[Cryptech-Commits] [test/novena_base] 01/01: Added real prefix detection of sha255 core.

[git at cryptech.is]

This is an automated email from the git hooks/post-receive script.

joachim at secworks.se pushed a commit to branch sha256_core
in repository test/novena_base.

commit f1fe0708e988356413f3160c6a85dc8d82eba3a0
Author: Joachim Strömbergson <joachim at secworks.se>
Date:   Mon Feb 2 20:54:59 2015 +0100

    Added real prefix detection of sha255 core.
---
 rtl/src/verilog/core_selector.v | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/rtl/src/verilog/core_selector.v b/rtl/src/verilog/core_selector.v
index 7f92e43..092b8ca 100644
--- a/rtl/src/verilog/core_selector.v
+++ b/rtl/src/verilog/core_selector.v
@@ -48,12 +48,15 @@ module core_selector
 	 input wire [31 : 0]  write_data
 	);
 
+  parameter SHA256_BASE = 6'h14;
+  wire is_sha256 = ~(sys_eim_addr[13:8] ^ SHA256_BASE);
+  wire sha256_cs = (is_sha256 & sys_eim_rd) | (is_sha256 & sys_eim_wr);
 
   sha256 sha256_inst(
                      .clk(sys_clk),
                      .reset_n(~sys_rst),
 
-                     .cs(sys_eim_rd | sys_eim_wr),
+                     .cs(sha256_cs),
                      .we(sys_eim_wr),
 
                      .address(sys_eim_addr[7 : 0]),