From 390cf34d0a8f815ea9828f9a455b36164f9d5607 Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Fri, 30 Aug 2019 15:00:56 -0700
Subject: [PATCH] Add support for ffM

---
 passes/pmgen/xilinx_dsp.cc  | 12 ++++++++++++
 passes/pmgen/xilinx_dsp.pmg | 39 ++++++++++++++++++++++++++++++++++---
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/passes/pmgen/xilinx_dsp.cc b/passes/pmgen/xilinx_dsp.cc
index e7b72e312..105ad1fa1 100644
--- a/passes/pmgen/xilinx_dsp.cc
+++ b/passes/pmgen/xilinx_dsp.cc
@@ -39,6 +39,7 @@ void pack_xilinx_dsp(dict<SigBit, Cell*> &bit_to_driver, xilinx_dsp_pm &pm)
 	log("ffB:     %s\n", log_id(st.ffB, "--"));
 	log("dsp:     %s\n", log_id(st.dsp, "--"));
 	log("addAB:   %s\n", log_id(st.addAB, "--"));
+	log("ffM:     %s\n", log_id(st.ffM, "--"));
 	log("ffP:     %s\n", log_id(st.ffP, "--"));
 	//log("muxP:  %s\n", log_id(st.muxP, "--"));
 	log("sigPused: %s\n", log_signal(st.sigPused));
@@ -95,6 +96,17 @@ void pack_xilinx_dsp(dict<SigBit, Cell*> &bit_to_driver, xilinx_dsp_pm &pm)
 			//	cell->setPort("\\CEB2", st.ffB->getPort("\\EN"));
 			else log_abort();
 		}
+		if (st.ffM) {
+			SigSpec D = st.ffM->getPort("\\D");
+			SigSpec Q = st.ffM->getPort("\\Q");
+			P.replace(pm.sigmap(D), Q);
+			cell->setParam("\\MREG", State::S1);
+			if (st.ffP->type == "$dff")
+				cell->setPort("\\CEM", State::S1);
+			//else if (st.ffP->type == "$dffe")
+			//	cell->setPort("\\CEP", st.ffP->getPort("\\EN"));
+			else log_abort();
+		}
 		if (st.ffP) {
 			SigSpec D;
 			//if (st.muxP)
diff --git a/passes/pmgen/xilinx_dsp.pmg b/passes/pmgen/xilinx_dsp.pmg
index 47e6a0050..08b432b8e 100644
--- a/passes/pmgen/xilinx_dsp.pmg
+++ b/passes/pmgen/xilinx_dsp.pmg
@@ -2,7 +2,7 @@ pattern xilinx_dsp
 
 state <SigBit> clock
 state <std::set<SigBit>> sigAset sigBset
-state <SigSpec> sigC sigP sigPused
+state <SigSpec> sigC sigM sigMused sigP sigPused
 state <Cell*> addAB
 
 match dsp
@@ -18,6 +18,12 @@ code sigAset sigBset
 	sigBset = B.to_sigbit_set();
 endcode
 
+code sigM
+	sigM = port(dsp, \P);
+	//if (GetSize(sigH) <= 10)
+	//	reject;
+endcode
+
 match ffA
 	if param(dsp, \AREG).as_int() == 0
 	if !sigAset.empty()
@@ -63,8 +69,35 @@ code clock
 	}
 endcode
 
-code sigP
-	sigP = port(dsp, \P);
+match ffM
+	if param(dsp, \MREG).as_int() == 0
+	select ffM->type.in($dff)
+	// DSP48E1 does not support clock inversion
+	select param(ffM, \CLK_POLARITY).as_bool()
+	select nusers(port(ffM, \D)) == 2
+	//index <SigSpec> port(ffM, \D) === sigM.extract(0, GetSize(port(ffM, \D))) // TODO: Why doesn't this work!?!
+	filter port(ffM, \D) == sigM.extract(0, GetSize(port(ffM, \D)))
+    filter nusers(sigM.extract_end(param(ffM, \WIDTH).as_int())) == 1
+	optional
+endmatch
+
+code clock sigM sigP
+	if (ffM) {
+        log_warning("M FOUND!\n");
+		sigM = port(ffM, \Q);
+		for (auto b : sigM)
+			if (b.wire->get_bool_attribute(\keep))
+				reject;
+
+		SigBit c = port(ffB, \CLK).as_bit();
+
+		if (clock != SigBit() && c != clock)
+			reject;
+
+		clock = c;
+	}
+
+	sigP = sigM;
 endcode
 
 match addA
-- 
2.30.2