1 2 3 PSIM 1.0.1 - Model of the PowerPC Environments 4 5 6 Copyright (C) 1994-1996, Andrew Cagney <cagney@highland.com.au>. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 2 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program; if not, write to the Free Software 20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 21 22 23 ---------------------------------------------------------------------- 24 25 26PSIM is a program written in extended ANSI-C that implements an 27instruction level simulation of the PowerPC environment. It is freely 28available in source code form under the terms of the GNU General 29Public License (version 2 or later). 30 31The PowerPC Architecture is described as having three levels of 32compliance: 33 34 UEA - User Environment Architecture 35 VEA - Virtual Environment Architecture 36 OEA - Operating Environment Architecture 37 38PSIM both implements all three levels of the PowerPC and includes (for 39each level) a corresponding simulated run-time environment. 40 41In addition, PSIM, to the execution unit level, models the performance 42of most of the current PowerPC implementations (contributed by Michael 43Meissner). This detailed performance monitoring (unlike many other 44simulators) resulting in only a relatively marginal reduction in the 45simulators performance. 46 47 48A description of how to build PSIM is contained in the file: 49 50 ftp://ftp.ci.com.au/pub/psim/INSTALL 51 or ftp://cambridge.cygnus.com/pub/psim/INSTALL 52 53while an overview of how to use PSIM is in: 54 55 ftp://ftp.ci.com.au/pub/psim/RUN 56or ftp://cambridge.cygnus.com/pub/psim/RUN 57 58This file is found in: 59 60 ftp://ftp.ci.com.au/pub/psim/README 61or ftp://cambridge.cygnus.com/pub/psim/README 62 63 64Thanks goes firstly to: 65 66 Corinthian Engineering Pty Ltd 67 Cygnus Support 68 Highland Logic Pty Ltd 69 70who provided the resources needed for making this software available 71on the Internet. 72 73More importantly I'd like to thank the following individuals who each 74contributed in their own unique way: 75 76 Allen Briggs, Bett Koch, David Edelsohn, Gordon Irlam, 77 Michael Meissner, Bob Mercier, Richard Perini, Dale Rahn, 78 Richard Stallman, Mitchele Walker 79 80 81 Andrew Cagney 82 Feb, 1995 83 84 85 ---------------------------------------------------------------------- 86 87 88 What features does PSIM include? 89 90 Monitoring and modeling 91 92 PSIM includes (thanks to Michael Meissner) 93 a detailed model of most of the PowerPC 94 implementations to the functional unit level. 95 96 97 SMP 98 99 The PowerPC ISA defines SMP synchronizing instructions. 100 This simulator implements a limited, but functional, 101 subset of the PowerPC synchronization instructions 102 behaviour. Programs that restrict their synchronization 103 primitives to those that work with this functional 104 sub-set (eg P() and V()) are able to run on the SMP 105 version of PSIM. 106 107 People intending to use this system should study 108 the code implementing the lwarx instruction. 109 110 ENDIAN SUPPORT 111 112 PSIM implements the PowerPC's big and little (xor 113 endian) modes and correctly simulates code that 114 switches between these two modes. 115 116 In addition, psim can model a true little-endian 117 machine. 118 119 ISA (Instruction Set Architecture) models 120 121 PSIM includes a model of the UEA, VEA and OEA. This 122 includes the time base registers (VEA) and HTAB 123 and BATS (OEA). 124 125 In addition, a preliminary model of the 64 bit 126 PowerPC architecture is implemented. 127 128 IO Hardware 129 130 PSIM's internals are based around the concept 131 of a Device Tree. This tree intentionally 132 resembles that of the Device Tree found in 133 OpenBoot firmware. PSIM is flexible enough 134 to allow the user to fully configure this device 135 tree (and consequently the hardware model) at 136 run time. 137 138 Run-time environments: 139 140 PSIM's UEA model includes emulation for BSD 141 based UNIX system calls. 142 143 PSIM's OEA model includes emulation of either: 144 145 o OpenBoot client interface 146 147 o MOTO's BUG interface. 148 149 150 Floating point 151 152 Preliminary support for floating point is included. 153 154 155 Who would be interested in PSIM? 156 157 o the curious 158 159 Using psim, gdb, gcc and binutils the curious 160 user can construct an environment that allows 161 them to play with PowerPC Environment without 162 the need for real hardware. 163 164 165 o the analyst 166 167 PSIM includes many (contributed) monitoring 168 features which (unlike many other simulators) 169 do not come with a great penalty in performance. 170 171 Thus the performance analyst is able to use 172 this simulator to analyse the performance of 173 the system under test. 174 175 If PSIM doesn't monitor a components of interest, 176 the source code is freely available, and hence 177 there is no hinderance to changing things 178 to meet a specific analysts needs. 