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A few new attributes are defined for use in cell libraries: - iopad_external_pin: marks PAD cell's external-facing pin. Pad insertion will be skipped for ports that are already connected to such a pin. - clkbuf_sink: marks an input pin as a clock pin, requesting clock buffer insertion. - clkbuf_driver: marks an output pin as a clock buffer output pin. Clock buffer insertion will be skipped for nets that are already driven by such a pin. All three are module attributes that should be set to a comma-separeted list of pin names. Clock buffer insertion itself works as follows: 1. All cell ports, starting from bottom up, can be marked as clock sinks (requesting clock buffer insertion) or as clock buffer outputs. 2. If a wire in a given module is driven by a cell port that is a clock buffer output, it is in turn also considered a clock buffer output. 3. If an input port in a non-top module is connected to a clock sink in a contained cell, it is also in turn considered a clock sink. 4. If a wire in a module is driven by a non-clock-buffer cell, and is also connected to a clock sink port in a contained cell, a clock buffer is inserted in this module. 5. For the top module, a clock buffer is also inserted on input ports connected to clock sinks, optionally with a special kind of input PAD (such as IBUFG for Xilinx). 6. Clock buffer insertion on a given wire is skipped if the clkbuf_inhibit attribute is set on it. |
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| .. | ||
| .gitignore | ||
| abc.cc | ||
| abc9.cc | ||
| aigmap.cc | ||
| alumacc.cc | ||
| attrmap.cc | ||
| attrmvcp.cc | ||
| clkbufmap.cc | ||
| deminout.cc | ||
| dff2dffe.cc | ||
| dff2dffs.cc | ||
| dffinit.cc | ||
| dfflibmap.cc | ||
| dffsr2dff.cc | ||
| extract.cc | ||
| extract_counter.cc | ||
| extract_fa.cc | ||
| extract_reduce.cc | ||
| filterlib.cc | ||
| flowmap.cc | ||
| hilomap.cc | ||
| insbuf.cc | ||
| iopadmap.cc | ||
| libparse.cc | ||
| libparse.h | ||
| lut2mux.cc | ||
| maccmap.cc | ||
| Makefile.inc | ||
| muxcover.cc | ||
| nlutmap.cc | ||
| pmuxtree.cc | ||
| shregmap.cc | ||
| simplemap.cc | ||
| simplemap.h | ||
| techmap.cc | ||
| tribuf.cc | ||
| zinit.cc | ||