if I've got my ppc.instructions copyright + notice correct. + + +THANKS: + + Thanks go to the following who each helped in some way. + + Allen Briggs, Bett Koch, David Edelsohn, + Michael Meissner, Bob Mercier, Richard Perini, + Richard Stallman, Mitchele Walker + + +---------------------------------------------------------------- + + +Random notes on performance: + + +$ cd test +time ../psim count `expr 10000000 / 2` +time ../psim volatile-count `expr 10000000 / 7` + +Where 2 and 7 are the number of instructions in the main loop. + + + 611/729 - baseline + +Tests: + + CFLAGS= -c -O2 -m486 -fomit-frame-pointer + + o different first/second level table/switch combinations + + 0 - use a table + 1 - use a simple switch + 2 - use an expanded switch + +i486DX4/100 - AMD + + 1/108/140 - switch=0/0/0,expand=2,inline=2,nia=1,cache=1 + 1/114/140 - switch=0/0/0,expand=2,inline=2,nia=1,cache=1 + 1/137/149 - switch=0/0,expand=2,inline=1,nia=1,cache=1 + 1/144/155 - switch=2/1,expand=2,inline=1,nia=1,cache=1 + 1/153/159 - switch=2/1,expand=0,inline=1,nia=1,cache=1 + 1/185/189 - switch=0/0,expand=0,inline=1,nia=1 + +i486DX2/66 + + 1/572/695 - switch=1/1,expand=0,inline=0 + 1/579/729 - switch=0/0,expand=0,inline=0 + 1/570/682 - switch=2/2,expand=0,inline=0 + 1/431/492 - switch=0/0,expand=0,inline=1,nia=0 + 1/271/292 - switch=2/1,expand=0,inline=1,nia=0 + 1/270/316 - switch=2/2,expand=0,inline=1,nia=0 + 1/271/281 - switch=1/1,expand=0,inline=1,nia=1 + 1/267/274 - switch=2/1,expand=0,inline=1,nia=1 |