Enhance e820 memory map generation - include files missing from last commit.
diff --git a/src/memmap.c b/src/memmap.c
new file mode 100644
index 0000000..e7ebc2a
--- /dev/null
+++ b/src/memmap.c
@@ -0,0 +1,138 @@
+// Support for building memory maps suitable for int 15 e820 calls.
+//
+// Copyright (C) 2008  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "memmap.h" // struct e820entry
+#include "util.h" // dprintf.h
+
+// Temporary storage used during map building.
+static struct e820entry e820_list[64];
+static int e820_count;
+
+// Remove an entry from the e820_list.
+static void
+remove_e820(int i)
+{
+    e820_count--;
+    memmove(&e820_list[i], &e820_list[i+1]
+            , sizeof(e820_list[0]) * (e820_count - i));
+}
+
+// Insert an entry in the e820_list at the given position.
+static void
+insert_e820(int i, u64 start, u64 size, u32 type)
+{
+    if (e820_count >= ARRAY_SIZE(e820_list)) {
+        dprintf(1, "Overflowed e820 list!\n");
+        return;
+    }
+
+    memmove(&e820_list[i+1], &e820_list[i]
+            , sizeof(e820_list[0]) * (e820_count - i));
+    e820_count++;
+    struct e820entry *e = &e820_list[i];
+    e->start = start;
+    e->size = size;
+    e->type = type;
+}
+
+// Show the current e820_list.
+static void
+dump_map()
+{
+    dprintf(1, "e820 map has %d items:\n", e820_count);
+    int i;
+    for (i=0; i<e820_count; i++) {
+        struct e820entry *e = &e820_list[i];
+        u64 e_end = e->start + e->size;
+        dprintf(1, "  %d: %x%x - %x%x = %d\n", i
+                , (u32)(e->start >> 32), (u32)e->start
+                , (u32)(e_end >> 32), (u32)e_end
+                , e->type);
+    }
+}
+
+// Add a new entry to the list.  This scans for overlaps and keeps the
+// list sorted.
+void
+add_e820(u64 start, u64 size, u32 type)
+{
+    dprintf(8, "Add to e820 map: %x %x %d\n", (u32)start, (u32)size, type);
+
+    if (! size)
+        // Huh?  Nothing to do.
+        return;
+
+    u64 end = start + size;
+    int i;
+    for (i=0; i<e820_count; i++) {
+        struct e820entry *e = &e820_list[i];
+        if (end <= e->start)
+            // Simple insertion point.
+            break;
+        u64 e_end = e->start + e->size;
+        if (start >= e_end)
+            // No overlap.
+            continue;
+        // New item overlaps with an existing one.
+        if (start > e->start) {
+            e->size = start - e->start;
+            i++;
+            if (end < e_end)
+                // Need to split existing item
+                insert_e820(i, end, e_end - end, e->type);
+        }
+        insert_e820(i, start, size, type);
+        i++;
+        // Remove all existing items that are completely overlapped.
+        while (i<e820_count) {
+            e = &e820_list[i];
+            if (end <= e->start)
+                break;
+            e_end = e->start + e->size;
+            if (end < e_end) {
+                // Existing item not completely overlapped - adjust its start.
+                e->start = end;
+                e->size = e_end - e->start;
+                break;
+            }
+            remove_e820(i);
+        }
+        //dump_map();
+        return;
+    }
+    // Just insert item.
+    insert_e820(i, start, size, type);
+    //dump_map();
+}
+
+u32 bios_table_cur_addr, bios_table_end_addr;
+
+// Prep for memmap stuff - init bios table locations.
+void
+memmap_setup()
+{
+    bios_table_cur_addr = 0xf0000 | OFFSET_freespace2_start;
+    bios_table_end_addr = 0xf0000 | OFFSET_freespace2_end;
+    dprintf(1, "bios_table_addr: 0x%08x end=0x%08x\n",
+            bios_table_cur_addr, bios_table_end_addr);
+}
+
+// Copy the temporary e820 map info to its permanent location.
+void
+memmap_finalize()
+{
+    dump_map();
+
+    u32 msize = e820_count * sizeof(e820_list[0]);
+    if (bios_table_cur_addr + msize > bios_table_end_addr) {
+        dprintf(1, "No room for e820 map!\n");
+        return;
+    }
+    memcpy((void*)bios_table_cur_addr, e820_list, msize);
+    SET_EBDA(e820_loc, bios_table_cur_addr);
+    SET_EBDA(e820_count, e820_count);
+    bios_table_cur_addr += msize;
+}