/*********************************************************************/
/* Copyright 2009, 2010 The University of Texas at Austin.           */
/* All rights reserved.                                              */
/*                                                                   */
/* Redistribution and use in source and binary forms, with or        */
/* without modification, are permitted provided that the following   */
/* conditions are met:                                               */
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/*   1. Redistributions of source code must retain the above         */
/*      copyright notice, this list of conditions and the following  */
/*      disclaimer.                                                  */
/*                                                                   */
/*   2. Redistributions in binary form must reproduce the above      */
/*      copyright notice, this list of conditions and the following  */
/*      disclaimer in the documentation and/or other materials       */
/*      provided with the distribution.                              */
/*                                                                   */
/*    THIS  SOFTWARE IS PROVIDED  BY THE  UNIVERSITY OF  TEXAS AT    */
/*    AUSTIN  ``AS IS''  AND ANY  EXPRESS OR  IMPLIED WARRANTIES,    */
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/* documentation are those of the authors and should not be          */
/* interpreted as representing official policies, either expressed   */
/* or implied, of The University of Texas at Austin.                 */
/*********************************************************************/

#include <stdio.h>
#include "common.h"

#define PREFETCHSIZE  8

#define a2	(a1 + 1)
#define a4	(a3 + 1)
#define a6	(a5 + 1)
#define a8	(a7 + 1)

int CNAME(BLASLONG n, BLASLONG k1, BLASLONG k2, FLOAT *a, BLASLONG lda, blasint *ipiv, FLOAT *buffer){

  BLASLONG i, j, ip1, ip2;
  blasint *piv;
  FLOAT *a1, *a3, *a5, *a7;
  FLOAT *b1, *b2, *b3, *b4;
  FLOAT *b5, *b6, *b7, *b8;
  FLOAT A1, A2, B1, B2, A3, A4, B3, B4;
  FLOAT A5, A6, B5, B6, A7, A8, B7, B8;

  a--;
  k1 --;

 ipiv += k1;

  if (n  <= 0) return 0;

  j = (n >> 2);
  if (j > 0) {
    do {
      piv = ipiv;

      a1 = a + k1 + 1;

      a3 = a1 + 1 * lda;
      a5 = a1 + 2 * lda;
      a7 = a1 + 3 * lda;

      ip1 = *(piv + 0);
      ip2 = *(piv + 1);
      piv += 2;

      b1 = a + ip1;
      b2 = a + ip2;

      b3 = b1 + 1 * lda;
      b4 = b2 + 1 * lda;
      b5 = b1 + 2 * lda;
      b6 = b2 + 2 * lda;
      b7 = b1 + 3 * lda;
      b8 = b2 + 3 * lda;

      i = ((k2 - k1) >> 1);

      if (i > 0) {
	do {

#ifdef __GNUC__
	  __builtin_prefetch(a1 + PREFETCHSIZE, 0, 0);
	  __builtin_prefetch(a3 + PREFETCHSIZE, 0, 0);
	  __builtin_prefetch(a5 + PREFETCHSIZE, 0, 0);
	  __builtin_prefetch(a7 + PREFETCHSIZE, 0, 0);
#endif

	  A1 = *a1;
	  A2 = *a2;
	  A3 = *a3;
	  A4 = *a4;
	  A5 = *a5;
	  A6 = *a6;
	  A7 = *a7;
	  A8 = *a8;

	  B1 = *b1;
	  B2 = *b2;
	  B3 = *b3;
	  B4 = *b4;
	  B5 = *b5;
	  B6 = *b6;
	  B7 = *b7;
	  B8 = *b8;

	  ip1 = *(piv + 0);
	  ip2 = *(piv + 1);
	  piv += 2;

	if (b1 == a1) {
	    if (b2 == a2) {
	      *(buffer + 0) = A1;
	      *(buffer + 1) = A3;
	      *(buffer + 2) = A5;
	      *(buffer + 3) = A7;

	      *(buffer + 4) = A2;
	      *(buffer + 5) = A4;
	      *(buffer + 6) = A6;
	      *(buffer + 7) = A8;
	    } else {
	      *(buffer + 0) = A1;
	      *(buffer + 1) = A3;
	      *(buffer + 2) = A5;
	      *(buffer + 3) = A7;

	      *(buffer + 4) = B2;
	      *(buffer + 5) = B4;
	      *(buffer + 6) = B6;
	      *(buffer + 7) = B8;

