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authorJoachim StroĢˆmbergson <joachim@secworks.se>2015-04-27 11:17:08 +0200
committerJoachim StroĢˆmbergson <joachim@secworks.se>2015-04-27 11:17:08 +0200
commita315223f98fa6f1fdea2b1080c5f3e33352ebb13 (patch)
tree0fb3f6c458df78f58017e9475ff3b0c5cb3b52d0 /src/rtl
parent502f0f429a261628fe5e43582280012541c40804 (diff)
Updating modexp core to v 0.50. This version contains a working core that can perform sign and verify with big keys/values. The core builds ok in Altera and Xilinx FPGA tools. This commit also includes a new testgenerator capable of generating testbench for modexp with autgenerated test data of different lengths. The README has been updated with status and implementation results in for different FPGA devices.
Diffstat (limited to 'src/rtl')
-rw-r--r--src/rtl/modexp.v348
-rw-r--r--src/rtl/montprod.v12
2 files changed, 261 insertions, 99 deletions
diff --git a/src/rtl/modexp.v b/src/rtl/modexp.v
index d64a556..9f3d4f0 100644
--- a/src/rtl/modexp.v
+++ b/src/rtl/modexp.v
@@ -71,35 +71,38 @@ module modexp(
localparam ADDR_NAME0 = 8'h00;
localparam ADDR_NAME1 = 8'h01;
localparam ADDR_VERSION = 8'h02;
- localparam ADDR_CTRL = 8'h03;
+ localparam ADDR_CTRL = 8'h08;
localparam CTRL_INIT_BIT = 0;
localparam CTRL_NEXT_BIT = 1;
localparam ADDR_STATUS = 8'h09;
+ localparam STATUS_READY_BIT = 0;
+
+ localparam ADDR_MODULUS_LENGTH = 8'h20;
+ localparam ADDR_EXPONENT_LENGTH = 8'h21;
+ localparam ADDR_LENGTH = 8'h22; // Should be deprecated.
- localparam ADDR_MODSIZE = 8'h20;
- localparam ADDR_LENGTH = 8'h21;
- localparam ADDR_EXPONENT = 8'h22;
localparam MODULUS_PREFIX = 4'h1;
localparam ADDR_MODULUS_START = 8'h00;
localparam ADDR_MODULUS_END = 8'hff;
+
localparam EXPONENT_PREFIX = 4'h2;
localparam ADDR_EXPONENT_START = 8'h00;
localparam ADDR_EXPONENT_END = 8'hff;
+
localparam MESSAGE_PREFIX = 4'h3;
localparam MESSAGE_START = 8'h00;
localparam MESSAGE_END = 8'hff;
+
localparam RESULT_PREFIX = 4'h4;
localparam RESULT_START = 8'h00;
localparam RESULT_END = 8'hff;
- localparam LENGTH_PREFIX = 4'h5;
-
localparam DEFAULT_MODLENGTH = 8'h80;
localparam DEFAULT_EXPLENGTH = 8'h80;
@@ -107,7 +110,7 @@ module modexp(
localparam MONTPROD_SELECT_X_NR = 3'h1;
localparam MONTPROD_SELECT_Z_P = 3'h2;
localparam MONTPROD_SELECT_P_P = 3'h3;
- localparam MONTPROD_SELECT_ONE_Z = 3'h4;
+ localparam MONTPROD_SELECT_Z_ONE = 3'h4;
localparam MONTPROD_DEST_Z = 2'b00;
localparam MONTPROD_DEST_P = 2'b01;
@@ -124,53 +127,36 @@ module modexp(
localparam CTRL_CALCULATE_ZN = 4'h8;
localparam CTRL_DONE = 4'h9;
+ localparam EXPONATION_MODE_SECRET_SECURE = 1'b0;
+ localparam EXPONATION_MODE_PUBLIC_FAST = 1'b1; //for rsa, c=M^65537 etc, there is no need to slow down to hide the exponent
+
+
localparam CORE_NAME0 = 32'h6d6f6465; // "mode"
localparam CORE_NAME1 = 32'h78702020; // "xp "
- localparam CORE_VERSION = 32'h302e3031; // "0.01"
+ localparam CORE_VERSION = 32'h302e3530; // "0.50"
//----------------------------------------------------------------
// Registers including update variables and write enable.
