From 9e9689d7b00ecdcc1c651f5e369e00a53d62df3c Mon Sep 17 00:00:00 2001
From: "Pavel V. Shatov (Meister)" <meisterpaul1@yandex.ru>
Date: Tue, 1 Oct 2019 15:05:11 +0300
Subject: Further work on the Montgomery modular multiplier. Can now to the
 "triangular" part of multiplication, i.e. compute the "magic" reduction
 coefficient Q = LSB(AB) * N_COEFF.

---
 rtl/dsp/dsp_array.v | 42 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

(limited to 'rtl/dsp/dsp_array.v')

diff --git a/rtl/dsp/dsp_array.v b/rtl/dsp/dsp_array.v
index 178f87f..2a050d4 100644
--- a/rtl/dsp/dsp_array.v
+++ b/rtl/dsp/dsp_array.v
@@ -8,11 +8,11 @@ module dsp_array
     input             ce_p,
     input             ce_mode,
 
-    input  [8   -1:0] mode_z,
+    input  [9   -1:0] mode_z,
     
-    input  [4*18-1:0] a,
+    input  [5*18-1:0] a,
     input  [1*17-1:0] b,
-    output [8*47-1:0] p
+    output [9*47-1:0] p
 );
 
     `include "../modexpng_parameters_x8.vh"
@@ -37,7 +37,7 @@ module dsp_array
     genvar z;
     generate for (z=0; z<(NUM_MULTS/2); z=z+1)
         //
-        begin : DSP48E1
+        begin : gen_DSP48E1
             //        
             dsp_slice #
             (
@@ -64,7 +64,7 @@ module dsp_array
                 .opmode         ({1'b0, mode_z[2*z], 1'b0, 2'b01, 2'b01}),
                 .alumode        (4'b0000),
                 
-                .casc_a_in      ({17{1'b0}}),
+                .casc_a_in      ({18{1'b0}}),
                 .casc_b_in      ({17{1'b0}}),
                 
                 .casc_a_out     (casc_a[z]),
@@ -107,5 +107,37 @@ module dsp_array
         //
     endgenerate
 
+    dsp_slice #
+    (
+        .AB_INPUT("DIRECT"),
+        .B_REG(2)
+    )
+    dsp_aux
+    (
+        .clk            (clk),
+        
+        .ce_a1          (ce_a0),
+        .ce_b1          (ce_b0),
+        .ce_a2          (ce_a1),
+        .ce_b2          (ce_b1),
+        .ce_m           (ce_m),
+        .ce_p           (ce_p),
+        .ce_mode        (ce_mode),
+        
+        .a              (a[4*18+:18]),
+        .b              (b),
+        .p              (p[47*2*4+:47]),
+        
+        .inmode         (5'b00000),
+        .opmode         ({1'b0, mode_z[2*4], 1'b0, 2'b01, 2'b01}),
+        .alumode        (4'b0000),
+        
+        .casc_a_in      ({18{1'b0}}),
+        .casc_b_in      ({17{1'b0}}),
+        
+        .casc_a_out     (),
+        .casc_b_out     ()
+    );
+
 
 endmodule
-- 
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