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-rw-r--r--ice40/bitstream.cc3
-rw-r--r--ice40/place_legaliser.cc17
2 files changed, 19 insertions, 1 deletions
diff --git a/ice40/bitstream.cc b/ice40/bitstream.cc
index 942c9977..1a498dd1 100644
--- a/ice40/bitstream.cc
+++ b/ice40/bitstream.cc
@@ -178,7 +178,8 @@ void write_asc(const Context *ctx, std::ostream &out)
bool carry_const = get_param_or_def(cell.second.get(), ctx->id("CIN_CONST"));
bool carry_set = get_param_or_def(cell.second.get(), ctx->id("CIN_SET"));
if (carry_const) {
- assert(z == 0);
+ if (!ctx->force)
+ assert(z == 0);
set_config(ti, config.at(y).at(x), "CarryInSet", carry_set);
}
} else if (cell.second->type == ctx->id("SB_IO")) {
diff --git a/ice40/place_legaliser.cc b/ice40/place_legaliser.cc
index 1292d094..91350c2b 100644
--- a/ice40/place_legaliser.cc
+++ b/ice40/place_legaliser.cc
@@ -155,6 +155,22 @@ class PlacementLegaliser
return i3_next;*/
return (CellInfo *)nullptr;
});
+ std::unordered_set<IdString> chained;
+ for (auto &base_chain : carry_chains) {
+ for (auto c : base_chain.cells)
+ chained.insert(c->name);
+ }
+ // Any cells not in chains, but with carry enabled, must also be put in a single-carry chain
+ // for correct processing
+ for (auto cell : sorted(ctx->cells)) {
+ CellInfo *ci = cell.second;
+ if (chained.find(cell.first) == chained.end() && is_lc(ctx, ci) && bool_or_default(ci->params, ctx->id("CARRY_ENABLE"))) {
+ CellChain sChain;
+ sChain.cells.push_back(ci);
+ chained.insert(cell.first);
+ carry_chains.push_back(sChain);
+ }
+ }
bool success = true;
// Find midpoints for all chains, before we start tearing them up
std::vector<CellChain> all_chains;
@@ -274,6 +290,7 @@ class PlacementLegaliser
CellInfo *passout = make_carry_pass_out(cell->ports.at(ctx->id("COUT")));
chains.back().cells.push_back(passout);
tile.push_back(passout);
+ start_of_chain = true;
}
}
++curr_cell;