From d3930ca79eb11952d8e64588e46b0788845997c4 Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Mon, 8 Apr 2019 12:01:06 -0700
Subject: [PATCH] Revert "Remove handling for $pmux, since #895"

This reverts commit aa693d5723ef1438d42cd35a26673703b1eff79f.
---
 passes/techmap/shregmap.cc | 40 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/passes/techmap/shregmap.cc b/passes/techmap/shregmap.cc
index a805ac5a6..39ca60b80 100644
--- a/passes/techmap/shregmap.cc
+++ b/passes/techmap/shregmap.cc
@@ -119,6 +119,22 @@ struct ShregmapTechXilinx7 : ShregmapTech
 				for (auto bit : sigmap(cell->getPort("\\B")))
 					sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, 1, j++);
 			}
+			else if (cell->type == "$pmux") {
+				int width = cell->getParam("\\WIDTH").as_int();
+				int j = 0;
+				for (auto bit : cell->getPort("\\A"))
+					sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, 0, j++);
+				j = cell->getParam("\\S_WIDTH").as_int();
+				int k = 0;
+				for (auto bit : sigmap(cell->getPort("\\B"))) {
+					sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, j, k++);
+					if (k == width) {
+						k = 0;
+						--j;
+					}
+				}
+				log_assert(j == 0);
+			}
 		}
 	}
 
@@ -130,6 +146,8 @@ struct ShregmapTechXilinx7 : ShregmapTech
 		if (cell) {
 			if (cell->type == "$shiftx" && port == "\\A")
 				return;
+			if (cell->type == "$pmux" && (port == "\\A" || port == "\\B"))
+				return;
 			if (cell->type == "$mux" && (port == "\\A" || port == "\\B"))
 				return;
 		}
@@ -181,6 +199,10 @@ struct ShregmapTechXilinx7 : ShregmapTech
 			if (GetSize(taps) != shiftx->getParam("\\A_WIDTH").as_int())
 				return false;
 		}
+		else if (shiftx->type == "$pmux") {
+			if (GetSize(taps) != shiftx->getParam("\\S_WIDTH").as_int() + 1)
+				return false;
+		}
 		else if (shiftx->type == "$mux") {
 			if (GetSize(taps) != 2)
 				return false;
@@ -216,6 +238,24 @@ struct ShregmapTechXilinx7 : ShregmapTech
 			q_wire = shiftx->getPort("\\Y");
 			shiftx->setPort("\\Y", cell->module->addWire(NEW_ID));
 		}
+		else if (shiftx->type == "$pmux") {
+			// Create a new encoder, out of a $pmux, that takes
+			// the existing pmux's 'S' input and transforms it
+			// back into a binary value
+			int clog2taps = ceil(log2(taps.size()));
+			RTLIL::SigSpec b_port;
+			for (int i = shiftx->getParam("\\S_WIDTH").as_int(); i > 0; i--)
+				b_port.append(RTLIL::Const(i, clog2taps));
+			l_wire = cell->module->addWire(NEW_ID, clog2taps);
+			RTLIL::SigSpec s_wire = cell->module->addWire(NEW_ID, shiftx->getParam("\\S_WIDTH").as_int());
+			cell->module->connect(s_wire.extract(0, shiftx->getParam("\\S_WIDTH").as_int()), shiftx->getPort("\\S"));
+			cell->module->addPmux(NEW_ID, RTLIL::Const(0, clog2taps), b_port, s_wire, l_wire);
+			int group = std::get<2>(it->second);
+			RTLIL::SigSpec y_wire = shiftx->getPort("\\Y");
+			q_wire = y_wire[group];
+			y_wire[group] = cell->module->addWire(NEW_ID);
+			shiftx->setPort("\\Y", y_wire);
+		}
 		else if (shiftx->type == "$mux") {
 			l_wire = shiftx->getPort("\\S");
 			q_wire = shiftx->getPort("\\Y");
-- 
2.30.2