techmap: Add support for extracting init values of ports

1 files changed, 98 insertions, 0 deletions

diff --git a/tests/techmap/wireinit.ys b/tests/techmap/wireinit.ys
new file mode 100644
index 000000000..1396839fe
--- /dev/null
+++ b/tests/techmap/wireinit.ys
@@ -0,0 +1,98 @@
+read_verilog <<EOT
+(* techmap_celltype = "$_DFF_P_" *)
+module ffmap(...);
+input D;
+input C;
+output Q;
+parameter [0:0] _TECHMAP_WIREINIT_Q_ = 1'bx;
+
+ffbb #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_(.D(D), .Q(Q), .C(C));
+
+wire _TECHMAP_FAIL_ = _TECHMAP_WIREINIT_Q_ === 1'b1;
+
+wire _TECHMAP_REMOVEINIT_Q_ = 1'b1;
+
+endmodule
+EOT
+design -stash map
+
+read_verilog <<EOT
+(* techmap_celltype = "$_DFF_P_" *)
+module ffmap(...);
+input D;
+input C;
+output Q;
+parameter [0:0] _TECHMAP_WIREINIT_Q_ = 1'bx;
+
+ffbb #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_(.D(D), .Q(Q), .C(C));
+
+wire _TECHMAP_FAIL_ = _TECHMAP_WIREINIT_Q_ === 1'b1;
+
+wire _TECHMAP_REMOVEINIT_Q_ = 1'b0;
+
+endmodule
+EOT
+design -stash map_noremove
+
+read_verilog <<EOT
+module ffbb (...);
+parameter [0:0] INIT = 1'bx;
+input D, C;
+output Q;
+endmodule
+
+module top(...);
+input clk;
+input d;
+output reg q0 = 0;
+output reg q1 = 1;
+output reg qx;
+
+always @(posedge clk) begin
+	q0 <= d;
+	q1 <= d;
+	qx <= d;
+end
+endmodule
+EOT
+
+design -save ref
+
+hierarchy -auto-top
+proc
+simplemap
+techmap -map %map
+clean
+# Make sure the parameter was used properly.
+select -assert-count 2 top/t:ffbb
+select -set ff0 top/w:q0 %ci t:ffbb %i
+select -set ffx top/w:qx %ci t:ffbb %i
+select -assert-count 1 @ff0
+select -assert-count 1 @ffx
+select -assert-count 1 @ff0 r:INIT=1'b0 %i
+select -assert-count 1 @ffx r:INIT=1'bx %i
+select -assert-count 0 top/w:q1 %ci t:ffbb %i
+# Make sure the init values are dropped from the wires iff mapping was performed.
+select -assert-count 0 top/w:q0 a:init %i
+select -assert-count 1 top/w:q1 a:init=1'b1 %i
+select -assert-count 0 top/w:qx a:init %i
+
+design -load ref
+hierarchy -auto-top
+proc
+simplemap
+techmap -map %map_noremove
+clean
+# Make sure the parameter was used properly.
+select -assert-count 2 top/t:ffbb
+select -set ff0 top/w:q0 %ci t:ffbb %i
+select -set ffx top/w:qx %ci t:ffbb %i
+select -assert-count 1 @ff0
+select -assert-count 1 @ffx
+select -assert-count 1 @ff0 r:INIT=1'b0 %i
+select -assert-count 1 @ffx r:INIT=1'bx %i
+select -assert-count 0 top/w:q1 %ci t:ffbb %i
+# Make sure the init values are not dropped from the wires.
+select -assert-count 1 top/w:q0 a:init=1'b0 %i
+select -assert-count 1 top/w:q1 a:init=1'b1 %i
+select -assert-count 0 top/w:qx a:init %i