//----------------------------------------------------------------
- reg [07 : 0] modulus_mem_int_rd_addr;
- wire [31 : 0] modulus_mem_int_rd_data;
- wire [31 : 0] modulus_mem_api_rd_data;
- reg modulus_mem_api_we;
-
- reg [07 : 0] message_mem_int_rd_addr;
- wire [31 : 0] message_mem_int_rd_data;
- wire [31 : 0] message_mem_api_rd_data;
- reg message_mem_api_we;
-
- reg [07 : 0] exponent_mem_int_rd_addr;
- wire [31 : 0] exponent_mem_int_rd_data;
- wire [31 : 0] exponent_mem_api_rd_data;
- reg exponent_mem_api_we;
+ reg [07 : 0] exponent_length_reg;
+ reg [07 : 0] exponent_length_new;
+ reg exponent_length_we;
- wire [31 : 0] result_mem_api_rd_data;
- reg [07 : 0] result_mem_int_rd_addr;
- wire [31 : 0] result_mem_int_rd_data;
- reg [07 : 0] result_mem_int_wr_addr;
- reg [31 : 0] result_mem_int_wr_data;
- reg result_mem_int_we;
-
- reg [07 : 0] p_mem_rd0_addr;
- wire [31 : 0] p_mem_rd0_data;
- reg [07 : 0] p_mem_rd1_addr;
- wire [31 : 0] p_mem_rd1_data;
- reg [07 : 0] p_mem_wr_addr;
- reg [31 : 0] p_mem_wr_data;
- reg p_mem_we;
+ reg [07 : 0] modulus_length_reg;
+ reg [07 : 0] modulus_length_new;
+ reg modulus_length_we;
reg [07 : 0] length_reg;
+ reg [07 : 0] length_new;
reg [07 : 0] length_m1_reg;
- reg [07 : 0] length_new; //TODO: API should write length!!!
- reg [07 : 0] length_m1_new; //TODO: API should write length-1 when writing length!!!
- reg length_we; //TODO: API should enable length_we!!!
+ reg [07 : 0] length_m1_new;
+ reg length_we;
reg start_reg;
- reg start_new; //TODO: API should start operations!!!
- reg start_we; //TODO: API should start operations!!!
+ reg start_new;
+ reg start_we;
+ reg clear_start;
reg ready_reg;
reg ready_new;
@@ -187,22 +173,61 @@ module modexp(
reg [3 : 0] modexp_ctrl_new;
reg modexp_ctrl_we;
- reg [31 : 0] one;
+ reg [31 : 0] one_reg;
reg [31 : 0] one_new;
+ reg [31 : 0] b_one_reg;
+ reg [31 : 0] b_one_new;
reg [12 : 0] loop_counter_reg;
reg [12 : 0] loop_counter_new;
reg loop_counter_we;
+
reg [07 : 0] E_word_index;
reg [04 : 0] E_bit_index;
reg last_iteration;
+
reg ei_reg;
reg ei_new;
reg ei_we;
+ reg exponation_mode_reg;
+ reg exponation_mode_new;
+ reg exponation_mode_we;
+
+
//----------------------------------------------------------------
// Wires.
//----------------------------------------------------------------
+ reg [07 : 0] modulus_mem_int_rd_addr;
+ wire [31 : 0] modulus_mem_int_rd_data;
+ wire [31 : 0] modulus_mem_api_rd_data;
+ reg modulus_mem_api_we;
+
+ reg [07 : 0] message_mem_int_rd_addr;
+ wire [31 : 0] message_mem_int_rd_data;
+ wire [31 : 0] message_mem_api_rd_data;
+ reg message_mem_api_we;
+
+ reg [07 : 0] exponent_mem_int_rd_addr;
+ wire [31 : 0] exponent_mem_int_rd_data;
+ wire [31 : 0] exponent_mem_api_rd_data;
+ reg exponent_mem_api_we;
+
+ wire [31 : 0] result_mem_api_rd_data;
+ reg [07 : 0] result_mem_int_rd_addr;
+ wire [31 : 0] result_mem_int_rd_data;
+ reg [07 : 0] result_mem_int_wr_addr;