	      *b2 = A2;
	      *b4 = A4;
	      *b6 = A6;
	      *b8 = A8;
	    }
	} else
	  if (b1 == a2) {
	      if (b2 == a2) {
		*(buffer + 0) = A2;
		*(buffer + 1) = A4;
		*(buffer + 2) = A6;
		*(buffer + 3) = A8;
		*(buffer + 4) = A1;
		*(buffer + 5) = A3;
		*(buffer + 6) = A5;
		*(buffer + 7) = A7;
	      } else {
		*(buffer + 0) = A2;
		*(buffer + 1) = A4;
		*(buffer + 2) = A6;
		*(buffer + 3) = A8;
		*(buffer + 4) = B2;
		*(buffer + 5) = B4;
		*(buffer + 6) = B6;
		*(buffer + 7) = B8;
		*b2 = A1;
		*b4 = A3;
		*b6 = A5;
		*b8 = A7;
	      }
	  } else {
	      if (b2 == a2) {
		*(buffer + 0) = B1;
		*(buffer + 1) = B3;
		*(buffer + 2) = B5;
		*(buffer + 3) = B7;
		*(buffer + 4) = A2;
		*(buffer + 5) = A4;
		*(buffer + 6) = A6;
		*(buffer + 7) = A8;
		*b1 = A1;
		*b3 = A3;
		*b5 = A5;
		*b7 = A7;
	      } else
		if (b2 == b1) {
		  *(buffer + 0) = B1;
		  *(buffer + 1) = B3;
		  *(buffer + 2) = B5;
		  *(buffer + 3) = B7;
		  *(buffer + 4) = A1;
		  *(buffer + 5) = A3;
		  *(buffer + 6) = A5;
		  *(buffer + 7) = A7;
		  *b1 = A2;
		  *b3 = A4;
		  *b5 = A6;
		  *b7 = A8;
		} else {
		  *(buffer + 0) = B1;
		  *(buffer + 1) = B3;
		  *(buffer + 2) = B5;
		  *(buffer + 3) = B7;
		  *(buffer + 4) = B2;
		  *(buffer + 5) = B4;
		  *(buffer + 6) = B6;
		  *(buffer + 7) = B8;
		  *b1 = A1;
		  *b2 = A2;
		  *b3 = A3;
		  *b4 = A4;
		  *b5 = A5;
		  *b6 = A6;
		  *b7 = A7;
		  *b8 = A8;
		}
	  }

	 buffer += 8;

	  b1 = a + ip1;
	  b2 = a + ip2;

	  b3 = b1 + 1 * lda;
	  b4 = b2 + 1 * lda;
	  b5 = b1 + 2 * lda;
	  b6 = b2 + 2 * lda;
	  b7 = b1 + 3 * lda;
	  b8 = b2 + 3 * lda;

	  a1 += 2;
	  a3 += 2;
	  a5 += 2;
	  a7 += 2;

	i --;
	} while (i > 0);
      }

      i = ((k2 - k1) & 1);

      if (i > 0) {
	A1 = *a1;
	B1 = *b1;
	A3 = *a3;
	B3 = *b3;
	A5 = *a5;
	B5 = *b5;
	A7 = *a7;
	B7 = *b7;

	if (a1 == b1) {
	  *(buffer + 0) = A1;
	  *(buffer + 1) = A3;
	  *(buffer + 2) = A5;
	  *(buffer + 3) = A7;
	} else {
	  *(buffer + 0) = B1;
	  *(buffer + 1) = B3;
	  *(buffer + 2) = B5;
	  *(buffer + 3) = B7;
	  *b1 = A1;
	  *b3 = A3;
	  *b5 = A5;
	  *b7 = A7;
	}
	buffer += 4;
      }

      a += 4 * lda;

      j --;
    } while (j > 0);
  }

  if (n & 2) {
    piv = ipiv;

    a1 = a + k1 + 1;
    a3 = a1 + 1 * lda;

    ip1 = *(piv + 0);
    ip2 = *(piv + 1);
    piv += 2;

    b1 = a + ip1;
    b2 = a + ip2;

    b3 = b1 + 1 * lda;
    b4 = b2 + 1 * lda;

    i = ((k2 - k1) >> 1);

    if (i > 0) {
      do {
	A1 = *a1;
	A2 = *a2;
	A3 = *a3;
	A4 = *a4;

