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Once yosys supports "look, don't touch" add annotation to CARRY4_VPR #2068

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litghost opened this issue Mar 3, 2021 · 0 comments

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litghost commented Mar 3, 2021 •

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The xc7 carry de-congestion flow currently has the CARRY4_VPR as a complete blackbox to ABC9. This means that the delay paths through the CARRY4 hard-block are not analysed. This might result in poorer results. Once yosys supports having a "look, don't touch" mode for ABC9 box definitions, add those annotations to CARRY4_VPR here: https://github.com/SymbiFlow/symbiflow-arch-defs/blob/098fe2e8e724bca3902b8121fb254caaed7cb5d3/xc/xc7/techmap/cells_sim.v#L88

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