diff --git a/Makefile b/Makefile
index 8f441b0d..65b3c959 100644
--- a/Makefile
+++ b/Makefile
@@ -332,6 +332,7 @@ OBJS =	\
 	src/traps.o \
 	src/uaelib.o \
 	src/uaeresource.o \
+	src/vm.o \
 	src/zfile.o \
 	src/zfile_archive.o \
 	src/archivers/7z/7zAlloc.o \
diff --git a/src/include/uae/vm.h b/src/include/uae/vm.h
new file mode 100644
index 00000000..047b709c
--- /dev/null
+++ b/src/include/uae/vm.h
@@ -0,0 +1,49 @@
+/*
+ * Multi-platform virtual memory functions for UAE.
+ * Copyright (C) 2015 Frode Solheim
+ *
+ * Licensed under the terms of the GNU General Public License version 2.
+ * See the file 'COPYING' for full license text.
+ */
+
+#ifndef UAE_VM_H
+#define UAE_VM_H
+
+#include "uae/types.h"
+
+#define UAE_VM_WRITE 2
+#define UAE_VM_EXECUTE 4
+
+#define UAE_VM_32BIT (1 << 8)
+#define UAE_VM_WRITE_WATCH (1 << 9)
+#define UAE_VM_ALLOC_FAILED NULL
+
+/* Even though it looks like you can OR together vm protection values,
+ * do not do this. Not all combinations are supported (on Windows), and only
+ * a few combinations are implemented. Only use the following predefined
+ * constants to be safe. */
+
+#define UAE_VM_NO_ACCESS 0
+#define UAE_VM_READ 1
+#define UAE_VM_READ_WRITE (UAE_VM_READ | UAE_VM_WRITE)
+#define UAE_VM_READ_EXECUTE (UAE_VM_READ | UAE_VM_EXECUTE)
+#define UAE_VM_READ_WRITE_EXECUTE (UAE_VM_READ | UAE_VM_WRITE | UAE_VM_EXECUTE)
+
+#if 0
+void *uae_vm_alloc(uae_u32 size);
+void *uae_vm_alloc(uae_u32 size, int flags);
+#endif
+void *uae_vm_alloc(uae_u32 size, int flags, int protect);
+bool uae_vm_protect(void *address, int size, int protect);
+bool uae_vm_free(void *address, int size);
+
+void *uae_vm_reserve(uae_u32 size, int flags);
+void *uae_vm_reserve_fixed(void *address, uae_u32 size, int flags);
+void *uae_vm_commit(void *address, uae_u32 size, int protect);
+bool uae_vm_decommit(void *address, uae_u32 size);
+
+int uae_vm_page_size(void);
+
+// void *uae_vm_alloc_with_flags(uae_u32 size, int protect, int flags);
+
+#endif /* UAE_VM_H */
diff --git a/src/vm.cpp b/src/vm.cpp
new file mode 100644
index 00000000..54ad0ead
--- /dev/null
+++ b/src/vm.cpp
@@ -0,0 +1,461 @@
+/*
+ * Multi-platform virtual memory functions for UAE.
+ * Copyright (C) 2015 Frode Solheim
+ *
+ * Licensed under the terms of the GNU General Public License version 2.
+ * See the file 'COPYING' for full license text.
