1 2 3 PSIM 1.0.1 - Model of the PowerPC Environments 4 5 6 Copyright (C) 1994-1996, Andrew Cagney <cagney (a] 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 3 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, see <http://www.gnu.org/licenses/>. 20 21 22 ---------------------------------------------------------------------- 23 24 25 PSIM is a program written in extended ANSI-C that implements an 26 instruction level simulation of the PowerPC environment. It is freely 27 available in source code form under the terms of the GNU General 28 Public License (version 3 or later). 29 30 The PowerPC Architecture is described as having three levels of 31 compliance: 32 33 UEA - User Environment Architecture 34 VEA - Virtual Environment Architecture 35 OEA - Operating Environment Architecture 36 37 PSIM both implements all three levels of the PowerPC and includes (for 38 each level) a corresponding simulated run-time environment. 39 40 In addition, PSIM, to the execution unit level, models the performance 41 of most of the current PowerPC implementations (contributed by Michael 42 Meissner). This detailed performance monitoring (unlike many other 43 simulators) resulting in only a relatively marginal reduction in the 44 simulators performance. 45 46 47 A description of how to build PSIM is contained in the file: 48 49 ftp://ftp.ci.com.au/pub/psim/INSTALL 50 or ftp://cambridge.cygnus.com/pub/psim/INSTALL 51 52 while an overview of how to use PSIM is in: 53 54 ftp://ftp.ci.com.au/pub/psim/RUN 55 or ftp://cambridge.cygnus.com/pub/psim/RUN 56 57 This file is found in: 58 59 ftp://ftp.ci.com.au/pub/psim/README 60 or ftp://cambridge.cygnus.com/pub/psim/README 61 62 63 Thanks goes firstly to: 64 65 Corinthian Engineering Pty Ltd 66 Cygnus Support 67 Highland Logic Pty Ltd 68 69 who provided the resources needed for making this software available 70 on the Internet. 71 72 More importantly I'd like to thank the following individuals who each 73 contributed in their own unique way: 74 75 Allen Briggs, Bett Koch, David Edelsohn, Gordon Irlam, 76 Michael Meissner, Bob Mercier, Richard Perini, Dale Rahn, 77 Richard Stallman, Mitchele Walker 78 79 80 Andrew Cagney 81 Feb, 1995 82 83 84 ---------------------------------------------------------------------- 85 86 87 What features does PSIM include? 88 89 Monitoring and modeling 90 91 PSIM includes (thanks to Michael Meissner) 92 a detailed model of most of the PowerPC 93 implementations to the functional unit level. 94 95 96 SMP 97 98 The PowerPC ISA defines SMP synchronizing instructions. 99 This simulator implements a limited, but functional, 100 subset of the PowerPC synchronization instructions 101 behaviour. Programs that restrict their synchronization 102 primitives to those that work with this functional 103 sub-set (eg P() and V()) are able to run on the SMP 104 version of PSIM. 105 106 People intending to use this system should study 107 the code implementing the lwarx instruction. 108 109 ENDIAN SUPPORT 110 111 PSIM implements the PowerPC's big and little (xor 112 endian) modes and correctly simulates code that 113 switches between these two modes. 114 115 In addition, psim can model a true little-endian 116 machine. 117 118 ISA (Instruction Set Architecture) models 119 120 PSIM includes a model of the UEA, VEA and OEA. This 121 includes the time base registers (VEA) and HTAB 122 and BATS (OEA). 123 124 In addition, a preliminary model of the 64 bit 125 PowerPC architecture is implemented. 126 127 IO Hardware 128 129 PSIM's internals are based around the concept 130 of a Device Tree. This tree intentionally 131 resembles that of the Device Tree found in 132 OpenBoot firmware. PSIM is flexible enough 133 to allow the user to fully configure this device 134 tree (and consequently the hardware model) at 135 run time. 136 137 Run-time environments: 138 139 PSIM's UEA model includes emulation for BSD 140 based UNIX system calls. 141 142 PSIM's OEA model includes emulation of either: 143 144 o OpenBoot client interface 145 146 o MOTO's BUG interface. 147 148 149 Floating point 150 151 Preliminary support for floating point is included. 152 153 154 Who would be interested in PSIM? 155 156 o the curious 157 158 Using psim, gdb, gcc and binutils the curious 159 user can construct an environment that allows 160 them to play with PowerPC Environment without 161 the need for real hardware. 162 163 164 o the analyst 165 166 PSIM includes many (contributed) monitoring 167 features which (unlike many other simulators) 168 do not come with a great penalty in performance. 169 170 Thus the performance analyst is able to use 171 this simulator to analyse the performance of 172 the system under test. 173 174 If PSIM doesn't monitor a components of interest, 175 the source code is freely available, and hence 176 there is no hindrance to changing things 177 to meet a specific analysts needs. 