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Add a simple DMA engine that sits behind a FIFO. This engine can be used by devices that need to read large amounts of data (e.g., display controllers). Most aspects of the controller, such as FIFO size, maximum number of in-flight accesses, and maximum request sizes can be configured. The DMA copies blocks of data into its FIFO. Transfers are initiated with a call to startFill() command that takes a start address and a size. Advanced users can create a derived class that overrides the onEndOfBlock() callback that is triggered when the last request to a block has been issued. At this point, the DMA engine is ready to start fetching a new block of data, potentially from a different address range. The DMA engine stops issuing new requests while it is draining. Care must be taken to ensure that devices that are fed by a DMA engine are suspended while the system is draining to avoid buffer underruns.
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.