From ef2488e4059b70921c0cd376cf40683ed3cb5dbf Mon Sep 17 00:00:00 2001
From: gatecat <gatecat@ds0.me>
Date: Mon, 16 Mar 2026 09:38:16 +0000
Subject: [PATCH] xilinx: Index control sets

Signed-off-by: gatecat <gatecat@ds0.me>
---
 himbaechel/uarch/xilinx/xilinx.cc | 46 ++++++++++++++++++++++++++++++-
 himbaechel/uarch/xilinx/xilinx.h  |  2 ++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/himbaechel/uarch/xilinx/xilinx.cc b/himbaechel/uarch/xilinx/xilinx.cc
index ad41cdbd..18271674 100644
--- a/himbaechel/uarch/xilinx/xilinx.cc
+++ b/himbaechel/uarch/xilinx/xilinx.cc
@@ -39,6 +39,30 @@
 
 NEXTPNR_NAMESPACE_BEGIN
 
+
+struct FFControlSet
+{
+    unsigned flags = 0;
+    enum {
+        IS_LATCH = 1,
+        IS_CLKINV = 2,
+        IS_SRINV = 4,
+        FFSYNC = 8,
+    };
+    IdString clk, sr, ce;
+    bool operator==(const FFControlSet &other) const {
+        return flags == other.flags && clk == other.clk
+            && ce == other.ce && sr == other.sr;
+    };
+    unsigned hash() const {
+        unsigned hash = mkhash(clk.hash(), sr.hash());
+        hash = mkhash(hash, ce.hash());
+        hash = mkhash(hash, flags);
+        return hash;
+    }
+};
+
+
 XilinxImpl::~XilinxImpl() {};
 
 po::options_description XilinxImpl::getUArchOptions()
@@ -274,7 +298,7 @@ bool XilinxImpl::is_pip_unavail(PipId pip) const
     return false;
 }
 
-void XilinxImpl::prePlace() { assign_cell_tags(); }
+void XilinxImpl::prePlace() { assign_cell_tags(); index_control_sets(); }
 
 void XilinxImpl::postPlace()
 {
@@ -542,6 +566,26 @@ void XilinxImpl::assign_cell_tags()
     }
 }
 
+void XilinxImpl::index_control_sets() {
+    idict<FFControlSet> control_sets;
+    for (auto &cell : ctx->cells) {
+        CellInfo *ci = cell.second.get();
+        if (ci->type == id_SLICE_FFX) {
+            auto &ct = cell_tags.at(ci->flat_index);
+            FFControlSet ctrl_set;
+            ctrl_set.clk = ct.ff.clk ? ct.ff.clk->name : IdString();
+            ctrl_set.ce = ct.ff.ce ? ct.ff.ce->name : IdString();
+            ctrl_set.sr = ct.ff.clk ? ct.ff.sr->name : IdString();
+            ctrl_set.flags = (ct.ff.is_clkinv ? FFControlSet::IS_CLKINV : 0) |
+                 (ct.ff.is_srinv ? FFControlSet::IS_SRINV : 0) |
+                 (ct.ff.is_latch ? FFControlSet::IS_LATCH : 0) |
+                 (ct.ff.ffsync ? FFControlSet::FFSYNC : 0);
+            ct.ff.control_set = control_sets(ctrl_set);
+        }
+    }
+    log_info("Indexed %d control sets.\n", int(control_sets.size()));
+}
+
 bool XilinxImpl::is_general_routing(WireId wire) const
 {
     IdString intent = ctx->getWireType(wire);
diff --git a/himbaechel/uarch/xilinx/xilinx.h b/himbaechel/uarch/xilinx/xilinx.h
index ceaa2c87..434d85c5 100644
--- a/himbaechel/uarch/xilinx/xilinx.h
+++ b/himbaechel/uarch/xilinx/xilinx.h
@@ -49,6 +49,7 @@ struct XilinxCellTags
             bool is_latch, is_clkinv, is_srinv, ffsync;
             bool is_paired;
             NetInfo *clk, *sr, *ce, *d;
+            int32_t control_set;
         } ff;
         struct
         {
@@ -183,6 +184,7 @@ struct XilinxImpl : HimbaechelAPI
   private:
     HimbaechelHelpers h;
     void assign_cell_tags();
+    void index_control_sets();
 };
 
 NEXTPNR_NAMESPACE_END