Moved main memory to machine module

[Mograsim.git] / net.mograsim.machine / src / net / mograsim / machine / standard / memory / WordAddressableMemory.java

diff --git a/net.mograsim.machine/src/net/mograsim/machine/standard/memory/WordAddressableMemory.java b/net.mograsim.machine/src/net/mograsim/machine/standard/memory/WordAddressableMemory.java
new file mode 100644 (file)
index 0000000..719c993
--- /dev/null
+++ b/net.mograsim.machine/src/net/mograsim/machine/standard/memory/WordAddressableMemory.java
@@ -0,0 +1,80 @@
+package net.mograsim.machine.standard.memory;
+
+import java.util.Arrays;
+import java.util.HashMap;
+
+import net.mograsim.logic.core.types.Bit;
+import net.mograsim.logic.core.types.BitVector;
+
+public class WordAddressableMemory
+{
+       private final int cellWidth;
+       private final long minimalAddress, maximalAddress;
+       private final int pageSize = 64;
+
+       private HashMap<Long, Page> pages;
+
+       public WordAddressableMemory(int cellWidth, long minimalAddress, long maximalAddress)
+       {
+               super();
+               this.cellWidth = cellWidth;
+               this.minimalAddress = minimalAddress;
+               this.maximalAddress = maximalAddress;
+               this.pages = new HashMap<>();
+       }
+
+       public void setCell(long address, BitVector b)
+       {
+               if (address < minimalAddress || address > maximalAddress)
+                       throw new IndexOutOfBoundsException(String.format("Memory address out of bounds! Minimum: %d Maximum: %d Actual: %d",
+                                       minimalAddress, maximalAddress, address));
+               long page = address / pageSize;
+               int offset = (int) (address % pageSize);
+               Page p = pages.get(Long.valueOf(page));
+               if (p == null)
+                       pages.put(page, p = new Page());
+               p.setCell(offset, b);
+       }
+
+       public BitVector getCell(long address)
+       {
+               long page = address / pageSize;
+               int offset = (int) (address % pageSize);
+               Page p = pages.get(Long.valueOf(page));
+               if (p == null)
+                       return BitVector.of(Bit.U, cellWidth);
+               return p.getCell(offset);
+       }
+
+       private class Page
+       {
+               private BitVector[] memory;
+
+               public Page()
+               {
+                       memory = new BitVector[pageSize];
+               }
+
+               public BitVector getCell(int index)
+               {
+                       BitVector b = memory[index];
+                       if (b == null)
+                               return BitVector.of(Bit.U, cellWidth);
+                       return memory[index];
+               }
+
+               public void setCell(int index, BitVector bits)
+               {
+                       if (bits.length() != cellWidth)
+                               throw new IllegalArgumentException(String.format(
+                                               "BitVector to be saved in memory cell has unexpected length. Expected: %d Actual: %d", cellWidth, bits.length()));
+                       memory[index] = bits;
+               }
+
+               @Override
+               public String toString()
+               {
+                       return Arrays.deepToString(memory);
+               }
+       }
+}