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fix: rewrite layer_tb and neuron_parallel_tb for current INT8 architecture

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Both testbenches instantiated their DUTs with a FRAC_BITS parameter and
Q8.8 fixed-point 16-bit values, which no longer exist in rtl/neuron_parallel.v
(now plain INT8, DATA_WIDTH=8, hardcoded +127 saturation, ReLU-only clamp).
This made both tests fail elaboration ("parameter FRAC_BITS not found").

Rewrote both benches with integer INT8 stimuli and expectations matching
the current core (no RTL changes): neuron_parallel_tb covers a mixed
vector, ReLU, positive saturation, and mixed values with a boundary
negative bias; layer_tb covers 8 neurons exercising scale, ReLU,
saturation, bias-only, and a sparse weight pattern across groups.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WQV3vS9TXaGDJ5cRfnfidt
This commit is contained in:
michele
2026-09-02 14:16:34 +02:00
co-authored by Claude Sonnet 5
parent 896f56c675
commit 4b5cd4e558
7 changed files with 17623 additions and 8338 deletions
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sim/neuron_parallel_tb.v
+38 -51
View File
@@ -2,11 +2,10 @@
module tb;
parameter DATA_WIDTH = 16;
parameter FRAC_BITS = 8;
parameter N_INPUTS = 64;
parameter DATA_WIDTH = 8;
parameter N_INPUTS = 32;
parameter PARALLEL = 8;
parameter ACC_WIDTH = 40;
parameter ACC_WIDTH = 32;
reg clk;
reg rst;
@@ -25,7 +24,6 @@ module tb;
neuron_parallel #(
.DATA_WIDTH(DATA_WIDTH),
.FRAC_BITS(FRAC_BITS),
.N_INPUTS(N_INPUTS),
.PARALLEL(PARALLEL),
.ACC_WIDTH(ACC_WIDTH)
@@ -47,16 +45,6 @@ module tb;
forever #5 clk = ~clk;
end
// ------------------------------------------------------------
// Helper: convert real value to Q8.8
// ------------------------------------------------------------
function signed [15:0] q8_8;
input real value;
begin
q8_8 = $rtoi(value * 256.0);
end
endfunction
// ------------------------------------------------------------
// Start neuron and wait for completion
// ------------------------------------------------------------
@@ -79,14 +67,13 @@ module tb;
//
// Diverse vector:
//
// x0 = 1.5 w0 = 2.0 -> 3.0
// x1 = 2.0 w1 = -1.0 -> -2.0
// x2 = 0.5 w2 = 0.25 -> 0.125
// x0 = 3 w0 = 2 -> 6
// x1 = 4 w1 = -1 -> -4
// x2 = 2 w2 = 1 -> 2
//
// bias = 0.609375
// bias = 1
//
// total = 1.734375
// Q8.8 = 444
// total = 6 - 4 + 2 + 1 = 5
// ------------------------------------------------------------
task test_1;
begin
@@ -95,23 +82,23 @@ module tb;
x_bus = 0;
w_bus = 0;
bias = q8_8(0.609375);
bias = 8'sd1;
x_bus[0*16 +: 16] = q8_8(1.5);
w_bus[0*16 +: 16] = q8_8(2.0);
x_bus[0*DATA_WIDTH +: DATA_WIDTH] = 8'sd3;
w_bus[0*DATA_WIDTH +: DATA_WIDTH] = 8'sd2;
x_bus[1*16 +: 16] = q8_8(2.0);
w_bus[1*16 +: 16] = q8_8(-1.0);
x_bus[1*DATA_WIDTH +: DATA_WIDTH] = 8'sd4;
w_bus[1*DATA_WIDTH +: DATA_WIDTH] = -8'sd1;
x_bus[2*16 +: 16] = q8_8(0.5);
w_bus[2*16 +: 16] = q8_8(0.25);
x_bus[2*DATA_WIDTH +: DATA_WIDTH] = 8'sd2;
w_bus[2*DATA_WIDTH +: DATA_WIDTH] = 8'sd1;
run_neuron;
$display("RTL = %0d", y);
$display("EXPECTED = 444");
$display("EXPECTED = 5");
if (y !== 16'sd444) begin
if (y !== 8'sd5) begin
$display("FAIL - TEST 1");
errors = errors + 1;
end
@@ -137,8 +124,8 @@ module tb;
bias = 0;
for (i = 0; i < N_INPUTS; i = i + 1) begin
x_bus[i*16 +: 16] = q8_8(1.0);
w_bus[i*16 +: 16] = q8_8(-1.0);
x_bus[i*DATA_WIDTH +: DATA_WIDTH] = 8'sd1;
w_bus[i*DATA_WIDTH +: DATA_WIDTH] = -8'sd1;
end
run_neuron;
@@ -146,7 +133,7 @@ module tb;
$display("RTL = %0d", y);
$display("EXPECTED = 0");
if (y !== 16'sd0) begin
if (y !== 8'sd0) begin
$display("FAIL - TEST 2");
errors = errors + 1;
end
@@ -160,7 +147,7 @@ module tb;
// TEST 3
//
// Large positive result.