+ */
+
+#include "sysconfig.h"
+#include "sysdeps.h"
+#include "uae/vm.h"
+#include "options.h"
+#include "memory.h"
+#ifdef _WIN32
+
+#else
+#include <sys/mman.h>
+#endif
+#ifdef HAVE_SYS_PARAM_H
+#include <sys/param.h>
+#endif
+#if defined(__APPLE__)
+#include <sys/sysctl.h>
+#endif
+
+#if defined(LINUX) && defined(CPU_x86_64)
+#define HAVE_MAP_32BIT 1
+#endif
+
+// #define CLEAR_MEMORY_ON_COMMIT
+
+// #define LOG_ALLOCATIONS
+// #define TRACK_ALLOCATIONS
+
+#ifdef TRACK_ALLOCATIONS
+
+struct alloc_size {
+	void *address;
+	uae_u32 size;
+};
+
+#define MAX_ALLOCATIONS 2048
+/* A bit inefficient, but good enough for few and rare allocs. Storing
+ * the size at the start of the allocated memory would be better, but this
+ * could be awkward if/when you want to allocate page-aligned memory. */
+static struct alloc_size alloc_sizes[MAX_ALLOCATIONS];
+
+static void add_allocation(void *address, uae_u32 size)
+{
+	uae_log("VM: add_allocation %p (%d)\n", address, size);
+	for (int i = 0; i < MAX_ALLOCATIONS; i++) {
+		if (alloc_sizes[i].address == NULL) {
+			alloc_sizes[i].address = address;
+			alloc_sizes[i].size = size;
+			return;
+		}
+	}
+	abort();
+}
+
+static uae_u32 find_allocation(void *address)
+{
+	for (int i = 0; i < MAX_ALLOCATIONS; i++) {
+		if (alloc_sizes[i].address == address) {
+			return alloc_sizes[i].size;
+		}
+	}
+	abort();
+}
+
+static uae_u32 remove_allocation(void *address)
+{
+	for (int i = 0; i < MAX_ALLOCATIONS; i++) {
+		if (alloc_sizes[i].address == address) {
+			alloc_sizes[i].address = NULL;
+			uae_u32 size = alloc_sizes[i].size;
+			alloc_sizes[i].size = 0;
+			return size;
+		}
+	}
+	abort();
+}
+
+#endif /* TRACK_ALLOCATIONS */
+
+static int protect_to_native(int protect)
+{
+#ifdef _WIN32
+	if (protect == UAE_VM_NO_ACCESS) return PAGE_NOACCESS;
+	if (protect == UAE_VM_READ) return PAGE_READONLY;
+	if (protect == UAE_VM_READ_WRITE) return PAGE_READWRITE;
+	if (protect == UAE_VM_READ_EXECUTE) return PAGE_EXECUTE_READ;
+	if (protect == UAE_VM_READ_WRITE_EXECUTE) return PAGE_EXECUTE_READWRITE;
+	uae_log("VM: Invalid protect value %d\n", protect);
+	return PAGE_NOACCESS;
+#else
+	if (protect == UAE_VM_NO_ACCESS) return PROT_NONE;
+	if (protect == UAE_VM_READ) return PROT_READ;
+	if (protect == UAE_VM_READ_WRITE) return PROT_READ | PROT_WRITE;
+	if (protect == UAE_VM_READ_EXECUTE) return PROT_READ | PROT_EXEC;
+	if (protect == UAE_VM_READ_WRITE_EXECUTE) {
+		return PROT_READ | PROT_WRITE | PROT_EXEC;
+	}
+	write_log("VM: Invalid protect value %d\n", protect);
+	return PROT_NONE;
+#endif
+}
+
+static const char *protect_description(int protect)
+{
+	if (protect == UAE_VM_NO_ACCESS) return "NO_ACCESS";
+	if (protect == UAE_VM_READ) return "READ";
+	if (protect == UAE_VM_READ_WRITE) return "READ_WRITE";
+	if (protect == UAE_VM_READ_EXECUTE) return "READ_EXECUTE";
+	if (protect == UAE_VM_READ_WRITE_EXECUTE) return "READ_WRITE_EXECUTE";
+	return "UNKNOWN";
+}
+
+int uae_vm_page_size(void)
+{
+	static int page_size = 0;
+	if (page_size == 0) {
+#ifdef _WIN32
+		SYSTEM_INFO si;