+ reg [31 : 0] result_mem_int_wr_data;
+ reg result_mem_int_we;
+
+ reg [07 : 0] p_mem_rd0_addr;
+ wire [31 : 0] p_mem_rd0_data;
+ reg [07 : 0] p_mem_rd1_addr;
+ wire [31 : 0] p_mem_rd1_data;
+ reg [07 : 0] p_mem_wr_addr;
+ reg [31 : 0] p_mem_wr_data;
+ reg p_mem_we;
+
reg [31 : 0] tmp_read_data;
//reg tmp_error;
@@ -225,7 +250,7 @@ module modexp(
reg residue_calculate;
wire residue_ready;
- reg [14 : 0] residue_nn;
+ reg [14 : 0] residue_nn;
reg [07 : 0] residue_length;
wire [07 : 0] residue_opa_rd_addr;
wire [31 : 0] residue_opa_rd_data;
@@ -238,6 +263,11 @@ module modexp(
reg [07 : 0] residue_mem_montprod_read_addr;
wire [31 : 0] residue_mem_montprod_read_data;
+ reg residue_valid_reg;
+ reg residue_valid_new;
+ reg invalidate_residue;
+ reg residue_valid_int_validated;
+
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
@@ -368,18 +398,37 @@ module modexp(
begin
if (!reset_n)
begin
+ exponent_length_reg <= DEFAULT_EXPLENGTH;
+ modulus_length_reg <= DEFAULT_MODLENGTH;
+ start_reg <= 1'b0;
ready_reg <= 1'b1;
montprod_select_reg <= MONTPROD_SELECT_ONE_NR;
montprod_dest_reg <= MONTPROD_DEST_NOWHERE;
modexp_ctrl_reg <= CTRL_IDLE;
- one <= 32'h0;
+ one_reg <= 32'h0;
+ b_one_reg <= 32'h0;
length_reg <= 8'h0;
length_m1_reg <= 8'h0;
loop_counter_reg <= 13'b0;
ei_reg <= 1'b0;
+ residue_valid_reg <= 1'b0;
+ exponation_mode_reg <= EXPONATION_MODE_SECRET_SECURE;
end
else
begin
+ one_reg <= one_new;
+ b_one_reg <= b_one_new;
+ residue_valid_reg <= residue_valid_new;
+
+ if (exponent_length_we)
+ exponent_length_reg <= exponent_length_new;
+
+ if (modulus_length_we)
+ modulus_length_reg <= modulus_length_new;
+
+ if (start_we)
+ start_reg <= start_new;
+
if (ready_we)
ready_reg <= ready_new;
@@ -394,8 +443,8 @@ module modexp(
if (length_we)
begin
- length_reg <= write_data[7 : 0];
- length_m1_reg <= write_data[7 : 0] - 8'h1;
+ length_reg <= length_new;
+ length_m1_reg <= length_m1_new;
end
if (loop_counter_we)
@@ -404,7 +453,8 @@ module modexp(
if (ei_we)
ei_reg <= ei_new;
- one <= one_new;
+ if (exponation_mode_we)
+ exponation_mode_reg <= exponation_mode_new;
end
end // reg_update
@@ -416,12 +466,35 @@ module modexp(
//----------------------------------------------------------------
always @*
begin : api
+ modulus_length_we = 1'b0;
+ exponent_length_we = 1'b0;
+ start_new = 1'b0;
+ start_we = 1'b0;
modulus_mem_api_we = 1'b0;
exponent_mem_api_we = 1'b0;
message_mem_api_we = 1'b0;
length_we = 1'b0;
+ invalidate_residue = 1'b0;
+
+ //TODO: Add API code to enable fast exponation for working with public exponents.
+ exponation_mode_we = 1'b0;
+
+ exponation_mode_new = EXPONATION_MODE_SECRET_SECURE;
+ modulus_length_new = write_data[7 : 0];
+ exponent_length_new = write_data[7 : 0];
+ length_new = write_data[7 : 0];
+ length_m1_new = write_data[7 : 0] - 8'h1;
+
tmp_read_data = 32'h00000000;
+ // We need to be able to clear start bit after we have
+ // started a modexp operation.
