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(SIM_{OBJS,EXTRA_CFLAGS,EXTRA_CLEAN}): Define. * configure.in: Simplify using macros in ../common/aclocal.m4. * configure: Regenerated. * tconfig.in: New file. |
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.Sanitize | ||
ChangeLog | ||
configure | ||
configure.in | ||
gencode.c | ||
interp.c | ||
Makefile.in | ||
README.Cygnus | ||
support.h | ||
tconfig.in |
> README.Cygnus ------------------------------------------------------------------------------- The following are the main reasons for constructing the simulator as a generator: 1) Avoid large fixed decode source file, with lots of #ifs controlling the compilation. i.e. keep the source cleaner, smaller and easier to parse. 2) Allow optimum code to be created, without run-time checks on instruction types. Ensure that the simulator engine only includes code for the architecture being targetted. e.g. This avoids run-time checks on ISA conformance, aswell as increasing throughput. 3) Allow updates to the instruction sets to be added quickly. Having a table means that the information is together, and is easier to manipulate. Having the table generate the engine, rather than the run-time parse the table gives higher performance at simulation time. 4) Keep all the similar simulation code together. i.e. have a single place where, for example, the addition code is held. This ensures that updates to the simulation are not spread over a large flat source file maintained by the developer. ------------------------------------------------------------------------------- To keep the simulator simple (and to avoid the slight chance of mis-matched files) the manifests describing an engine, and the simulator engine itself, are held in the same source file. This means that the engine must be included twice, with the first pass controlled by the SIM_MANIFESTS definition. ------------------------------------------------------------------------------- > EOF README.Cygnus