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+/* MN10300 Unaligned memory access handling
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#ifndef _ASM_UNALIGNED_H
+#define _ASM_UNALIGNED_H
+
+#include <asm/types.h>
+
+#if 0
+extern int __bug_unaligned_x(void *ptr);
+
+/*
+ * What is the most efficient way of loading/storing an unaligned value?
+ *
+ * That is the subject of this file. Efficiency here is defined as
+ * minimum code size with minimum register usage for the common cases.
+ * It is currently not believed that long longs are common, so we
+ * trade efficiency for the chars, shorts and longs against the long
+ * longs.
+ *
+ * Current stats with gcc 2.7.2.2 for these functions:
+ *
+ * ptrsize get: code regs put: code regs
+ * 1 1 1 1 2
+ * 2 3 2 3 2
+ * 4 7 3 7 3
+ * 8 20 6 16 6
+ *
+ * gcc 2.95.1 seems to code differently:
+ *
+ * ptrsize get: code regs put: code regs
+ * 1 1 1 1 2
+ * 2 3 2 3 2
+ * 4 7 4 7 4
+ * 8 19 8 15 6
+ *
+ * which may or may not be more efficient (depending upon whether
+ * you can afford the extra registers). Hopefully the gcc 2.95
+ * is inteligent enough to decide if it is better to use the
+ * extra register, but evidence so far seems to suggest otherwise.
+ *
+ * Unfortunately, gcc is not able to optimise the high word
+ * out of long long >> 32, or the low word from long long << 32
+ */
+
+#define __get_unaligned_2(__p) \
+ (__p[0] | __p[1] << 8)
+
+#define __get_unaligned_4(__p) \
+ (__p[0] | __p[1] << 8 | __p[2] << 16 | __p[3] << 24)
+
+#define get_unaligned(ptr) \
+({ \
+ unsigned int __v1, __v2; \
+ __typeof__(*(ptr)) __v; \
+ __u8 *__p = (__u8 *)(ptr); \
+ \
+ switch (sizeof(*(ptr))) { \
+ case 1: __v = *(ptr); break; \
+ case 2: __v = __get_unaligned_2(__p); break; \
+ case 4: __v = __get_unaligned_4(__p); break; \
+ case 8: \
+ __v2 = __get_unaligned_4((__p+4)); \
+ __v1 = __get_unaligned_4(__p); \
+ __v = ((unsigned long long)__v2 << 32 | __v1); \
+ break; \
+ default: __v = __bug_unaligned_x(__p); break; \
+ } \
+ __v; \
+})
+
+
+static inline void __put_unaligned_2(__u32 __v, register __u8 *__p)
+{
+ *__p++ = __v;
+ *__p++ = __v >> 8;
+}
+
+static inline void __put_unaligned_4(__u32 __v, register __u8 *__p)
+{
+ __put_unaligned_2(__v >> 16, __p + 2);
+ __put_unaligned_2(__v, __p);
+}
+
+static inline void __put_unaligned_8(const unsigned long long __v, __u8 *__p)
+{
+ /*
+ * tradeoff: 8 bytes of stack for all unaligned puts (2
+ * instructions), or an extra register in the long long
+ * case - go for the extra register.
+ */
+ __put_unaligned_4(__v >> 32, __p + 4);
+ __put_unaligned_4(__v, __p);
+}
+
+/*
+ * Try to store an unaligned value as efficiently as possible.
+ */
+#define put_unaligned(val, ptr) \
+ ({ \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ *(ptr) = (val); \
+ break; \
+ case 2: \
+ __put_unaligned_2((val), (__u8 *)(ptr)); \
+ break; \
+ case 4: \
+ __put_unaligned_4((val), (__u8 *)(ptr)); \
+ break; \
+ case 8: \
+ __put_unaligned_8((val), (__u8 *)(ptr)); \
+ break; \
+ default: \
+ __bug_unaligned_x(ptr); \
+ break; \
+ } \
+ (void) 0; \
+ })
+
+
+#else
+
+#define get_unaligned(ptr) (*(ptr))
+#define put_unaligned(val, ptr) ({ *(ptr) = (val); (void) 0; })
+
+#endif
+
+#endif