[Cryptech-Commits] [staging/core/rng/rosc_entropy] 08/11: Added Xilinx specific constraint attribute to preserve the ring oscillators. Fixed name of rosc instances.

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paul at psgd.org pushed a commit to branch master
in repository staging/core/rng/rosc_entropy.

commit 739bc2f3d81081ef6b75a92d66127fa342453395
Author: Joachim Strömbergson <joachim at secworks.se>
Date:   Thu Oct 23 15:18:42 2014 +0200

    Added Xilinx specific constraint attribute to preserve the ring oscillators. Fixed name of rosc instances.
---
 src/rtl/rosc_entropy_core.v | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/rtl/rosc_entropy_core.v b/src/rtl/rosc_entropy_core.v
index 6fb48ec..eb9dd6e 100644
--- a/src/rtl/rosc_entropy_core.v
+++ b/src/rtl/rosc_entropy_core.v
@@ -104,6 +104,9 @@ module rosc_entropy_core(
   // Wires.
   //----------------------------------------------------------------
   reg           rosc_we;
+
+  // Ugly in-line Xilinx attribute to preserve the registers.
+  (* equivalent_register_removal = "no" *)
   wire [31 : 0] rosc_dout;
 
 
@@ -127,13 +130,13 @@ module rosc_entropy_core(
   generate
     for(i = 0 ; i < 32 ; i = i + 1)
       begin: oscillators
-        rosc #(.WIDTH(1)) osc_array(.clk(clk),
-                                    .we(rosc_we),
-                                    .reset_n(reset_n),
-                                    .opa(opa),
-                                    .opb(opb),
-                                    .dout(rosc_dout[i])
-                                   );
+        rosc #(.WIDTH(1)) rosc_array(.clk(clk),
+                                     .we(rosc_we),
+                                     .reset_n(reset_n),
+                                     .opa(opa),
+                                     .opb(opb),
+                                     .dout(rosc_dout[i])
+                                    );
       end
   endgenerate