[Cryptech-Commits] [core/platform/common] 01/01: Fixed incorrect bitwidth of address to modexp core. Removed address block defines that are internal to the modexp core. Now the modexp core does not get optimized away.

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joachim at secworks.se pushed a commit to branch master
in repository core/platform/common.

commit e34b409d8f01b0fe8b24b3cf8defa29bddc29ead
Author: Joachim Strömbergson <joachim at secworks.se>
Date:   Fri May 8 13:51:51 2015 +0200

    Fixed incorrect bitwidth of address to modexp core. Removed address block defines that are internal to the modexp core. Now the modexp core does not get optimized away.
---
 core_selector/src/rtl/math_selector.v | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/core_selector/src/rtl/math_selector.v b/core_selector/src/rtl/math_selector.v
index 93fc8d2..b47a433 100644
--- a/core_selector/src/rtl/math_selector.v
+++ b/core_selector/src/rtl/math_selector.v
@@ -57,10 +57,10 @@ module math_selector
    //----------------------------------------------------------------
    // Address Decoder
    //----------------------------------------------------------------
-   // upper 6 bits specify core being addressed
-   wire [ 5: 0]         addr_core_num   = sys_eim_addr[13: 8];
-   // lower 8 bits specify register offset in core
-   wire [ 7: 0]         addr_core_reg   = sys_eim_addr[ 7: 0];
+   // upper 2 bits specify core being addressed
+   wire [ 1: 0]         core_select = sys_eim_addr[13: 12];
+   // lower 12 bits specify addresses within the selected core.
+   wire [11: 0]         core_addr   = sys_eim_addr[11: 0];
 
 
    //----------------------------------------------------------------
@@ -73,18 +73,14 @@ module math_selector
    //----------------------------------------------------------------
    // Core Address Table
    //----------------------------------------------------------------
-   localparam   CORE_ADDR_MODEXP          = 6'd0;
-   localparam   CORE_ADDR_MODEXP_MODULUS  = 6'd1;
-   localparam   CORE_ADDR_MODEXP_EXPONENT = 6'd2;
-   localparam   CORE_ADDR_MODEXP_MESSAGE  = 6'd3;
-   localparam   CORE_ADDR_MODEXP_RESULT   = 6'd4;
+   localparam   CORE_MODEXP = 2'd0;
 
 
    //----------------------------------------------------------------
    // MODEXP
    //----------------------------------------------------------------
    `ifdef USE_CORE_MODEXP
-   wire                 enable_modexp = sys_ena && (addr_core_num >= CORE_ADDR_MODEXP) && (addr_core_num <= CORE_ADDR_MODEXP_RESULT);
+   wire                 enable_modexp = sys_ena && (core_select == CORE_MODEXP);
    wire [31: 0]         read_data_modexp;
 
    modexp modexp_inst
@@ -95,7 +91,7 @@ module math_selector
       .cs(enable_modexp & (sys_eim_rd | sys_eim_wr)),
       .we(sys_eim_wr),
 
-      .address(addr_core_reg),
+      .address(core_addr),
       .write_data(sys_write_data),
       .read_data(read_data_modexp)
       );
@@ -111,7 +107,7 @@ module math_selector
    always @*
      //
    `ifdef USE_CORE_MODEXP
-     if ((addr_core_num >= CORE_ADDR_MODEXP) && (addr_core_num <= CORE_ADDR_MODEXP_RESULT))
+     if (core_select == CORE_MODEXP)
          begin
             sys_read_data_mux = read_data_modexp;
          end