Changes between Initial Version and Version 1 of Soclib Cc/And Modelsim

Timestamp:

Mar 25, 2010, 12:15:14 PM (14 years ago)

Author:

Nicolas Pouillon

Comment:

--

Soclib Cc/And Modelsim

@@ +1 @@
+= Cosimulation using SoCLib components and RTL models =
+
+You may use CABA models together with RTL models using !ModelSim. This
+needs the following parts:
+ * a set of SystemC models
+ * a set of Verilog/VHDL models
+ * glue wrappers where needed, exporting a RTL model to SystemC or SystemC to RTL (not covered in this guide)
+ * a SystemC clock driver (we had some issues with vhdl clock driver), i.e. a module bagotting clock signal
+
+SystemC modules are SoCLib ones and are usually compiled with
+SoCLib-cc. They come with pure-c++ dependancies which must be linked
+together with the modules.
+
+Due to its simulator core design, !ModelSim has to compile SystemC
+modules a special way, and has a dedicated tool to compile SystemC/C++
+files: `sccom`.
+
+Soclib-cc has three main jobs:
+ * Select modules and dependancies from a platform description file,
+ * Explicitly instantiate C++ templates,
+ * Call the C++ compiler. Only this step is implemented in `sccom`.
+
+The flow is as in the picture:
+
+[[Image(flow.png,nolink)]]
+
+soclib-cc handles most of this automagically if correctly
+configured. This guide explains how to set things up.
+
+Moreover, the C/C++ only dependancies are not
+directly compileable with the dedicated !ModelSim tool, but can be
+''injected'' at the last time, for the linkage phase (`sccom -link`).
+
+= How to configure SoCLib-cc to call !ModelSim compiler driver =
+
+Sometimes, the C++-only dependencies of SystemC modules need to Know
+about SystemC types. Therefore, SystemC includes must be
+available.
+
+soclib-cc needs new configuration sections for
+ * the compiler used by sccom
+ * the path to !ModelSim's SystemC implementation
+ * used flags
+ * object file names pattern in sccom work directory
+
+For all these, we must create 3 new configurations in soclib-cc's
+configuration file:
+* a compiler
+* a SystemC library
+* a build environment
+
+{{{
+# Definition of the compiler used for ModelSim-usable SoCLib components.
+# We use sccom for components compilation and linkage, gcc/g++ for utilities
+config.toolchain_sccom = Config(
+        base = config.toolchain,
+        # Must use this.
+        tool_map = {
+          'SCCOM_CC':'sccom',
+          'SCCOM_CXX':'sccom',
+          'CC':'gcc',
+          'CXX':'g++',
+          'CC_LINKER':'sccom',
+          'CXX_LINKER':'sccom',
+        },
+        # Modelsim cant do parallel builds :'(
+        max_processes = 1,
+        # No cflags are needed, sccom forces them
+        cflags = [],
+        # Special features, it has a -link invocation needed at end...
+        libs = ['-link'],
+)
+        
+# Definition of the ModelSim SystemC implementation. Must modify the
+# path according to the ModelSim current installation.
+config.systemc_sccom = Config(
+        base = config.systemc,
+        # This special vendor attributes enables some quirks in soclib-cc
+        vendor = 'sccom',
+        # This is the path of the produced .o files when compiled with sccom.
+        # You have to try it by hand, and adapt
+        sc_workpath = "work/_sc/linux_gcc-4.1.2",
+        # Mandatory quirks
+        dir = "",
+        os = "",
+        libs = [],
+        # cflags have to be deducted from actual invocation
+        # Try using sccom -v by hand
+        cflags = ['-I/users/soft/mentor/modelsim-6.5c/modeltech/include/systemc',
+                  '-I/users/soft/mentor/modelsim-6.5c/modeltech/include'],
+        )
+
+# Definition of a new build environment, which can be referenced with 'soclib-cc -t'
+config.sccom = Config(
+        base = config.build_env,
+        toolchain = config.toolchain_sccom,
+        systemc = config.systemc_sccom,
+        # Where temporary files lies, beware that if you set a global path,
+        # you'll need a mechanism to make user-unique directories.
+        repos = "/tmp/",
+        )
+}}}
+
+= SystemC modules in !ModelSim limitations =
+
+All modules that may be used from the outside of the SystemC-part
+(from RTL or from GUI) have to be declared with a special macro
+(`SC_MODULE_EXPORT`).
+
+There is no `sc_main()` function in modelsim-based simulators. The top
+module must be a `sc_module` with no interfaces. This probably needs a
+rewrite of your netlists.
+
+If you use DSX-generated netlists, this is done transparently.
+
+= Usage =
+
+Now we configured soclib-cc, we can compile a complete SystemC system.
+
+Example to come