1 files changed, 96 insertions, 0 deletions
diff --git a/src/pkg/runtime/mheapmap32.c b/src/pkg/runtime/mheapmap32.c
new file mode 100644
index 000000000..420ca2d83
--- /dev/null
+++ b/src/pkg/runtime/mheapmap32.c
@@ -0,0 +1,96 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Heap map, 32-bit version
+// See malloc.h and mheap.c for overview.
+
+#include "runtime.h"
+#include "malloc.h"
+
+// 3-level radix tree mapping page ids to Span*.
+void
+MHeapMap_Init(MHeapMap *m, void *(*allocator)(size_t))
+{
+	m->allocator = allocator;
+}
+
+MSpan*
+MHeapMap_Get(MHeapMap *m, PageID k)
+{
+	int32 i1, i2;
+
+	i2 = k & MHeapMap_Level2Mask;
+	k >>= MHeapMap_Level2Bits;
+	i1 = k & MHeapMap_Level1Mask;
+	k >>= MHeapMap_Level1Bits;
+	if(k != 0)
+		throw("MHeapMap_Get");
+
+	return m->p[i1]->s[i2];
+}
+
+MSpan*
+MHeapMap_GetMaybe(MHeapMap *m, PageID k)
+{
+	int32 i1, i2;
+	MHeapMapNode2 *p2;
+
+	i2 = k & MHeapMap_Level2Mask;
+	k >>= MHeapMap_Level2Bits;
+	i1 = k & MHeapMap_Level1Mask;
+	k >>= MHeapMap_Level1Bits;
+	if(k != 0)
+		throw("MHeapMap_Get");
+
+	p2 = m->p[i1];
+	if(p2 == nil)
+		return nil;
+	return p2->s[i2];
+}
+
+void
+MHeapMap_Set(MHeapMap *m, PageID k, MSpan *s)
+{
+	int32 i1, i2;
+
+	i2 = k & MHeapMap_Level2Mask;
+	k >>= MHeapMap_Level2Bits;
+	i1 = k & MHeapMap_Level1Mask;
+	k >>= MHeapMap_Level1Bits;
+	if(k != 0)
+		throw("MHeapMap_Set");
+
+	m->p[i1]->s[i2] = s;
+}
+
+// Allocate the storage required for entries [k, k+1, ..., k+len-1]
+// so that Get and Set calls need not check for nil pointers.
+bool
+MHeapMap_Preallocate(MHeapMap *m, PageID k, uintptr len)
+{
+	uintptr end;
+	int32 i1;
+	MHeapMapNode2 *p2;
+
+	end = k+len;
+	while(k < end) {
+		if((k >> MHeapMap_TotalBits) != 0)
+			return false;
+		i1 = (k >> MHeapMap_Level2Bits) & MHeapMap_Level1Mask;
+
+		// first-level pointer
+		if(m->p[i1] == nil) {
+			p2 = m->allocator(sizeof *p2);
+			if(p2 == nil)
+				return false;
+			sys_memclr((byte*)p2, sizeof *p2);
+			m->p[i1] = p2;
+		}
+
+		// advance key past this leaf node
+		k = ((k >> MHeapMap_Level2Bits) + 1) << MHeapMap_Level2Bits;
+	}
+	return true;
+}
+