	B1 = *b1;
	B2 = *b2;
	B3 = *b3;
	B4 = *b4;

	ip1 = *(piv + 0);
	ip2 = *(piv + 1);
	piv += 2;

	if (b1 == a1) {
	    if (b2 == a2) {
	      *(buffer + 0) = A1;
	      *(buffer + 1) = A3;
	      *(buffer + 2) = A2;
	      *(buffer + 3) = A4;
	    } else {
	      *(buffer + 0) = A1;
	      *(buffer + 1) = A3;
	      *(buffer + 2) = B2;
	      *(buffer + 3) = B4;

	      *b2 = A2;
	      *b4 = A4;
	    }
	} else
	  if (b1 == a2) {
	      if (b2 == a2) {
		*(buffer + 0) = A2;
		*(buffer + 1) = A4;
		*(buffer + 2) = A1;
		*(buffer + 3) = A3;
	      } else {
		*(buffer + 0) = A2;
		*(buffer + 1) = A4;
		*(buffer + 2) = B2;
		*(buffer + 3) = B4;
		*b2 = A1;
		*b4 = A3;
	      }
	  } else {
	      if (b2 == a2) {
		*(buffer + 0) = B1;
		*(buffer + 1) = B3;
		*(buffer + 2) = A2;
		*(buffer + 3) = A4;
		*b1 = A1;
		*b3 = A3;
	      } else
		if (b2 == b1) {
		  *(buffer + 0) = B1;
		  *(buffer + 1) = B3;
		  *(buffer + 2) = A1;
		  *(buffer + 3) = A3;
		  *b1 = A2;
		  *b3 = A4;
		} else {
		  *(buffer + 0) = B1;
		  *(buffer + 1) = B3;
		  *(buffer + 2) = B2;
		  *(buffer + 3) = B4;
		  *b1 = A1;
		  *b2 = A2;
		  *b3 = A3;
		  *b4 = A4;
		}
	  }

	buffer += 4;

	b1 = a + ip1;
	b2 = a + ip2;

	b3 = b1 + 1 * lda;
	b4 = b2 + 1 * lda;

	a1 += 2;
	a3 += 2;

	i --;
      } while (i > 0);
    }

    i = ((k2 - k1) & 1);

    if (i > 0) {
      A1 = *a1;
      B1 = *b1;
      A3 = *a3;
      B3 = *b3;

      if (a1 == b1) {
	*(buffer + 0) = A1;
	*(buffer + 1) = A3;
      } else {
	*(buffer + 0) = B1;
	*(buffer + 1) = B3;
	*b1 = A1;
	*b3 = A3;
      }
      buffer += 2;
    }

    a += 2 * lda;
  }

  if (n & 1) {
    piv = ipiv;

    a1 = a + k1 + 1;

    ip1 = *(piv + 0);
    ip2 = *(piv + 1);
    piv += 2;

    b1 = a + ip1;
    b2 = a + ip2;

    i = ((k2 - k1) >> 1);

    if (i > 0) {
      do {
	A1 = *a1;
	A2 = *a2;
	B1 = *b1;
	B2 = *b2;

	ip1 = *(piv + 0);
	ip2 = *(piv + 1);
	piv += 2;

	if (b1 == a1) {
	    if (b2 == a2) {
	      *(buffer + 0) = A1;
	      *(buffer + 1) = A2;
	    } else {
	      *(buffer + 0) = A1;
	      *(buffer + 1) = B2;

	      *b2 = A2;
	    }
	} else
	  if (b1 == a2) {
	      if (b2 == a2) {
		*(buffer + 0) = A2;
		*(buffer + 1) = A1;
	      } else {
		*(buffer + 0) = A2;
		*(buffer + 1) = B2;
		*b2 = A1;
	      }
	  } else {
	      if (b2 == a2) {
		*(buffer + 0) = B1;
		*(buffer + 1) = A2;
		*b1 = A1;
	      } else
		if (b2 == b1) {
		  *(buffer + 0) = B1;
		  *(buffer + 1) = A1;
		  *b1 = A2;
		} else {
		  *(buffer + 0) = B1;
		  *(buffer + 1) = B2;
		  *b1 = A1;
		  *b2 = A2;
		}
	  }

	buffer += 2;

	b1 = a + ip1;
	b2 = a + ip2;

	a1 += 2;

	i --;
      } while (i > 0);
    }

    i = ((k2 - k1) & 1);

    if (i > 0) {
      A1 = *a1;
      B1 = *b1;

      if (a1 == b1) {
	*(buffer + 0) = A1;
      } else {
	*(buffer + 0) = B1;
	*b1 = A1;
      }
    }
  }

  return 0;
}