+ if (clear_start)
+ begin
+ start_new = 1'b0;
+ start_we = 1'b1;
+ end
+
if (cs)
begin
case (address[11 : 8])
@@ -430,8 +503,26 @@ module modexp(
if (we)
begin
case (address[7 : 0])
+ ADDR_CTRL:
+ begin
+ start_new = write_data[0];
+ start_we = 1'b1;
+ end
+
ADDR_LENGTH:
- length_we = 1'b1;
+ begin
+ length_we = 1'b1;
+ end
+
+ ADDR_MODULUS_LENGTH:
+ begin
+ modulus_length_we = 1'b1;
+ end
+
+ ADDR_EXPONENT_LENGTH:
+ begin
+ exponent_length_we = 1'b1;
+ end
default:
begin
@@ -451,10 +542,16 @@ module modexp(
tmp_read_data = CORE_VERSION;
ADDR_CTRL:
- tmp_read_data = 32'h00000000;
+ tmp_read_data = {31'h00000000, start_reg};
ADDR_STATUS:
- tmp_read_data = 32'h00000000;
+ tmp_read_data = {31'h00000000, ready_reg};
+
+ ADDR_MODULUS_LENGTH:
+ tmp_read_data = {24'h000000, modulus_length_reg};
+
+ ADDR_EXPONENT_LENGTH:
+ tmp_read_data = {24'h000000, exponent_length_reg};
ADDR_LENGTH:
tmp_read_data = {24'h000000, length_reg};
@@ -471,6 +568,7 @@ module modexp(
if (we)
begin
modulus_mem_api_we = 1'b1;
+ invalidate_residue = 1'b1;
end
else
begin
@@ -522,15 +620,19 @@ module modexp(
// generates the big integer one ( 00... 01 )
//----------------------------------------------------------------
always @*
- begin : one_process;
+ begin : one_process
+ one_new = 32'h00000000;
+ b_one_new = 32'h00000000;
if (montprod_opa_addr == length_m1_reg)
one_new = 32'h00000001;
- else
- one_new = 32'h00000000;
+ if (montprod_opb_addr == length_m1_reg)
+ b_one_new = 32'h00000001;
end
+
//----------------------------------------------------------------
- // read mux for modulus, since it is being addressed by two sources
+ // Read mux for modulus. Needed since it is being
+ // addressed by two sources.
//----------------------------------------------------------------
always @*
begin : modulus_mem_reader_process
@@ -540,21 +642,38 @@ module modexp(
modulus_mem_int_rd_addr = montprod_opm_addr;
end
+
//----------------------------------------------------------------
- // feeds residue calculator
+ // Feeds residue calculator.
//----------------------------------------------------------------
always @*
- begin : residue_process;
- residue_nn = { 1'b0, length_reg, 6'h0 }; //N*2, N=length*32, *32 = shl5, *64 = shl6
+ begin : residue_process
+ //N*2, N=length*32, *32 = shl5, *64 = shl6
+ residue_nn = { 1'b0, length_reg, 6'h0 };
residue_length = length_reg;
residue_opm_data = modulus_mem_int_rd_data;
end
+
+ //----------------------------------------------------------------
+ // Sets the register that decides if residue is valid or not.
+ //----------------------------------------------------------------
+ always @*
+ begin : residue_valid_process
+ if (invalidate_residue)
+ residue_valid_new = 1'b0;
+ else if ( residue_valid_int_validated == 1'b1)
+ residue_valid_new = 1'b1;
+ else
+ residue_valid_new = residue_valid_reg;
+ end
+
+
//----------------------------------------------------------------
// montprod_op_select
//
// Select operands used during montprod calculations depending
- // on what operation we want to do
+ // on what operation we want to do.
//----------------------------------------------------------------
always @*
begin : montprod_op_select
@@ -572,7 +691,7 @@ module modexp(
case (montprod_select_reg)
MONTPROD_SELECT_ONE_NR:
begin
- montprod_opa_data = one;
+ montprod_opa_data = one_reg;
montprod_opb_data = residue_mem_montprod_read_data;
end
@@ -594,10 +713,10 @@ module modexp(
montprod_opb_data = p_mem_rd1_data;
end
- MONTPROD_SELECT_ONE_Z:
+ MONTPROD_SELECT_Z_ONE:
begin
- montprod_opa_data = one;
- montprod_opb_data = result_mem_int_rd_data;
+ montprod_opa_data = result_mem_int_rd_data;
+ montprod_opb_data = b_one_reg;
end
default:
@@ -612,7 +731,7 @@ module modexp(
//----------------------------------------------------------------
// memory write mux
//
- // direct memory write signals to correct memory
+ // Direct memory write signals to correct memory.
//----------------------------------------------------------------
always @*
begin : memory_write_process
@@ -643,11 +762,12 @@ module modexp(
//----------------------------------------------------------------
// loop_counter
//
- // Calculate the loop counter and related variables
+ // Calculate the loop counter and related variables.
