diff --git a/DA.sv b/DA.sv
index b8d1d3fdde1093515e1828a4c07fd8c5b43a9e65..52a022c88f7bb435ee48ca196206411d40ed3098 100644
--- a/DA.sv
+++ b/DA.sv
@@ -8,17 +8,18 @@
======= Signed DA MAC =======
*/
-import DA_LUT::multiplication_coefficients;
import DA_LUT::clog2;
module DA_MAC #(parameter BW = DA_LUT::BW, parameter N = DA_LUT::N)
(input logic signed [BW-1:0] in [0:N-1],
input logic input_ready, ck, rst,
+ //input logic [clog2(N)+BW:0] multiplication_coefficients [0:2**N-1],
+ input logic [(N-1)+8:0] multiplication_coefficients [0:2**N-1],
output logic signed [(2*N-1)+8:0] out,
output logic output_ready);
// ==== Local Variables ====
-logic signed [N-1:0] shifted_out;
+logic signed [BW-1:0] shifted_out;
logic signed [(N-1)+8:0] partial_sum;
typedef enum logic [1:0] {waiting, loading, processing, saving} state_type;
@@ -48,7 +49,7 @@ always_ff@(posedge ck, posedge rst)
// ==== DA accumulator ====
-always_ff @(posedge ck, posedge rst)
+always_ff @(posedge ck)
if (reset_accumulator)
begin
partial_sum <= '0;
diff --git a/DA_LUT.sv b/DA_LUT.sv
index b89de544626ef2879e2081967ad1eec60111353f..459f36870c8758c94f466032ac78769796bbd00d 100644
--- a/DA_LUT.sv
+++ b/DA_LUT.sv
@@ -3,7 +3,30 @@ package DA_LUT;
parameter N = 16;
parameter BW = 16;
-const logic signed [(BW-1)+8:0] multiplication_coefficients [0:2**N - 1] = '{
+function int clog2(input int n);
+ begin
+ clog2 = 0;
+ n--;
+ while(n > 0)
+ begin
+ clog2++;
+ n >>= 1;
+ end
+ end
+endfunction
+
+/*
+- The input to the LUT is an N Bit input vector (hence 2^N - 1 inputs)
+- The maximum value of the output would be N*(2^BW-1) assuming a BW sized coefficients and all an input vector of all 1's
+- Hence, this required log2(N*(2^BW-1))+1 (+1 for sign bit) bits to store = log2(N) + log2(2^BW-1) + 1 = (BW) + log2(N)
+
+ N | BW | log2(N) | output size
+---------------------------------------
+ 16 | 16 | 4 | 20 <----- this implementation
+ 32 | 16 | 5 | 21
+ 32 | 32 | 5 | 37s
+*/
+const logic signed [(N-1)+8:0] multiplication_coefficients [0:2**N-1] = '{
24'd0, -24'd79, -24'd136, -24'd215, 24'd312, 24'd233, 24'd176, 24'd97, 24'd654,
24'd575, 24'd518, 24'd439, 24'd966, 24'd887, 24'd830, 24'd751, -24'd1244,
-24'd1323, -24'd1380, -24'd1459, -24'd932, -24'd1011, -24'd1068, -24'd1147, -24'd590,
@@ -8195,19 +8218,6 @@ const logic signed [(BW-1)+8:0] multiplication_coefficients [0:2**N - 1] = '{
24'd33180, 24'd33123, 24'd33044, 24'd33571, 24'd33492, 24'd33435, 24'd33356, 24'd33913,
24'd33834, 24'd33777, 24'd33698, 24'd34225, 24'd34146, 24'd34089, 24'd34010, 24'd32015,
24'd31936, 24'd31879, 24'd31800, 24'd32327, 24'd32248, 24'd32191, 24'd32112, 24'd32669,
-24'd32590, 24'd32533, 24'd32454, 24'd32981, 24'd32902, 24'd32845, 24'd32766
-};
-
-function int clog2(input int n);
- begin
- clog2 = 0;
- n--;
- while(n > 0)
- begin
- clog2++;
- n >>= 1;
- end
- end
-endfunction
+24'd32590, 24'd32533, 24'd32454, 24'd32981, 24'd32902, 24'd32845, 24'd32766};
endpackage
diff --git a/DA_test.sv b/DA_test.sv
index c0f134901cde0d28537e896e8f3e989a5e6c9296..d6bfc2a957ab722a7dca1d4585a7e2ba21b3b0d2 100644
--- a/DA_test.sv
+++ b/DA_test.sv
@@ -3,14 +3,14 @@ module DA_test;
timeunit 1ns;
timeprecision 100ps;
-logic signed [15:0] in [0:15] = '{2,5,123,345,123,5,10,2342,344,22,234,543,23,65,1111,54};
+logic signed [DA_LUT::BW-1:0] in [0:DA_LUT::N-1] = '{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16};
logic input_ready, ck, rst;
-logic signed [39:0] out;
+logic signed [(2*DA_LUT::N-1)+8:0] out;
logic output_ready;
const int input_frequency = 5000;
-DA_MAC #(.BW(DA_LUT::BW), .N(DA_LUT::N)) DA (.*);
+DA_MAC #(.BW(DA_LUT::BW), .N(DA_LUT::N)) DA (.*, .multiplication_coefficients(DA_LUT::multiplication_coefficients));
// clock generator
// generates a 1 MHz clock
diff --git a/generate_LUT.cpp b/generate_LUT.cpp
index bb1fdcea71b04e91a4d838ca44d611ab74b09f62..421abbebe768c0bfc6a3e6808b6d775005617880 100644
--- a/generate_LUT.cpp
+++ b/generate_LUT.cpp
@@ -8,7 +8,8 @@
/*
- 1st arg is the propgram name
-- 2nd ... last args are the coefficients of the FIR filter
+- 2nd arg is the bit width of the coefficients
+- 3rd ... last args are the coefficients of the FIR filter
*/
int clog2(int n)
@@ -26,15 +27,16 @@ int clog2(int n)
int main(int argc, char *argv[])
{
- std::size_t num_coeff = argc - 1;
- std::size_t address_bit_width = num_coeff;
- std::size_t data_bit_width = num_coeff+8;
+ std::size_t num_coeff = argc - 2;
+ std::size_t N = num_coeff;
+ std::size_t BW = std::stoi(argv[1]);
+ std::size_t output_size = N+8;
std::vector<double> coefficients;
//generate a vector of the coefficients
for(std::size_t i = 0; i < num_coeff; ++i)
{
- coefficients.push_back(std::stod(argv[i+1]));
+ coefficients.push_back(std::stod(argv[i+2]));
}
std::ofstream dest_file;
@@ -42,7 +44,7 @@ int main(int argc, char *argv[])
//for each number in the range 0 ... pow(2,num_coeff-1), multiply each bit by the coefficients
//assuming SIGNED 2c multiplication, so num_coeff-1
- for(std::size_t i = 0; i < pow(2,num_coeff); ++i)
+ for(std::size_t i = 0; i < pow(2,N); ++i)
{
std::bitset<64> bits(i);
int sum = 0;
@@ -54,9 +56,9 @@ int main(int argc, char *argv[])
//write the value of the input, i, and the corresponding sum, sum, to a file
if(sum >= 0)
- dest_file << data_bit_width << "'d" << sum << ", ";
+ dest_file << output_size << "'d" << sum << ", ";
else
- dest_file << "-" << data_bit_width << "'d" << abs(sum) << ", ";
+ dest_file << "-" << output_size << "'d" << abs(sum) << ", ";
if(!(i%8) && i>0)
dest_file << "\n";