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The previous implementation used the value changed event to track when signals changed value, but there were a couple problems with this approach. First, this piggybacked on the sensitivity mechanism in some ways, but diverged in others. The sensitivity didn't notify a process when it was satisfied like other sensitivity types would, and it also ignored whether the process was disabled. Second, the value_changed_event is notified by a signal instance as a delta notification, but reset signals are supposed to act immediately. That means they should happen before all delta notifications, or in other words all delta notifications should see the reset status of a given process. That's particularly important in the case of wait(int n) where setting the reset clears the reset count, and the count is checked when determining whether or not to wake up a process when its sensitivity is satisfied, potentially by a delta notification. Third, by removing the middle man and not trying to repurpose the sensitivity mechanism, the code gets simpler and easier to understand. Change-Id: I0d05d11437291d368b060f6a45a207813615f113 Reviewed-on: https://gem5-review.googlesource.com/c/13294 Reviewed-by: Gabe Black <gabeblack@google.com> Maintainer: Gabe Black <gabeblack@google.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/Introduction, and for more information about building the simulator and getting started please see http://www.gem5.org/Documentation and http://www.gem5.org/Tutorials. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/Dependencies for more details concerning the minimum versions of the aforementioned tools. Once you have all dependencies resolved, type 'scons build/<ARCH>/gem5.opt' where ARCH is one of ALPHA, ARM, NULL, MIPS, POWER, SPARC, or X86. This will build an optimized version of the gem5 binary (gem5.opt) for the the specified architecture. See http://www.gem5.org/Build_System for more details and options. With the simulator built, have a look at http://www.gem5.org/Running_gem5 for more information on how to use gem5. The basic source release includes these subdirectories: - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you will need compiled system firmware (console and PALcode for Alpha), kernel binaries and one or more disk images. Please see the gem5 download page for these items at http://www.gem5.org/Download If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.