//----------------------------------------------------------------
always @*
begin : loop_counters_process
- E_bit_index = loop_counter_reg[ 04 : 0 ];
+ loop_counter_new = 13'b0;
+ loop_counter_we = 1'b0;
if (loop_counter_reg == { length_m1_reg, 5'b11111 })
last_iteration = 1'b1;
@@ -669,7 +789,7 @@ module modexp(
default:
begin
- loop_counter_new = 13'b0;
+ loop_counter_new = loop_counter_reg;
loop_counter_we = 1'b0;
end
@@ -680,12 +800,15 @@ module modexp(
//----------------------------------------------------------------
// exponent
//
- // reads the exponent
+ // Reads the exponent.
//----------------------------------------------------------------
always @*
begin : exponent_process
- // accessing new instead of reg - pick up update at CTRL_ITERATE_NEW to remove a pipeline stall
- E_word_index = loop_counter_new[ 12 : 5 ];
+ // Accessing new instead of reg - pick up update at
+ // CTRL_ITERATE_NEW to remove a pipeline stall.
+ E_word_index = length_m1_reg - loop_counter_new[ 12 : 5 ];
+
+ E_bit_index = loop_counter_reg[ 04 : 0 ];
exponent_mem_int_rd_addr = E_word_index;
@@ -705,48 +828,70 @@ module modexp(
//----------------------------------------------------------------
always @*
begin
- ready_new = 0;
- ready_we = 0;
+ ready_new = 1'b0;
+ ready_we = 1'b0;
montprod_select_new = MONTPROD_SELECT_ONE_NR;
montprod_select_we = 0;
montprod_dest_new = MONTPROD_DEST_NOWHERE;
montprod_dest_we = 0;
montprod_calc = 0;
modexp_ctrl_new = CTRL_IDLE;
- modexp_ctrl_we = 0;
+ modexp_ctrl_we = 1'b0;
+ clear_start = 1'b0;
residue_calculate = 1'b0;
+ residue_valid_int_validated = 1'b0;
+
case (modexp_ctrl_reg)
CTRL_IDLE:
begin
- ready_new = 0;
- ready_we = 1;
- if (start_reg == 1'b1)
+ if (start_reg)
begin
- modexp_ctrl_new = CTRL_RESIDUE;
- modexp_ctrl_we = 1;
- residue_calculate = 1'b1;
+ ready_new = 1'b0;
+ ready_we = 1'b1;
+ modexp_ctrl_new = CTRL_DONE;
+ modexp_ctrl_we = 1'b1;
+
+ if (residue_valid_reg)
+ begin
+ //residue has alrady been calculated, start with MONTPROD( 1, Nr, MODULUS )
+ montprod_select_new = MONTPROD_SELECT_ONE_NR;
+ montprod_select_we = 1;
+ montprod_dest_new = MONTPROD_DEST_Z;
+ montprod_dest_we = 1;
+ montprod_calc = 1;
+ modexp_ctrl_new = CTRL_CALCULATE_Z0;
+ modexp_ctrl_we = 1;
+ end
+ else
+ begin
+ //modulus has been written and residue (Nr) must be calculated
+ modexp_ctrl_new = CTRL_RESIDUE;
+ modexp_ctrl_we = 1;
+ residue_calculate = 1'b1;
+ end
end
end
CTRL_RESIDUE:
begin
- if (residue_ready == 1'b1)
+ if (residue_ready)
begin
montprod_select_new = MONTPROD_SELECT_ONE_NR;
montprod_select_we = 1;
montprod_dest_new = MONTPROD_DEST_Z;
montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_CALCULATE_Z0;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_CALCULATE_Z0;
+ modexp_ctrl_we = 1;
+ residue_valid_int_validated = 1'b1; //update registers telling residue is valid
end
end
CTRL_CALCULATE_Z0:
begin
- if (montprod_ready == 1'b1)
+ if (montprod_ready)
begin
montprod_select_new = MONTPROD_SELECT_X_NR;
montprod_select_we = 1;
@@ -774,20 +919,28 @@ module modexp(
montprod_dest_new = MONTPROD_DEST_Z;
montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_ITERATE_Z_P;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_ITERATE_Z_P;
+ modexp_ctrl_we = 1;
+
+ if (ei_new == 1'b0 && exponation_mode_reg == EXPONATION_MODE_PUBLIC_FAST)
+ begin
+ //Skip the fake montgomery calculation, exponation_mode_reg optimizing for speed not blinding.