179 180 181 o the serious SW developer 182 183 PSIM models all three levels of the PowerPC 184 Architecture: UEA, VEA and OEA. Further, 185 the internal design is such that PSIM can 186 be extended to support additional requirements. 187 188 189 What performance analysis measurements can PSIM perform? 190 191 Below is the output from a recent analysis run 192 (contributed by Michael Meissner): 193 194 For the following program: 195 196 long 197 simple_rand () 198 { 199 static unsigned long seed = 47114711; 200 unsigned long this = seed * 1103515245 + 12345; 201 seed = this; 202 /* cut-cut-cut - see the file RUN.psim */ 203 } 204 205 Here is the current output generated with the -I switch on a P90 206 (the compiler used is the development version of GCC with a new 207 scheduler replacing the old one): 208 209 CPU #1 executed 41,994 AND instructions. 210 CPU #1 executed 519,785 AND Immediate instructions. 211 . 212 . 213 . 214 CPU #1 executed 1 System Call instruction. 215 CPU #1 executed 207,746 XOR instructions. 216 217 CPU #1 executed 23,740,856 cycles. 218 CPU #1 executed 10,242,780 stalls waiting for data. 219 CPU #1 executed 1 stall waiting for a function unit. 220 . 221 . 222 . 223 CPU #1 executed 3,136,229 branch functional unit instructions. 224 CPU #1 executed 16,949,396 instructions that were accounted for in timing info. 225 CPU #1 executed 871,920 data reads. 226 CPU #1 executed 971,926 data writes. 227 CPU #1 executed 221 icache misses. 228 CPU #1 executed 16,949,396 instructions in total. 229 230 Simulator speed was 250,731 instructions/second 231 232 233 What motivated PSIM? 234 235 As an idea, psim was first discussed seriously during mid 236 1994. At that time its main objectives were: 237 238 239 o good performance 240 241 Many simulators loose out by only providing 242 a binary interface to the internals. This 243 interface eventually becomes a bottle neck 244 in the simulators performance. 245 246 It was intended that PSIM would avoid this 247 problem by giving the user access to the 248 full source code. 249 250 Further, by exploiting the power of modern 251 compilers it was hoped that PSIM would achieve 252 good performance with out having to compromise 253 its internal design. 254 255 256 o practical portability 257 258 Rather than try to be portable to every 259 C compiler on every platform, it was decided 260 that PSIM would restrict its self to supporting 261 ANSI compilers that included the extension 262 of a long long type. 263 264 GCC is one such compiler, consequently PSIM 265 should be portable to any machine running GCC. 266 267 268 o flexibility in its design 269 270 PSIM should allow the user to select the 271 features required and customise the build 272 accordingly. By having the source code, 273 the compiler is able to eliminate any un 274 used features of the simulator. 275 276 After all, let the compiler do the work. 277 278 279 o SMP 280 281 A model that allowed the simulation of 282 SMP platforms with out the large overhead 283 often encountered with such models. 284 285 286 PSIM achieves each of these objectives. 287 288 289 Is PSIM PowerPC Platform (PPCP) (nee CHRP) Compliant? 290 291 No. 292 293 Among other things it does not have an Apple ROM socket. 294 295 296 Could PSIM be extended so that it models a CHRP machine? 297 298 Yes. 299 300 PSIM has been designed with the CHRP spec in mind. To model 301 a CHRP desktop the following would need to be added: 302 303 o An apple ROM socket :-) 304 305 o Model of each of the desktop IO devices 306 307 o An OpenPIC device. 308 309 o RTAS (Run Time Abstraction Services). 310 311 o A fully populated device tree. 312 313 314 Is the source code available? 315 316 Yes. 317 318 The source code to PSIM is available under the terms of 319 the GNU Public Licence. This allows you to distribute 320 the source code for free but with certain conditions. 321 322 See the file: 323 324 ftp://archie.au/gnu/COPYING 325 326 For details of the terms and conditions. 327 328 329 Where do I send bugs or report problems? 330 331 There is a mailing list (subscribe through majordomo@ci.com.au) at: 332 333 powerpc-psim@ci.com.au 334 335 If I get the ftp archive updated I post a note to that mailing list. 336 In addition your welcome to send bugs or problems either to me or to 337 that e-mail list. 338 339 This list currently averages zero articles a day. 340 341 342 Does PSIM have any limitations or problems? 343 344 PSIM can't run rs6000/AIX binaries - At present PSIM can only 345 simulate static executables. Since an AIX executable is 346 never static, PSIM is unable to simulate its execution. 347 348 PSIM is still under development - consequently there are going 349 to be bugs. 350 351 See the file BUGS (included in the distribution) for any 352 other outstanding issues. 353 354