178 179 180 o the serious SW developer 181 182 PSIM models all three levels of the PowerPC 183 Architecture: UEA, VEA and OEA. Further, 184 the internal design is such that PSIM can 185 be extended to support additional requirements. 186 187 188 What performance analysis measurements can PSIM perform? 189 190 Below is the output from a recent analysis run 191 (contributed by Michael Meissner): 192 193 For the following program: 194 195 long 196 simple_rand () 197 { 198 static unsigned long seed = 47114711; 199 unsigned long this = seed * 1103515245 + 12345; 200 seed = this; 201 /* cut-cut-cut - see the file RUN.psim */ 202 } 203 204 Here is the current output generated with the -I switch on a P90 205 (the compiler used is the development version of GCC with a new 206 scheduler replacing the old one): 207 208 CPU #1 executed 41,994 AND instructions. 209 CPU #1 executed 519,785 AND Immediate instructions. 210 . 211 . 212 . 213 CPU #1 executed 1 System Call instruction. 214 CPU #1 executed 207,746 XOR instructions. 215 216 CPU #1 executed 23,740,856 cycles. 217 CPU #1 executed 10,242,780 stalls waiting for data. 218 CPU #1 executed 1 stall waiting for a function unit. 219 . 220 . 221 . 222 CPU #1 executed 3,136,229 branch functional unit instructions. 223 CPU #1 executed 16,949,396 instructions that were accounted for in timing info. 224 CPU #1 executed 871,920 data reads. 225 CPU #1 executed 971,926 data writes. 226 CPU #1 executed 221 icache misses. 227 CPU #1 executed 16,949,396 instructions in total. 228 229 Simulator speed was 250,731 instructions/second 230 231 232 What motivated PSIM? 233 234 As an idea, psim was first discussed seriously during mid 235 1994. At that time its main objectives were: 236 237 238 o good performance 239 240 Many simulators loose out by only providing 241 a binary interface to the internals. This 242 interface eventually becomes a bottle neck 243 in the simulators performance. 244 245 It was intended that PSIM would avoid this 246 problem by giving the user access to the 247 full source code. 248 249 Further, by exploiting the power of modern 250 compilers it was hoped that PSIM would achieve 251 good performance with out having to compromise 252 its internal design. 253 254 255 o practical portability 256 257 Rather than try to be portable to every 258 C compiler on every platform, it was decided 259 that PSIM would restrict its self to supporting 260 ANSI compilers that included the extension 261 of a long long type. 262 263 GCC is one such compiler, consequently PSIM 264 should be portable to any machine running GCC. 265 266 267 o flexibility in its design 268 269 PSIM should allow the user to select the 270 features required and customise the build 271 accordingly. By having the source code, 272 the compiler is able to eliminate any un 273 used features of the simulator. 274 275 After all, let the compiler do the work. 276 277 278 o SMP 279 280 A model that allowed the simulation of 281 SMP platforms with out the large overhead 282 often encountered with such models. 283 284 285 PSIM achieves each of these objectives. 286 287 288 Is PSIM PowerPC Platform (PPCP) (nee CHRP) Compliant? 289 290 No. 291 292 Among other things it does not have an Apple ROM socket. 293 294 295 Could PSIM be extended so that it models a CHRP machine? 296 297 Yes. 298 299 PSIM has been designed with the CHRP spec in mind. To model 300 a CHRP desktop the following would need to be added: 301 302 o An apple ROM socket :-) 303 304 o Model of each of the desktop IO devices 305 306 o An OpenPIC device. 307 308 o RTAS (Run Time Abstraction Services). 309 310 o A fully populated device tree. 311 312 313 Is the source code available? 314 315 Yes. 316 317 The source code to PSIM is available under the terms of 318 the GNU Public Licence. This allows you to distribute 319 the source code for free but with certain conditions. 320 321 See the file: 322 323 ftp://archie.au/gnu/COPYING 324 325 For details of the terms and conditions. 326 327 328 Where do I send bugs or report problems? 329 330 There is a mailing list (subscribe through majordomo (a] ci.com.au) at: 331 332 powerpc-psim (a] ci.com.au 333 334 If I get the ftp archive updated I post a note to that mailing list. 335 In addition your welcome to send bugs or problems either to me or to 336 that e-mail list. 337 338 This list currently averages zero articles a day. 339 340 341 Does PSIM have any limitations or problems? 342 343 PSIM can't run rs6000/AIX binaries - At present PSIM can only 344 simulate static executables. Since an AIX executable is 345 never static, PSIM is unable to simulate its execution. 346 347 PSIM is still under development - consequently there are going 348 to be bugs. 349 350 See the file BUGS (included in the distribution) for any 351 other outstanding issues. 352 353
Indexes created Sun Apr 26 00:22:38 UTC 2026