Started working on the pipelined Montgomery modular multiplier. Currently can

do the "square" part of the multiplication, i.e. compute the twice larger
intermediate product AB = A * B.

1 files changed, 35 insertions, 0 deletions

diff --git a/rtl/modexpng_recombinator_block.v b/rtl/modexpng_recombinator_block.v
new file mode 100644
index 0000000..efe0ac5
--- /dev/null
+++ b/rtl/modexpng_recombinator_block.v
@@ -0,0 +1,35 @@
+module modexpng_recombinator_block
+(
+    clk,
+    ce, clr,
+    din, dout
+);
+
+    input         clk;
+    input         ce;
+    input         clr;
+    input  [46:0] din;
+    output [15:0] dout;
+
+    reg [14:0] z;
+    reg [16:0] y;
+    reg [17:0] x;
+    //reg [15:0] w;
+
+    //assign dout = w;
+    assign dout = x[15:0];
+    
+    wire [14:0] din_z = din[46:32]; // TODO: maybe determine more precise bound here
+    wire [15:0] din_y = din[31:16];
+    wire [15:0] din_x = din[15: 0];
+    
+    always @(posedge clk)
+        //
+        if (ce) begin
+            z <= din_z;
+            y <= clr ? {1'b0, din_y}  : {1'b0, din_y} + {2'b00, z};
+            x <= clr ? {2'b00, din_x} : {2'b00, din_x} + {1'b0, y} + {{16{1'b0}}, x[17:16]};
+            //w <= clr ? {16{1'bX}}     : x[15:0];        
+        end
+    
+endmodule