+		GetSystemInfo(&si);
+		page_size = si.dwPageSize;
+#else
+		page_size = sysconf(_SC_PAGESIZE);
+#endif
+	}
+	return page_size;
+}
+
+static void *try_alloc_32bit(uae_u32 size, int native_flags, int native_protect,
+							uae_u8 *p, uae_u8 *p_end)
+{
+	if (p_end <= p) {
+		return NULL;
+	}
+	if ((uintptr_t) p % uae_vm_page_size() != 0) {
+		/* Round up to the nearest page size */
+		p += uae_vm_page_size() - (uintptr_t) p % uae_vm_page_size();
+	}
+	void *address = NULL;
+	int step = uae_vm_page_size();
+	if (size > 1024 * 1024) {
+		/* Reserve some space for smaller allocations */
+		p += 32 * 1024 * 1024;
+		step = 1024 * 1024;
+	}
+#ifdef HAVE_MAP_32BIT
+	address = mmap(0, size, native_protect, native_flags | MAP_32BIT, -1, 0);
+	if (address == MAP_FAILED) {
+		address = NULL;
+	}
+#endif
+	while (address == NULL) {
+		if (p > p_end) {
+			break;
+		}
+#ifdef _WIN32
+		address = VirtualAlloc(p, size, native_flags, native_protect);
+#else
+		address = mmap(p, size, native_protect, native_flags, -1, 0);
+#ifdef LOG_ALLOCATIONS
+		write_log("VM: trying %p step is 0x%x = %p\n", p, step, address);
+#endif
+		if (address == MAP_FAILED) {
+			address = NULL;
+		} else if (((uintptr_t) address) + size > (uintptr_t) 0xffffffff) {
+			munmap(address, size);
+			address = NULL;
+		}
+#endif
+		p += step;
+	}
+	return address;
+}
+
+static void *uae_vm_alloc_with_flags(uae_u32 size, int flags, int protect)
+{
+	void *address = NULL;
+	static bool first_allocation = true;
+	if (first_allocation) {
+		/* FIXME: log contents of /proc/self/maps on Linux */
+		/* FIXME: use VirtualQuery function on Windows? */
+		first_allocation = false;
+	}
+#ifdef LOG_ALLOCATIONS
+	uae_log("VM: Allocate 0x%-8x bytes [%d] (%s)\n",
+			size, flags, protect_description(protect));
+#endif
+
+#ifdef _WIN32
+	int native_flags = MEM_COMMIT | MEM_RESERVE;
+	if (flags & UAE_VM_WRITE_WATCH) {
+		native_flags |= MEM_WRITE_WATCH;
+	}
+	int native_protect = protect_to_native(protect);
+#else
+	int native_flags = MAP_PRIVATE | MAP_ANON;
+	int native_protect = protect_to_native(protect);
+#endif
+
+#ifndef CPU_64_BIT
+	flags &= ~UAE_VM_32BIT;
+#endif
+	if (flags & UAE_VM_32BIT) {
+		/* Stupid algorithm to find available space, but should
+		 * work well enough when there is not a lot of allocations. */
+		/* FIXME: Consider allocating a bigger chunk of memory, and manually
+		 * keep track of allocations. */
+#if 1
+		if (!address) {
+			address = try_alloc_32bit(
+						size, native_flags, native_protect,
+						(uae_u8 *) 0x40000000, natmem_reserved - size);
+		}
+#endif
+		if (!address && natmem_reserved < (uae_u8 *) 0x60000000) {
+			address = try_alloc_32bit(
+						size, native_flags, native_protect,
+						(uae_u8 *) natmem_reserved + natmem_reserved_size,
+						(uae_u8 *) 0xffffffff - size + 1);
+		}
+		if (!address) {
+			address = try_alloc_32bit(
+						size, native_flags, native_protect,
+						(uae_u8 *) 0x20000000,
+						min((uae_u8 *) 0x40000000, natmem_reserved - size));
+		}
+	} else {
+#ifdef _WIN32
+		address = VirtualAlloc(NULL, size, native_flags, native_protect);
