Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 118 insertions, 0 deletions

diff --git a/include/asm-arm26/unaligned.h b/include/asm-arm26/unaligned.h
new file mode 100644
index 00000000000..d992782089f
--- /dev/null
+++ b/include/asm-arm26/unaligned.h
@@ -0,0 +1,118 @@
+#ifndef __ASM_ARM_UNALIGNED_H
+#define __ASM_ARM_UNALIGNED_H
+
+#include <asm/types.h>
+
+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_le(__p)					\
+	(__p[0] | __p[1] << 8)
+
+#define __get_unaligned_4_le(__p)					\
+	(__p[0] | __p[1] << 8 | __p[2] << 16 | __p[3] << 24)
+
+#define __get_unaligned_le(ptr)					\
+	({							\
+		__typeof__(*(ptr)) __v;				\
+		__u8 *__p = (__u8 *)(ptr);			\
+		switch (sizeof(*(ptr))) {			\
+		case 1:	__v = *(ptr);			break;	\
+		case 2: __v = __get_unaligned_2_le(__p);	break;	\
+		case 4: __v = __get_unaligned_4_le(__p);	break;	\
+		case 8: {					\
+				unsigned int __v1, __v2;	\
+				__v2 = __get_unaligned_4_le((__p+4)); \
+				__v1 = __get_unaligned_4_le(__p);	\
+				__v = ((unsigned long long)__v2 << 32 | __v1);	\
+			}					\
+			break;					\
+		default: __v = __bug_unaligned_x(__p);	break;	\
+		}						\
+		__v;						\
+	})
+
+static inline void __put_unaligned_2_le(__u32 __v, register __u8 *__p)
+{
+	*__p++ = __v;
+	*__p++ = __v >> 8;
+}
+
+static inline void __put_unaligned_4_le(__u32 __v, register __u8 *__p)
+{
+	__put_unaligned_2_le(__v >> 16, __p + 2);
+	__put_unaligned_2_le(__v, __p);
+}
+
+static inline void __put_unaligned_8_le(const unsigned long long __v, register __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_le(__v >> 32, __p+4);
+	__put_unaligned_4_le(__v, __p);
+}
+
+/*
+ * Try to store an unaligned value as efficiently as possible.
+ */
+#define __put_unaligned_le(val,ptr)					\
+	({							\
+		switch (sizeof(*(ptr))) {			\
+		case 1:						\
+			*(ptr) = (val);				\
+			break;					\
+		case 2: __put_unaligned_2_le((val),(__u8 *)(ptr));	\
+			break;					\
+		case 4:	__put_unaligned_4_le((val),(__u8 *)(ptr));	\
+			break;					\
+		case 8:	__put_unaligned_8_le((val),(__u8 *)(ptr)); \
+			break;					\
+		default: __bug_unaligned_x(ptr);		\
+			break;					\
+		}						\
+		(void) 0;					\
+	})
+
+/*
+ * Select endianness
+ */
+#define get_unaligned	__get_unaligned_le
+#define put_unaligned	__put_unaligned_le
+
+#endif