Using "via_celltype" in $mul carry-save-acc implementation

diff --git a/techlibs/common/techmap.v b/techlibs/common/techmap.v
index 366351ec0633248ffd9bf5705a23df0ba28e8315..1486b801e2059357e048321992f33fc774beac52 100644 (file)
--- a/techlibs/common/techmap.v
+++ b/techlibs/common/techmap.v
@@ -465,62 +465,98 @@ endmodule
 // Multiply
 // --------------------------------------------------------
 
-module \$__arraymul (A, B, Y);
-       parameter WIDTH = 8;
+module \$__acc_set (acc_new, value);
+       parameter WIDTH = 1;
+       output reg [2*WIDTH-1:0] acc_new;
+       input [WIDTH-1:0] value;
+
+       wire [1023:0] _TECHMAP_DO_ = "proc;;;";
+
+       integer k;
+       always @* begin
+               for (k = 0; k < WIDTH; k = k+1) begin
+                       acc_new[2*k +: 2] = value[k];
+               end
+       end
+endmodule
+
+module \$__acc_add (acc_new, acc_old, value);
+       parameter WIDTH = 1;
+       output reg [2*WIDTH-1:0] acc_new;
+       input [2*WIDTH-1:0] acc_old;
+       input [WIDTH-1:0] value;
+
+       wire [1023:0] _TECHMAP_DO_ = "proc; simplemap; opt -purge";
+
+       integer k;
+       reg a, b, c;
+
+       always @* begin
+               for (k = 0; k < WIDTH; k = k+1) begin
+                       a = acc_old[2*k];
+                       b = k ? acc_old[2*k-1] : 1'b0;
+                       c = value[k];
+                       acc_new[2*k] = (a ^ b) ^ c;
+                       acc_new[2*k+1] = (a & b) | ((a ^ b) & c);
+               end
+       end
+endmodule
+
+module \$__acc_get (value, acc);
+       parameter WIDTH = 1;
+       output reg [WIDTH-1:0] value;
+       input [2*WIDTH-1:0] acc;
+
+       wire [1023:0] _TECHMAP_DO_ = "proc;;;";
+
+       integer k;
+
+       always @* begin
+               // at the end of the multiplier chain the carry-save accumulator
+               // should also have propagated all carries. thus we just need to
+               // copy the even bits from the carry accumulator to the output.
+               for (k = 0; k < WIDTH; k = k+1) begin
+                       value[k] = acc[2*k];
+               end
+       end
+endmodule
+
+module \$__acc_mul (A, B, Y);
+       parameter WIDTH = 1;
        input [WIDTH-1:0] A, B;
        output [WIDTH-1:0] Y;
 
-       wire [1023:0] _TECHMAP_DO_ = "proc;; opt";
+       wire [1023:0] _TECHMAP_DO_ = "proc;;";
 
        integer i;
        reg [WIDTH-1:0] x;
        reg [2*WIDTH-1:0] y;
 
+       (* via_celltype = "\\$__acc_set acc_new" *)
+       (* via_celltype_defparam_WIDTH = WIDTH *)
        function [2*WIDTH-1:0] acc_set;
                input [WIDTH-1:0] value;
-               integer k;
-               begin
-                       for (k = 0; k < WIDTH; k = k+1) begin
-                               acc_set[2*k +: 2] = value[k];
-                       end
-               end
        endfunction
 
+       (* via_celltype = "\\$__acc_add acc_new" *)
+       (* via_celltype_defparam_WIDTH = WIDTH *)
        function [2*WIDTH-1:0] acc_add;
-               input [2*WIDTH-1:0] old_acc;
+               input [2*WIDTH-1:0] acc_old;
                input [WIDTH-1:0] value;
-               integer k;
-               reg a, b, c;
-               begin
-                       for (k = 0; k < WIDTH; k = k+1) begin
-                               a = old_acc[2*k];
-                               b = k ? old_acc[2*k-1] : 1'b0;
-                               c = value[k];
-                               acc_add[2*k] = (a ^ b) ^ c;
-                               acc_add[2*k+1] = (a & b) | ((a ^ b) & c);
-                       end
-               end
        endfunction
 
+       (* via_celltype = "\\$__acc_get value" *)
+       (* via_celltype_defparam_WIDTH = WIDTH *)
        function [WIDTH-1:0] acc_get;
                input [2*WIDTH-1:0] acc;
-               integer k;
-               begin
-                       // at the end of the multiplier chain the carry-save accumulator
-                       // should also have propagated all carries. thus we just need to
-                       // copy the even bits from the carry accumulator to the output.
-                       for (k = 0; k < WIDTH; k = k+1) begin
-                               acc_get[k] = acc[2*k];
-                       end
-               end
        endfunction
 
        always @* begin
                x = B;
-               y = acc_set(A[0] ? x : 0);
+               y = acc_set(A[0] ? x : 1'b0);
                for (i = 1; i < WIDTH; i = i+1) begin
                        x = {x[WIDTH-2:0], 1'b0};
-                       y = acc_add(y, A[i] ? x : 0);
+                       y = acc_add(y, A[i] ? x : 1'b0);
                end
        end
 
@@ -538,13 +574,15 @@ module \$mul (A, B, Y);
        input [B_WIDTH-1:0] B;
        output [Y_WIDTH-1:0] Y;
 
+       wire [1023:0] _TECHMAP_DO_ = "RECURSION; CONSTMAP; opt -purge";
+
        wire [Y_WIDTH-1:0] A_buf, B_buf;
        \$pos #(.A_SIGNED(A_SIGNED), .A_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) A_conv (.A(A), .Y(A_buf));
        \$pos #(.A_SIGNED(B_SIGNED), .A_WIDTH(B_WIDTH), .Y_WIDTH(Y_WIDTH)) B_conv (.A(B), .Y(B_buf));
 
-       \$__arraymul #(
+       \$__acc_mul #(
                .WIDTH(Y_WIDTH)
-       ) arraymul (
+       ) _TECHMAP_REPLACE_ (
                .A(A_buf),
                .B(B_buf),
                .Y(Y)