/fs/

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/*
 * Optimized RAID-5 checksumming functions for MMX and SSE.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * You should have received a copy of the GNU General Public License
 * (for example /usr/src/linux/COPYING); if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


/*
 * Cache avoiding checksumming functions utilizing KNI instructions
 * Copyright (C) 1999 Zach Brown (with obvious credit due Ingo)
 */

/*
 * Based on
 * High-speed RAID5 checksumming functions utilizing SSE instructions.
 * Copyright (C) 1998 Ingo Molnar.
 */

/*
 * x86-64 changes / gcc fixes from Andi Kleen. 
 * Copyright 2002 Andi Kleen, SuSE Labs.
 *
 * This hasn't been optimized for the hammer yet, but there are likely
 * no advantages to be gotten from x86-64 here anyways.
 */

typedef struct { unsigned long a,b; } __attribute__((aligned(16))) xmm_store_t;

/* Doesn't use gcc to save the XMM registers, because there is no easy way to 
   tell it to do a clts before the register saving. */
#define XMMS_SAVE do {				\
	preempt_disable();			\
	asm volatile (				\
		"movq %%cr0,%0		;\n\t"	\
		"clts			;\n\t"	\
		"movups %%xmm0,(%1)	;\n\t"	\
		"movups %%xmm1,0x10(%1)	;\n\t"	\
		"movups %%xmm2,0x20(%1)	;\n\t"	\
		"movups %%xmm3,0x30(%1)	;\n\t"	\
		: "=&r" (cr0)			\
		: "r" (xmm_save) 		\
		: "memory");			\
} while(0)

#define XMMS_RESTORE do {			\
	asm volatile (				\
		"sfence			;\n\t"	\
		"movups (%1),%%xmm0	;\n\t"	\
		"movups 0x10(%1),%%xmm1	;\n\t"	\
		"movups 0x20(%1),%%xmm2	;\n\t"	\
		"movups 0x30(%1),%%xmm3	;\n\t"	\
		"movq 	%0,%%cr0	;\n\t"	\
		:				\
		: "r" (cr0), "r" (xmm_save)	\
		: "memory");			\
	preempt_enable();			\
} while(0)

#define OFFS(x)		"16*("#x")"
#define PF_OFFS(x)	"256+16*("#x")"
#define	PF0(x)		"	prefetchnta "PF_OFFS(x)"(%[p1])		;\n"
#define LD(x,y)		"       movaps   "OFFS(x)"(%[p1]), %%xmm"#y"	;\n"
#define ST(x,y)		"       movaps %%xmm"#y",   "OFFS(x)"(%[p1])	;\n"
#define PF1(x)		"	prefetchnta "PF_OFFS(x)"(%[p2])		;\n"
#define PF2(x)		"	prefetchnta "PF_OFFS(x)"(%[p3])		;\n"
#define PF3(x)		"	prefetchnta "PF_OFFS(x)"(%[p4])		;\n"
#define PF4(x)		"	prefetchnta "PF_OFFS(x)"(%[p5])		;\n"
#define PF5(x)		"	prefetchnta "PF_OFFS(x)"(%[p6])		;\n"
#define XO1(x,y)	"       xorps   "OFFS(x)"(%[p2]), %%xmm"#y"	;\n"
#define XO2(x,y)	"       xorps   "OFFS(x)"(%[p3]), %%xmm"#y"	;\n"
#define XO3(x,y)	"       xorps   "OFFS(x)"(%[p4]), %%xmm"#y"	;\n"
#define XO4(x,y)	"       xorps   "OFFS(x)"(%[p5]), %%xmm"#y"	;\n"
#define XO5(x,y)	"       xorps   "OFFS(x)"(%[p6]), %%xmm"#y"	;\n"


static void
xor_sse_2(unsigned long bytes, unsigned long *p1, unsigned long *p2)
{
        unsigned int lines = bytes >> 8;
	unsigned long cr0;
	xmm_store_t xmm_save[4];

	XMMS_SAVE;

        asm volatile (
#undef BLOCK
#define BLOCK(i) \
		LD(i,0)					\
			LD(i+1,1)			\
		PF1(i)					\
				PF1(i+2)		\
				LD(i+2,2)		\
					LD(i+3,3)	\
		PF0(i+4)				\
				PF0(i+6)		\
		XO1(i,0)				\
			XO1(i+1,1)			\
				XO1(i+2,2)		\
					XO1(i+3,3)	\
		ST(i,0)					\