1 files changed, 98 insertions, 0 deletions
diff --git a/arch/arc/include/asm/swab.h b/arch/arc/include/asm/swab.h
new file mode 100644
index 0000000..095599a
--- /dev/null
+++ b/arch/arc/include/asm/swab.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * vineetg: May 2011
+ *  -Support single cycle endian-swap insn in ARC700 4.10
+ *
+ * vineetg: June 2009
+ *  -Better htonl implementation (5 instead of 9 ALU instructions)
+ *  -Hardware assisted single cycle bswap (Use Case of ARC custom instrn)
+ */
+
+#ifndef __ASM_ARC_SWAB_H
+#define __ASM_ARC_SWAB_H
+
+#include <linux/types.h>
+
+/* Native single cycle endian swap insn */
+#ifdef CONFIG_ARC_HAS_SWAPE
+
+#define __arch_swab32(x)		\
+({					\
+	unsigned int tmp = x;		\
+	__asm__(			\
+	"	swape	%0, %1	\n"	\
+	: "=r" (tmp)			\
+	: "r" (tmp));			\
+	tmp;				\
+})
+
+#else
+
+/* Several ways of Endian-Swap Emulation for ARC
+ * 0: kernel generic
+ * 1: ARC optimised "C"
+ * 2: ARC Custom instruction
+ */
+#define ARC_BSWAP_TYPE	1
+
+#if (ARC_BSWAP_TYPE == 1)		/******* Software only ********/
+
+/* The kernel default implementation of htonl is
+ *		return  x<<24 | x>>24 |
+ *		 (x & (__u32)0x0000ff00UL)<<8 | (x & (__u32)0x00ff0000UL)>>8;
+ *
+ * This generates 9 instructions on ARC (excluding the ld/st)
+ *
+ * 8051fd8c:	ld     r3,[r7,20]	; Mem op : Get the value to be swapped
+ * 8051fd98:	asl    r5,r3,24		; get  3rd Byte
+ * 8051fd9c:	lsr    r2,r3,24		; get  0th Byte
+ * 8051fda0:	and    r4,r3,0xff00
+ * 8051fda8:	asl    r4,r4,8		; get 1st Byte
+ * 8051fdac:	and    r3,r3,0x00ff0000
+ * 8051fdb4:	or     r2,r2,r5		; combine 0th and 3rd Bytes
+ * 8051fdb8:	lsr    r3,r3,8		; 2nd Byte at correct place in Dst Reg
+ * 8051fdbc:	or     r2,r2,r4		; combine 0,3 Bytes with 1st Byte
+ * 8051fdc0:	or     r2,r2,r3		; combine 0,3,1 Bytes with 2nd Byte
+ * 8051fdc4:	st     r2,[r1,20]	; Mem op : save result back to mem
+ *
+ * Joern suggested a better "C" algorithm which is great since
+ * (1) It is portable to any architecure
+ * (2) At the same time it takes advantage of ARC ISA (rotate intrns)
+ */
+
+#define __arch_swab32(x)					\
+({	unsigned long __in = (x), __tmp;			\
+	__tmp = __in << 8 | __in >> 24; /* ror tmp,in,24 */	\
+	__in = __in << 24 | __in >> 8; /* ror in,in,8 */	\
+	__tmp ^= __in;						\
+	__tmp &= 0xff00ff;					\
+	__tmp ^ __in;						\
+})
+
+#elif (ARC_BSWAP_TYPE == 2)	/* Custom single cycle bwap instruction */
+
+#define __arch_swab32(x)						\
+({									\
+	unsigned int tmp = x;						\
+	__asm__(							\
+	"	.extInstruction	bswap, 7, 0x00, SUFFIX_NONE, SYNTAX_2OP	\n"\
+	"	bswap  %0, %1						\n"\
+	: "=r" (tmp)							\
+	: "r" (tmp));							\
+	tmp;								\
+})
+
+#endif /* ARC_BSWAP_TYPE=zzz */
+
+#endif /* CONFIG_ARC_HAS_SWAPE */
+
+#if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
+#define __SWAB_64_THRU_32__
+#endif
+
+#endif