From 5d95607192380be5cc62592efac52814a0e090df Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Tue, 23 Mar 2021 12:22:38 -0700
Subject: Initial commit.

---
 ntoa.sv | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 ntoa.sv

(limited to 'ntoa.sv')

diff --git a/ntoa.sv b/ntoa.sv
new file mode 100644
index 0000000..c55c9e6
--- /dev/null
+++ b/ntoa.sv
@@ -0,0 +1,83 @@
+module ntoa
+    #(  BITS = 8
+    )
+    (   input   bit clk
+    ,   input   bit reset
+
+    ,   output  bit             n_ready
+    ,   input   bit             n_valid `define n_valid $past(n_valid)
+    ,   input   bit [BITS-1:0]  n_data  `define n_data $past(n_data)
+
+    ,   input   bit         a_ready `define a_ready $past(a_ready)
+    ,   output  bit         a_valid
+    ,   output  bit [7:0]   a_data
+    );
+
+bit bcd_ready;
+bit bcd_valid;
+bit [b2b.DIGITS-1:0][b2b.BASE_BITS-1:0] bcd_data;
+
+bin2bcd
+    #(  .BITS(BITS)
+    ,   .BASE(10)
+    ) b2b
+    (   .clk(clk)
+    ,   .reset(reset)
+
+    ,   .bin_ready(n_ready)
+    ,   .bin_valid(n_valid)
+    ,   .bin_data(n_data)
+
+    ,   .bcd_ready(bcd_ready)
+    ,   .bcd_valid(bcd_valid)   `define bcd_valid $past(bcd_valid)
+    ,   .bcd_data(bcd_data)     `define bcd_data $past(bcd_data)
+    );
+
+bit bcd_b_valid;
+bit [b2b.DIGITS-1:0][b2b.BASE_BITS-1:0] bcd_b_data;
+
+bit [$clog2(b2b.DIGITS):0] work;
+
+always_ff @(posedge clk) begin
+    if (reset) begin
+        a_valid = 0;
+        bcd_ready = 0;
+        bcd_b_valid = 0;
+    end else begin
+        if (bcd_ready && `bcd_valid) begin
+            bcd_b_valid = 1;
+            bcd_b_data = `bcd_data;
+            // verilator lint_off WIDTH
+            work = b2b.DIGITS;
+            // verilator lint_on WIDTH
+            for (int i = b2b.DIGITS; i > 1; i = i - 1) begin
+                if (bcd_b_data[b2b.DIGITS-1] != 0) break;
+                bcd_b_data = { bcd_b_data[b2b.DIGITS-2:0], {b2b.BASE_BITS{1'b0}} };
+                work = work - 1;
+            end
+        end
+
+        if (`a_ready) a_valid = 0;
+        if (!a_valid && bcd_b_valid) begin
+            if (work != 0) begin
+                a_valid = 1;
+                // verilator lint_off WIDTH
+                if (bcd_b_data[b2b.DIGITS-1] < 10)
+                    a_data = "0" + bcd_b_data[b2b.DIGITS-1];
+                else
+                    a_data = "a" + bcd_b_data[b2b.DIGITS-1] - 10;
+                // verilator lint_off WIDTH
+                bcd_b_data = { bcd_b_data[b2b.DIGITS-2:0], {b2b.BASE_BITS{1'b0}} };
+                work = work - 1;
+            end else begin
+                a_valid = 1;
+                a_data = ",";
+                bcd_b_valid = 0;
+            end
+        end
+
+        bcd_ready = !bcd_b_valid;
+    end
+end
+
+endmodule
-- 
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