+ montprod_select_new = MONTPROD_SELECT_P_P;
+ montprod_dest_new = MONTPROD_DEST_P;
+ modexp_ctrl_new = CTRL_ITERATE_P_P;
+ end
end
CTRL_ITERATE_Z_P:
- if (montprod_ready == 1'b1)
+ if (montprod_ready)
begin
montprod_select_new = MONTPROD_SELECT_P_P;
montprod_select_we = 1;
montprod_dest_new = MONTPROD_DEST_P;
montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_ITERATE_P_P;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_ITERATE_P_P;
+ modexp_ctrl_we = 1;
end
CTRL_ITERATE_P_P:
@@ -799,24 +952,26 @@ module modexp(
CTRL_ITERATE_END:
begin
- if (last_iteration == 1'b0)
+ if (!last_iteration)
begin
modexp_ctrl_new = CTRL_ITERATE;
modexp_ctrl_we = 1;
end
else
begin
- montprod_select_new = MONTPROD_SELECT_ONE_Z;
+ montprod_select_new = MONTPROD_SELECT_Z_ONE;
montprod_select_we = 1;
+ montprod_dest_new = MONTPROD_DEST_Z;
+ montprod_dest_we = 1;
montprod_calc = 1;
- modexp_ctrl_new = CTRL_CALCULATE_ZN;
- modexp_ctrl_we = 1;
+ modexp_ctrl_new = CTRL_CALCULATE_ZN;
+ modexp_ctrl_we = 1;
end
end
CTRL_CALCULATE_ZN:
begin
- if (montprod_ready == 1'b1)
+ if (montprod_ready)
begin
modexp_ctrl_new = CTRL_DONE;
modexp_ctrl_we = 1;
@@ -825,10 +980,11 @@ module modexp(
CTRL_DONE:
begin
- ready_new = 1;
- ready_we = 1;
- modexp_ctrl_new = CTRL_IDLE;
- modexp_ctrl_we = 1;
+ clear_start = 1'b1;
+ ready_new = 1'b1;
+ ready_we = 1'b1;
+ modexp_ctrl_new = CTRL_IDLE;
+ modexp_ctrl_we = 1;
end
default:
diff --git a/src/rtl/montprod.v b/src/rtl/montprod.v
index 32bbdec..2ed1f5d 100644
--- a/src/rtl/montprod.v
+++ b/src/rtl/montprod.v
@@ -63,6 +63,7 @@ module montprod(
//----------------------------------------------------------------
// Internal constant and parameter definitions.
//----------------------------------------------------------------
+
localparam CTRL_IDLE = 4'h0;
localparam CTRL_INIT_S = 4'h1;
localparam CTRL_LOOP_INIT = 4'h2;
@@ -217,9 +218,11 @@ module montprod(
SMUX_SHR:
s_mem_new = shr_adiv2;
endcase
- $display("SMUX%x: %x", s_mux_reg, s_mem_new);
+ if (DEBUG)
+ $display("SMUX%x: %x", s_mux_reg, s_mem_new);
end
+
//----------------------------------------------------------------
// reg_update
//
@@ -286,7 +289,8 @@ module montprod(
//opa_addr will point to length-1 to get A LSB.
//s_read_addr will point to length-1
q = s_mem_read_data[0] ^ (opa_data[0] & b);
- $display("s_mem_read_data: %x opa_data %x b %x q %x B_bit_index_reg %x", s_mem_read_data, opa_data, b, q, B_bit_index_reg);
+ if (DEBUG)
+ $display("s_mem_read_data: %x opa_data %x b %x q %x B_bit_index_reg %x", s_mem_read_data, opa_data, b, q, B_bit_index_reg);
end
end
@@ -296,6 +300,7 @@ module montprod(
//----------------------------------------------------------------
always @*
begin : loop_counter_process
+ loop_counter_new = loop_counter;
length_m1 = length - 1'b1;
loop_counter_dec = loop_counter - 1'b1;
B_word_index = loop_counter[12:5];
@@ -560,7 +565,8 @@ module montprod(
CTRL_EMIT_S:
begin
- $display("EMIT_S word_index: %d", word_index);
+ if (DEBUG)
+ $display("EMIT_S word_index: %d", word_index);
if (word_index_prev == 8'h0)
begin
montprod_ctrl_new = CTRL_DONE;