base: Add support for merging of interleaved address ranges

This patch adds support for merging a vector of interleaved address
ranges into a contigous range. The functionality will be used in the
interconnect and the PhysicalMemory to transform interleaved memory
ranges to contigous ranges before passing them on.

The actual use of the merging is appearing in future patches.

1 files changed, 42 insertions, 0 deletions

diff --git a/src/base/addr_range.hh b/src/base/addr_range.hh
index edcc0bf2f..546d81611 100644
--- a/src/base/addr_range.hh
+++ b/src/base/addr_range.hh
@@ -45,6 +45,8 @@
 #ifndef __BASE_ADDR_RANGE_HH__
 #define __BASE_ADDR_RANGE_HH__
 
+#include <vector>
+
 #include "base/bitfield.hh"
 #include "base/cprintf.hh"
 #include "base/misc.hh"
@@ -87,6 +89,46 @@ class AddrRange
     {}
 
     /**
+     * Create an address range by merging a collection of interleaved
+     * ranges.
+     *
+     * @param ranges Interleaved ranges to be merged
+     */
+    AddrRange(const std::vector<AddrRange>& ranges)
+        : _start(1), _end(0), intlvHighBit(0), intlvBits(0), intlvMatch(0)
+    {
+        if (!ranges.empty()) {
+            // get the values from the first one and check the others
+            _start = ranges.front()._start;
+            _end = ranges.front()._end;
+            intlvHighBit = ranges.front().intlvHighBit;
+            intlvBits = ranges.front().intlvBits;
+
+            if (ranges.size() != (ULL(1) << intlvBits))
+                fatal("Got %d ranges spanning %d interleaving bits\n",
+                      ranges.size(), intlvBits);
+
+            uint8_t match = 0;
+            for (std::vector<AddrRange>::const_iterator r = ranges.begin();
+                 r != ranges.end(); ++r) {
+                if (!mergesWith(*r))
+                    fatal("Can only merge ranges with the same start, end "
+                          "and interleaving bits\n");
+
+                if (r->intlvMatch != match)
+                    fatal("Expected interleave match %d but got %d when "
+                          "merging\n", match, r->intlvMatch);
+                ++match;
+            }
+
+            // our range is complete and we can turn this into a
+            // non-interleaved range
+            intlvHighBit = 0;
+            intlvBits = 0;
+        }
+    }
+
+    /**
      * Determine if the range is interleaved or not.
      *
      * @return true if interleaved