ecp5: Fixing 'X' issues with LUT simulation models

Signed-off-by: David Shah <davey1576@gmail.com>

1 files changed, 19 insertions, 6 deletions

diff --git a/techlibs/ecp5/cells_sim.v b/techlibs/ecp5/cells_sim.v
index 1755da24b..cf1446a52 100644
--- a/techlibs/ecp5/cells_sim.v
+++ b/techlibs/ecp5/cells_sim.v
@@ -1,8 +1,11 @@
 // ---------------------------------------
 
 module LUT4(input A, B, C, D, output Z);
-	parameter [15:0] INIT = 16'h0000;
-	assign Z = INIT[{D, C, B, A}];
+    parameter [15:0] INIT = 16'h0000;
+    wire [7:0] s3 = D ?     INIT[15:8] :     INIT[7:0];
+    wire [3:0] s2 = C ?       s3[ 7:4] :       s3[3:0];
+    wire [1:0] s1 = B ?       s2[ 3:2] :       s2[1:0];
+    assign Z =      A ?          s1[1] :         s1[0];
 endmodule
 
 // ---------------------------------------
@@ -22,8 +25,9 @@ module CCU2C(input CIN, A0, B0, C0, D0, A1, B1, C1, D1,
 	parameter INJECT1_1 = "YES";
 
 	// First half
-	wire LUT4_0 = INIT0[{D0, C0, B0, A0}];
-	wire LUT2_0 = INIT0[{2'b00, B0, A0}];
+	wire LUT4_0, LUT2_0;
+	LUT4 #(.INIT(INIT0)) lut4_0(.A(A0), .B(B0), .C(C0), .D(D0), .Z(LUT4_0));
+	LUT2 #(.INIT(INIT0[3:0])) lut2_0(.A(A0), .B(B0), .Z(LUT2_0));
 
 	wire gated_cin_0 = (INJECT1_0 == "YES") ? 1'b0 : CIN;
 	assign S0 = LUT4_0 ^ gated_cin_0;
@@ -32,8 +36,9 @@ module CCU2C(input CIN, A0, B0, C0, D0, A1, B1, C1, D1,
 	wire cout_0 = (~LUT4_0 & gated_lut2_0) | (LUT4_0 & CIN);
 
 	// Second half
-	wire LUT4_1 = INIT1[{D1, C1, B1, A1}];
-	wire LUT2_1 = INIT1[{2'b00, B1, A1}];
+	wire LUT4_1, LUT2_1;
+	LUT4 #(.INIT(INIT1)) lut4_1(.A(A1), .B(B1), .C(C1), .D(D1), .Z(LUT4_1));
+	LUT2 #(.INIT(INIT1[3:0])) lut2_1(.A(A1), .B(B1), .Z(LUT2_1));
 
 	wire gated_cin_1 = (INJECT1_1 == "YES") ? 1'b0 : cout_0;
 	assign S1 = LUT4_1 ^ gated_cin_1;
@@ -190,6 +195,14 @@ endmodule
 
 // ---------------------------------------
 
+module LUT2(input A, B, output Z);
+    parameter [3:0] INIT = 4'h0;
+    wire [1:0] s1 = B ?     INIT[ 3:2] :     INIT[1:0];
+    assign Z =      A ?          s1[1] :         s1[0];
+endmodule
+
+// ---------------------------------------
+
 module TRELLIS_FF(input CLK, LSR, CE, DI, output reg Q);
 	parameter GSR = "ENABLED";
 	parameter [127:0] CEMUX = "1";