(2006-08-06) rescue-bootcd

extra/syslinux-3.09/memdisk/e820func.c

@@ -0,0 +1,105 @@
+#ident "$Id: e820func.c,v 1.7 2004/12/14 22:46:25 hpa Exp $"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * e820func.c
+ *
+ * E820 range database manager
+ */
+
+#include <stdint.h>
+#include "memdisk.h"		/* For memset() */
+#include "e820.h"
+
+#define MAXRANGES	64
+/* All of memory starts out as one range of "indeterminate" type */
+struct e820range ranges[MAXRANGES];
+int nranges;
+
+
+void e820map_init(void)
+{
+  memset(ranges, 0, sizeof(ranges));
+  nranges = 1;
+  ranges[1].type = -1;
+}
+
+static void insertrange_at(int where, uint64_t start, uint32_t type)
+{
+  int i;
+
+  for ( i = nranges ; i > where ; i-- )
+    ranges[i] = ranges[i-1];
+  
+  ranges[where].start = start;
+  ranges[where].type  = type;
+
+  nranges++;
+  ranges[nranges].start = 0ULL;
+  ranges[nranges].type  = (uint32_t)-1;
+}
+
+void insertrange(uint64_t start, uint64_t len, uint32_t type)
+{
+  uint64_t last;
+  uint32_t oldtype;
+  int i, j;
+
+  /* Remove this to make len == 0 mean all of memory */
+  if ( len == 0 )
+    return;			/* Nothing to insert */
+  
+  last = start+len-1;		/* May roll over */
+
+  i = 0;
+  oldtype = -2;
+  while ( start > ranges[i].start && ranges[i].type != -1 ) {
+    oldtype = ranges[i].type;
+    i++;
+  }
+
+  /* Consider the replacement policy.  This current one is "overwrite." */
+
+  if ( start < ranges[i].start || ranges[i].type == -1 )
+    insertrange_at(i++, start, type);
+
+  while ( i == 0 || last > ranges[i].start-1 ) {
+    oldtype = ranges[i].type;
+    ranges[i].type = type;
+    i++;
+  }
+
+  if ( last < ranges[i].start-1 )
+    insertrange_at(i, last+1, oldtype);
+
+  /* Now the map is correct, but quite possibly not optimal.  Scan the
+     map for ranges which are redundant and remove them. */
+  i = j = 1;
+  oldtype = ranges[0].type;
+  while ( i < nranges ) {
+    if ( ranges[i].type == oldtype ) {
+      i++;
+    } else {
+      oldtype = ranges[i].type;
+      if ( i != j )
+	ranges[j] = ranges[i];
+      i++; j++;
+    }
+  }
+
+  if ( i != j ) {
+    ranges[j] = ranges[i];	/* Termination sentinel copy */
+    nranges -= (i-j);
+  }
+}
+