From d658cd0ae5f7de9f716b8571a3011ff1369244f7 Mon Sep 17 00:00:00 2001
From: Maik Merten <maikmerten@googlemail.com>
Date: Sat, 9 Aug 2014 14:57:18 +0200
Subject: [PATCH] completely untested and incomplete implementation of the SD
 card interface of the MULTICOMP

---
 .../loomcom/symon/devices/SdController.java   | 171 ++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 src/main/java/com/loomcom/symon/devices/SdController.java

diff --git a/src/main/java/com/loomcom/symon/devices/SdController.java b/src/main/java/com/loomcom/symon/devices/SdController.java
new file mode 100644
index 0000000..e637b16
--- /dev/null
+++ b/src/main/java/com/loomcom/symon/devices/SdController.java
@@ -0,0 +1,171 @@
+/*
+ * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ *                         Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+package com.loomcom.symon.devices;
+
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Emulation for the SD-card controller of the MULTICOMP system.
+ * Neiter comlete nor correct.
+ * 
+ */
+public class SdController extends Device {
+    
+    private enum Status {
+        IDLE,
+        READ,
+        WRITE
+    }
+    
+    public static final int CONTROLLER_SIZE = 8;
+    private final static Logger logger = Logger.getLogger(SdController.class.getName());
+    private byte[] sdcontent;
+    
+    private int lba0,lba1,lba2;
+    private int command;
+    private int position;
+    private Status status;
+   
+    
+    public SdController(int address) throws MemoryRangeException {
+        super(address, address + CONTROLLER_SIZE - 1, "SDCONTROLLER");
+        
+        // assume an empty 64K SD card by default
+        sdcontent = new byte[64 * 1024];
+        
+        // try to load an actual SD card image
+        try {
+            FileInputStream fis = new FileInputStream(new File("sd.img"));
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            byte[] buf = new byte[2048];
+            int read = fis.read(buf);
+            while(read > 0) {
+                baos.write(buf, 0, read);
+                read = fis.read(buf);
+            }
+            sdcontent = baos.toByteArray();
+        } catch (IOException ex) {
+            logger.log(Level.INFO, "Could not load image for SD card from file 'sd.img'");
+        }
+    }
+    
+
+    @Override
+    public void write(int address, int data) throws MemoryAccessException {
+        switch(address) {
+            case 0 :
+                writeData(data);
+                break;
+            case 1 :
+                writeCommand(data);
+                break;
+            case 2 :
+                this.lba0 = data;
+                computePosition();
+                break;
+            case 3 : 
+                this.lba1 = data;
+                computePosition();
+                break;
+            case 4 :
+                this.lba2 = data;
+                computePosition();
+                break;
+        }
+    }
+
+    @Override
+    public int read(int address) throws MemoryAccessException {
+        switch(address) {
+            case 0:
+                return readData();
+            case 1:
+                return readStatus();
+            case 2:
+                return lba0;
+            case 3:
+                return lba1;
+            case 4:
+                return lba2;
+            default:
+                return 0;
+        }
+    }
+    
+    private void computePosition() {
+        this.position = lba0 + (lba1 << 8) + (lba2 << 16);
+        // each sector is 512 bytes, so multiply accordingly
+        this.position <<= 9;
+     }
+    
+    private int readData() {
+        this.position %= this.sdcontent.length;
+        return this.sdcontent[this.position++];
+    }
+    
+    private void writeData(int data) {
+        this.position %= this.sdcontent.length;
+        this.sdcontent[this.position++] = (byte) data;
+    }
+    
+    private int readStatus() {
+        switch(this.status) {
+            case IDLE:
+                return 128;
+            case READ:
+                return 224;
+            default:
+                return 0;
+        }
+    }
+    
+    private void writeCommand(int data) {
+        this.command = data;
+        switch(this.command) {
+            case 0 :
+                this.status = Status.READ;
+                break;
+            case 1 :
+                this.status = Status.WRITE;
+                break;
+            default:
+                this.status = Status.IDLE;
+        }
+    }
+
+    @Override
+    public String toString() {
+        return getName() + "@" + String.format("%04X", this.getMemoryRange().startAddress);
+    }
+    
+}