From 07e50b9c256358b2800a5272258a083f7e4d67d3 Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Thu, 8 Aug 2019 10:51:19 -0700
Subject: [PATCH] Only pack registers if {A,B,P}REG = 0, do not pack $dffe

---
 passes/pmgen/xilinx_dsp.pmg | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/passes/pmgen/xilinx_dsp.pmg b/passes/pmgen/xilinx_dsp.pmg
index a97ab4dd5..6fd1207fa 100644
--- a/passes/pmgen/xilinx_dsp.pmg
+++ b/passes/pmgen/xilinx_dsp.pmg
@@ -8,9 +8,10 @@ match dsp
 endmatch
 
 match ffA
-	select ffA->type.in($dff, $dffe)
+	select ffA->type.in($dff)
 	// DSP48E1 does not support clock inversion
 	select param(ffA, \CLK_POLARITY).as_bool()
+	filter param(dsp, \AREG).as_int() == 0
 	filter !port(dsp, \A).remove_const().empty()
 	filter includes(port(ffA, \Q).to_sigbit_set(), port(dsp, \A).remove_const().to_sigbit_set())
 	optional
@@ -22,9 +23,10 @@ code clock
 endcode
 
 match ffB
-	select ffB->type.in($dff, $dffe)
+	select ffB->type.in($dff)
 	// DSP48E1 does not support clock inversion
 	select param(ffB, \CLK_POLARITY).as_bool()
+	filter param(dsp, \BREG).as_int() == 0
 	filter !port(dsp, \B).remove_const().empty()
 	filter includes(port(ffB, \Q).to_sigbit_set(), port(dsp, \B).remove_const().to_sigbit_set())
 	optional
@@ -54,10 +56,11 @@ endcode
 
 match ffP
 	if !sigPused.empty()
-	select ffP->type.in($dff, $dffe)
+	select ffP->type.in($dff)
 	select nusers(port(ffP, \D)) == 2
 	// DSP48E1 does not support clock inversion
 	select param(ffP, \CLK_POLARITY).as_bool()
+	filter param(dsp, \PREG).as_int() == 0
 	filter param(ffP, \WIDTH).as_int() >= GetSize(sigPused)
 	filter includes(port(ffP, \D).to_sigbit_set(), sigPused.to_sigbit_set())
 	optional
-- 
2.30.2