Implement memory dumping for AXI slave models

src/test/scala/AxiSlaveModelDumper.scala

+package chisel.axiutils
+import Chisel._
+
+/**
+ * Helper companion: Dump complete memory of slave into file.
+ **/
+object AxiSlaveModelDumper {
+  /**
+   * Dumps the complete data of the AXI slave mode to a file.
+   * @param m The slave model to dump.
+   * @param filename Filename of dump file (paths will be created).
+   * @param lineWidth Number of bytes per line in file (default: 16).
+   * @param t Tester instance.
+   **/
+  def writeHexDump(m: AxiSlaveModel, filename: String, lineWidth: Int = 16)(implicit t: Tester[_]) {
+    require (lineWidth >= m.cfg.dataWidth / 8, "lineWidth (%d) must be >= dataWidth / 8 (%d)"
+        .format(lineWidth, m.cfg.dataWidth / 8))
+    require ((lineWidth * 8) % m.cfg.dataWidth == 0,
+        "lineWidth (%d) must be evenly divisible by word width (%d)"
+        .format(lineWidth * 8, m.cfg.dataWidth))
+
+    def hexAddr(addr: Int): String = "%%0%dx".format(m.cfg.addrWidth / 4).format(addr)
+    def hexByte(v: Int): String = "%02x ".format(v)
+    def asciiByte(v: Int): String = "%c".format(v) take 1
+    def toBytes(v: BigInt): Seq[Int] = (for (i <- 0 until m.cfg.dataWidth / 8) yield ((v >> (i * 8)) & 0xFF).toInt).reverse
+    def hexStr(vs: Seq[BigInt]): String = vs map toBytes reduce (_++_) map hexByte reduce (_++_)
+    def asciiStr(vs: Seq[BigInt]): String = vs map toBytes reduce (_++_) map asciiByte reduce (_++_)
+    def addrToIdx(addr: Int): Int = addr / (m.cfg.dataWidth / 8)
+    def idxToAddr(idx: Int): Int = idx * (m.cfg.dataWidth / 8)
+
+    java.nio.file.Paths.get(filename).toAbsolutePath.getParent.toFile.mkdirs()
+    val fw = new java.io.FileWriter(filename)
+
+    val lwords = (lineWidth * 8 / m.cfg.dataWidth)
+    println("m.cfg.size = %d, lwords = %d".format(m.cfg.size, lwords))
+
+    for (idx <- 0 until m.cfg.size if idx % lwords == 0;
+         val words = for (i <- 0 until lwords) yield t.peekAt(m.mem, idx + i)) {
+      fw.append("%s\t%s\t%s\n".format(hexAddr(idxToAddr(idx)), hexStr(words), asciiStr(words)))
+    }
+
+    fw.flush()
+    fw.close()
+  }
+}