// Must saturate to +32767.
// Must saturate to +127 (INT8).
// ------------------------------------------------------------
task test_3;
begin
@@ -172,16 +159,16 @@ module tb;
bias = 0;
for (i = 0; i < N_INPUTS; i = i + 1) begin
x_bus[i*16 +: 16] = q8_8(127.0);
w_bus[i*16 +: 16] = q8_8(2.0);
x_bus[i*DATA_WIDTH +: DATA_WIDTH] = 8'sd100;
w_bus[i*DATA_WIDTH +: DATA_WIDTH] = 8'sd2;
end
run_neuron;
$display("RTL = %0d", y);
$display("EXPECTED = 32767");
$display("EXPECTED = 127");
if (y !== 16'sd32767) begin
if (y !== 8'sd127) begin
$display("FAIL - TEST 3");
errors = errors + 1;
end
@@ -196,12 +183,12 @@ module tb;
//
// Mixed positive/negative products.
//
// 32 x (+1)
// 32 x (-1)
// sum = 0
// bias = -1
// 16 x (2 * 1) = 32
// 16 x (-1 * 1) = -16
// sum = 16
// bias = -16
//
// ReLU -> 0
// total = 0 -> ReLU boundary -> 0
// ------------------------------------------------------------
task test_4;
begin
@@ -210,16 +197,16 @@ module tb;
x_bus = 0;
w_bus = 0;
bias = q8_8(-1.0);
bias = -8'sd16;
for (i = 0; i < N_INPUTS; i = i + 1) begin
if ((i % 2) == 0) begin
x_bus[i*16 +: 16] = q8_8(2.0);
w_bus[i*16 +: 16] = q8_8(0.5);
x_bus[i*DATA_WIDTH +: DATA_WIDTH] = 8'sd2;
w_bus[i*DATA_WIDTH +: DATA_WIDTH] = 8'sd1;
end
else begin
x_bus[i*16 +: 16] = q8_8(-1.0);
w_bus[i*16 +: 16] = q8_8(1.0);
x_bus[i*DATA_WIDTH +: DATA_WIDTH] = -8'sd1;
w_bus[i*DATA_WIDTH +: DATA_WIDTH] = 8'sd1;
end
end
@@ -228,7 +215,7 @@ module tb;
$display("RTL = %0d", y);
$display("EXPECTED = 0");
if (y !== 16'sd0) begin
if (y !== 8'sd0) begin
$display("FAIL - TEST 4");
errors = errors + 1;
end
@@ -259,7 +246,7 @@ module tb;
$display("");
$display("==============================");
$display("NEURON_PARALLEL TESTBENCH");
$display("NEURON_PARALLEL TESTBENCH (INT8)");
$display("==============================");
test_1;
@@ -283,4 +270,4 @@ module tb;
$finish;
end
endmodule
endmodule