build.xilinx: Convert attributes to something Yosys understands.
authorTim 'mithro' Ansell <me@mith.ro>
Fri, 5 Oct 2018 19:48:30 +0000 (12:48 -0700)
committerTim 'mithro' Ansell <me@mith.ro>
Fri, 5 Oct 2018 19:48:30 +0000 (12:48 -0700)
commitace976242e7a9da21fbcf59e2bd5999c8b610789
tree4ac966f3f30ce75ceb951960f2cd902b2b093864
parent78414c05888ebc8198fc059567eb5e7db3a8f38f
build.xilinx: Convert attributes to something Yosys understands.

Convert keep, dont_touch and async_reg to something Yosys understands.

Write out an EDIF file with the attributes so that Vivado can use them.
(Requires Yosys with commit
https://github.com/YosysHQ/yosys/commit/115ca576475a2e8d30e63b339ae6a1b5db6906a6)
litex/build/xilinx/common.py