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ice40: Explicitly connect CIN when legalizing carry chain 

This connection is implicit as it is hardwired in the hardware.
This commit makes the connection explicit and thus appearing in the
generated netlist allowing post-rout simulation.
This commit is contained in:
TG 2025-12-02 08:58:19 +01:00 committed by Marcelina Kościelnicka
parent cfa5f77dd9
commit c46f2bbd86
1 changed files with 2 additions and 0 deletions
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2
ice40/chains.cc
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@ -122,6 +122,8 @@ class ChainConstrainer
o_r.cell = lc.get(); o_r.cell = lc.get();
cout_port.net->driver = o_r; cout_port.net->driver = o_r;
cout_port.net = co_i3_net; cout_port.net = co_i3_net;
// CIN is connected to COUT in hardware, make the connection explicit in the netlist
lc->connectPort(id_CIN, co_i3_net);
// If COUT also connects to a CIN; preserve the carry chain // If COUT also connects to a CIN; preserve the carry chain
if (cin_cell) { if (cin_cell) {