mirror of https://github.com/YosysHQ/yosys.git
fc28bf55aa
This commit tries to carefully follow the documented behavior of LSE
and Synplify. It will use `syn_ramstyle` attribute if there are any
write ports, and `syn_romstyle` attribute otherwise.
* LSE supports both `syn_ramstyle` and `syn_romstyle`.
* Synplify only supports `syn_ramstyle`, with same values as LSE.
* Synplify also supports `syn_rw_conflict_logic`, which is not
documented as supported for LSE.
Limitations of the Yosys implementation:
* LSE/Synplify appear to interpret attribute values insensitive
to case. There is currently no way to do this in Yosys (attrmap
can only change case of attribute names).
* LSE/Synplify support `syn_ramstyle="block_ram,no_rw_check"`
syntax to turn off insertion of transparency logic. There is
currently no way to support multiple valued attributes in
memory_bram. It is also not clear if that is a good idea, since
it can cause sim/synth mismatches.
* LSE/Synplify/1364.1 support block ROM inference from full case
statements. Yosys does not currently perform this transformation.
* LSE/Synplify propagate `syn_ramstyle`/`syn_romstyle` attributes
from the module to the inner memories. There is currently no way
to do this in Yosys (attrmvcp only works on cells and wires).
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| .. | ||
| aiger | ||
| arch | ||
| asicworld | ||
| bram | ||
| errors | ||
| fsm | ||
| hana | ||
| liberty | ||
| lut | ||
| memories | ||
| opt | ||
| opt_share | ||
| proc | ||
| realmath | ||
| rpc | ||
| sat | ||
| share | ||
| simple | ||
| simple_abc9 | ||
| smv | ||
| sva | ||
| svinterfaces | ||
| svtypes | ||
| techmap | ||
| tools | ||
| unit | ||
| various | ||
| vloghtb | ||