+#else
+		address = mmap(0, size, native_protect, native_flags, -1, 0);
+		if (address == MAP_FAILED) {
+			address = NULL;
+		}
+#endif
+	}
+
+	if (address == NULL) {
+		write_log("VM: uae_vm_alloc(%u, %d, %d) mmap failed (%d)\n",
+		    size, flags, protect, errno);
+	    return NULL;
+	}
+#ifdef TRACK_ALLOCATIONS
+	add_allocation(address, size);
+#endif
+#ifdef LOG_ALLOCATIONS
+	uae_log("VM: %p\n", address);
+#endif
+	return address;
+}
+
+void *uae_vm_alloc(uae_u32 size, int flags, int protect)
+{
+	return uae_vm_alloc_with_flags(size, flags, protect);
+}
+
+static bool do_protect(void *address, int size, int protect)
+{
+#ifdef TRACK_ALLOCATIONS
+	uae_u32 allocated_size = find_allocation(address);
+	assert(allocated_size == size);
+#endif
+#ifdef _WIN32
+	DWORD old;
+	if (VirtualProtect(address, size, protect_to_native(protect), &old) == 0) {
+		uae_log("VM: uae_vm_protect(%p, %d, %d) VirtualProtect failed (%d)\n",
+				address, size, protect, GetLastError());
+		return false;
+	}
+#else
+	if (mprotect(address, size, protect_to_native(protect)) != 0) {
+		write_log("VM: uae_vm_protect(%p, %d, %d) mprotect failed (%d)\n",
+				address, size, protect, errno);
+		return false;
+	}
+#endif
+	return true;
+}
+
+bool uae_vm_protect(void *address, int size, int protect)
+{
+	return do_protect(address, size, protect);
+}
+
+static bool do_free(void *address, int size)
+{
+#ifdef TRACK_ALLOCATIONS
+	uae_u32 allocated_size = remove_allocation(address);
+	assert(allocated_size == size);
+#endif
+#ifdef _WIN32
+	return VirtualFree(address, 0, MEM_RELEASE) != 0;
+#else
+	if (munmap(address, size) != 0) {
+		write_log("VM: uae_vm_free(%p, %d) munmap failed (%d)\n",
+				address, size, errno);
+		return false;
+	}
+#endif
+	return true;
+}
+
+bool uae_vm_free(void *address, int size)
+{
+	write_log("VM: Free     0x%-8x bytes at %p\n", size, address);
+	return do_free(address, size);
+}
+
+static void *try_reserve(uintptr_t try_addr, uae_u32 size, int flags)
+{
+	void *address = NULL;
+	if (try_addr) {
+		write_log("VM: Reserve  0x%-8x bytes, try address 0x%llx\n",
+				size, (uae_u64) try_addr);
+	} else {
+		write_log("VM: Reserve  0x%-8x bytes\n", size);
+	}
+#ifdef _WIN32
+	int va_type = MEM_RESERVE;
+	if (flags & UAE_VM_WRITE_WATCH) {
+		va_type |= MEM_WRITE_WATCH;
+	}
+	int va_protect = protect_to_native(UAE_VM_NO_ACCESS);
+	address = VirtualAlloc((void *) try_addr, size, va_type, va_protect);
+	if (address == NULL) {
+		return NULL;
+	}
+#else
+	int mmap_flags = MAP_PRIVATE | MAP_ANON;
+	address = mmap((void *) try_addr, size, PROT_NONE, mmap_flags, -1, 0);
+	if (address == MAP_FAILED) {
+		return NULL;
+	}
+#endif
+#ifdef CPU_64_BIT
+	if (flags & UAE_VM_32BIT) {
+		uintptr_t end = (uintptr_t) address + size;
+		if (address && end > (uintptr_t) 0x100000000ULL) {
+			uae_log("VM: Reserve  0x%-8x bytes, got address 0x%llx (> 32-bit)\n",
+					size, (uae_u64) (uintptr_t) address);
+#ifdef _WIN32
+			VirtualFree(address, 0, MEM_RELEASE);
+#else
+			munmap(address, size);
+#endif
