From bccd638d2b1f27a464d090db8a81cc1e6ca08ddf Mon Sep 17 00:00:00 2001
From: yannickreiss <yannick.reiss@protonmail.ch>
Date: Tue, 26 Sep 2023 11:37:27 +0200
Subject: [PATCH] Implement brainfuck ptr

---
 fpga/src/memoryPointer.vhd | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/fpga/src/memoryPointer.vhd b/fpga/src/memoryPointer.vhd
index e69de29..141395b 100644
--- a/fpga/src/memoryPointer.vhd
+++ b/fpga/src/memoryPointer.vhd
@@ -0,0 +1,35 @@
+-- memoryPointer.vhd
+-- Created on: Di 26. Sep 11:11:49 CEST 2023
+-- Author(s): Yannick Reiß
+-- Content: Store current ptr. Part of brainfuck logic
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+-- Entity ptr: 15 bit pointer to cell
+entity ptr is
+    port(
+        clk	        :	in	std_logic;
+		enable_ptr	:	in	std_logic;
+		new_ptr	    :	in	std_logic_vector(15 downto 0);
+
+		old_ptr	    :	out	std_logic_vector(15 downto 0)
+    );
+end ptr;
+
+-- Architecture implement_ptr of ptr:
+architecture implement_ptr of ptr is
+    signal reg : std_logic_vector(15 downto 0);
+begin
+
+    -- Process Write  set new_ptr
+    write : process (clk) -- runs only, when clk changed
+    begin
+        if rising_edge(clk) and enable_ptr = '1' then
+            reg <= new_ptr;
+        end if;
+    end process;
+
+    old_ptr <= reg;
+
+end implement_ptr;