From a459eb70a9271efc472dc047198c9722445780fe Mon Sep 17 00:00:00 2001
From: Roland Coeurjoly <rolandcoeurjoly@gmail.com>
Date: Sun, 7 Jul 2024 23:16:34 +0200
Subject: [PATCH] bmux works for SMT, simulation fails for C++

---
 kernel/functionalir.cc | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/kernel/functionalir.cc b/kernel/functionalir.cc
index 6498ef63629..eb427d2ed55 100644
--- a/kernel/functionalir.cc
+++ b/kernel/functionalir.cc
@@ -249,8 +249,30 @@ class CellSimplifier {
 			}
 		} else if(cellType == ID($pow)) {
 			return handle_pow(inputs.at(ID(A)), a_width, inputs.at(ID(B)), b_width, y_width, a_signed && b_signed);
+		} else if (cellType == ID($bmux)) {
+		  int width = parameters.at(ID(WIDTH)).as_int();
+		  int s_width = parameters.at(ID(S_WIDTH)).as_int();
+		  T a = inputs.at(ID(A));
+		  T s = inputs.at(ID(S));
+
+		  // Initialize the result with the first slice of A
+		  T result = factory.slice(a, 0, width, width);
+
+		  for (int i = 1; i < (1 << s_width); i++) {
+		    // Compute the current slice of A
+		    T current_slice = factory.slice(a, i * width, width, width);
+        
+		    // Compute the select signal for the current slice
+		    RTLIL::Const const_i(i, s_width);
+		    T current_select = factory.equal(s, factory.constant(const_i), s_width);
+        
+		    // Update the result based on the current select signal
+		    result = factory.mux(result, current_slice, current_select, width);
+		  }
+
+		  return result;
 		} else{
-			log_error("unhandled cell in CellSimplifier %s\n", cellType.c_str());
+		  log_error("unhandled cell in CellSimplifier %s\n", cellType.c_str());
 		}
 	}
 };