+			return NULL;
+		}
+	}
+#endif
+	return address;
+}
+
+void *uae_vm_reserve(uae_u32 size, int flags)
+{
+#if 0
+	if (size > 768 * 1024 * 1024) {
+		return NULL;
+	}
+#endif
+	void *address = NULL;
+#ifdef _WIN32
+	address = try_reserve(0x80000000, size, flags);
+	if (address == NULL && (flags & UAE_VM_32BIT)) {
+		if (size <= 768 * 1024 * 1024) {
+			address = try_reserve(0x78000000 - size, size, flags);
+		}
+	}
+	if (address == NULL && (flags & UAE_VM_32BIT) == 0) {
+		address = try_reserve(0, size, flags);
+	}
+#else
+#ifdef CPU_64_BIT
+	if (flags & UAE_VM_32BIT) {
+#else
+	if (true) {
+#endif
+		uintptr_t try_addr = 0xffffffff - size + 1;
+		while (address == NULL) {
+			address = try_reserve(try_addr, size, flags);
+			if (address == NULL) {
+				try_addr -= 0x4000000;
+				if (try_addr < 0x20000000) {
+					break;
+				}
+				continue;
+			}
+		}
+	}
+	if (address == NULL && (flags & UAE_VM_32BIT) == 0) {
+		address = try_reserve(0, size, flags);
+	}
+#endif
+	if (address) {
+		write_log("VM: Reserve  0x%-8x bytes, got address 0x%llx\n",
+				size, (uae_u64) (uintptr_t) address);
+	} else {
+		write_log("VM: Reserve  0x%-8x bytes failed!\n", size);
+	}
+	return address;
+}
+
+void *uae_vm_reserve_fixed(void *want_addr, uae_u32 size, int flags)
+{
+	void *address = NULL;
+	write_log("VM: Reserve  0x%-8x bytes at %p (fixed)\n", size, want_addr);
+	address = try_reserve((uintptr_t) want_addr, size, flags);
+	if (address == NULL) {
+		write_log("VM: Reserve  0x%-8x bytes at %p failed!\n", size, want_addr);
+		return NULL;
+	}
+	if (address != want_addr) {
+		do_free(address, size);
+		return NULL;
+	}
+	write_log("VM: Reserve  0x%-8x bytes, got address 0x%llx\n",
+			size, (uae_u64) (uintptr_t) address);
+	return address;
+}
+
+void *uae_vm_commit(void *address, uae_u32 size, int protect)
+{
+	write_log("VM: Commit   0x%-8x bytes at %p (%s)\n",
+			size, address, protect_description(protect));
+#ifdef _WIN32
+	int va_type = MEM_COMMIT ;
+	int va_protect = protect_to_native(protect);
+	address = VirtualAlloc(address, size, va_type, va_protect);
+#else
+#ifdef CLEAR_MEMORY_ON_COMMIT
+	do_protect(address, size, UAE_VM_READ_WRITE);
+	memset(address, 0, size);
+#endif
+	do_protect(address, size, protect);
+#endif
+	return address;
+}
+
+bool uae_vm_decommit(void *address, uae_u32 size)
+{
+	write_log("VM: Decommit 0x%-8x bytes at %p\n", size, address);
+#ifdef _WIN32
+	return VirtualFree (address, size, MEM_DECOMMIT) != 0;
+#else
+    /* Re-map the memory so we get fresh unused pages (and the old ones can be
+     * released and physical memory reclaimed). We also assume that the new
+     * pages will be zero-initialized (tested on Linux and OS X). */
+    void *result = mmap(address, size, PROT_NONE,
+                        MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0);
+    if (result == MAP_FAILED) {
+		write_log("VM: Warning - could not re-map with MAP_FIXED at %p\n",
+                address);
+        do_protect(address, size, UAE_VM_NO_ACCESS);
+    }
+    return result != MAP_FAILED;
+#endif
+}