From f1579304a6e59f832e24fe9cfea6509cbdd6398b Mon Sep 17 00:00:00 2001
From: Lofty <dan.ravensloft@gmail.com>
Date: Sat, 18 Oct 2025 12:10:50 +0100
Subject: [PATCH] analogdevices: DSP tweaks

---
 techlibs/analogdevices/cells_sim.v            | 13 ++++++++++---
 techlibs/analogdevices/synth_analogdevices.cc |  2 +-
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/techlibs/analogdevices/cells_sim.v b/techlibs/analogdevices/cells_sim.v
index 573259472..402c421fa 100644
--- a/techlibs/analogdevices/cells_sim.v
+++ b/techlibs/analogdevices/cells_sim.v
@@ -1014,6 +1014,7 @@ endmodule
 
 // DSP
 
+(* abc9_box *)
 module RBBDSP (
   output [21:0] AO_LOC,
   output [21:0] BO_LOC,
@@ -1025,9 +1026,9 @@ module RBBDSP (
   output [47:0] PO_LOC,
   output        RST_O,
 
-  input  [1:0] CI_LOC,
-  input  [1:0] OPCODE,
-  input  [1:0] OPCODE_I,
+  input  [1:0]  CI_LOC,
+  input  [1:0]  OPCODE,
+  input  [1:0]  OPCODE_I,
   input  [21:0] A,
   input  [21:0] AI_LOC,
   input  [21:0] B,
@@ -1087,6 +1088,12 @@ parameter REG_SFT = 1'b0;
 parameter RST_SEL = 1'b0;
 parameter FF_SYNC_RST = 1'b0;
 
+specify
+  if (!REG_A)    (A *> P) = 1000;
+  if (!REG_B)    (B *> P) = 1000;
+  if (!REG_D[0]) (D *> P) = 1000;
+endspecify
+
 // Much of this functionality is TODO.
 
 assign P = $signed(A) * $signed(B);
diff --git a/techlibs/analogdevices/synth_analogdevices.cc b/techlibs/analogdevices/synth_analogdevices.cc
index c6514d4aa..18619de7a 100644
--- a/techlibs/analogdevices/synth_analogdevices.cc
+++ b/techlibs/analogdevices/synth_analogdevices.cc
@@ -313,7 +313,7 @@ struct SynthAnalogDevicesPass : public ScriptPass
 		if (check_label("map_dsp", "(skip if '-nodsp')")) {
 			if (!nodsp || help_mode) {
 				run("memory_dff"); // xilinx_dsp will merge registers, reserve memory port registers first
-				// NB: Xilinx multipliers are signed only
+				// NB: Analog Devices multipliers are signed only
 				if (help_mode)
 					run("techmap -map +/mul2dsp.v -map +/analogdevices/{family}_dsp_map.v {options}");
 				run("techmap -map +/mul2dsp.v -map +/analogdevices/dsp_map.v -D DSP_A_MAXWIDTH=22 -D DSP_B_MAXWIDTH=22 "