/*********************************************************************/
/* 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,    */
/*    INCLUDING, BUT  NOT LIMITED  TO, THE IMPLIED  WARRANTIES OF    */
/*    MERCHANTABILITY  AND FITNESS FOR  A PARTICULAR  PURPOSE ARE    */
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/*                                                                   */
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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"

int CNAME(BLASLONG m, BLASLONG n, FLOAT *a, BLASLONG lda, BLASLONG posX, BLASLONG posY, FLOAT *b){

  BLASLONG i, js, offset;

  FLOAT data01, data02, data03, data04;
  FLOAT *ao1, *ao2;

  lda *= 2;

  js = (n >> 1);
  while (js > 0){
    offset = posX - posY;
    
    if (offset >  0) ao1 = a + posY * 2 + (posX + 0) * lda; else ao1 = a + (posX + 0) * 2 + posY * lda;
    if (offset > -1) ao2 = a + posY * 2 + (posX + 1) * lda; else ao2 = a + (posX + 1) * 2 + posY * lda;

    i     = m;

    while (i > 0) {
      data01 = *(ao1 + 0);
      data02 = *(ao1 + 1);
      data03 = *(ao2 + 0);
      data04 = *(ao2 + 1);
      
      if (offset >   0) ao1 += 2; else ao1 += lda;
      if (offset >  -1) ao2 += 2; else ao2 += lda;

      if (offset > 0) {
	b[ 0] = data01;
	b[ 1] = -data02;
	b[ 2] = data03;
	b[ 3] = -data04;
      } else
	if (offset < -1) {
	  b[ 0] = data01;
	  b[ 1] = data02;
	  b[ 2] = data03;
	  b[ 3] = data04;
	} else {
	  switch (offset) {
	  case  0 :
	    b[ 0] = data01;
	    b[ 1] = ZERO;
	    b[ 2] = data03;
	    b[ 3] = -data04;
	    break;
	  case -1 :
	    b[ 0] = data01;
	    b[ 1] = data02;
	    b[ 2] = data03;
	    b[ 3] = ZERO;
	    break;
	  }
	}

      b += 4;

      offset --;
      i --;
    }

    posX += 2;
    js --;
  }

  if (n & 1) {

    offset = posX - posY;
    
    if (offset >  0) ao1 = a + posY * 2 + (posX + 0) * lda; else ao1 = a + (posX + 0) * 2 + posY * lda;

    i     = m;

    while (i > 0) {
      data01 = *(ao1 + 0);
      data02 = *(ao1 + 1);
      
      if (offset >   0) ao1 += 2; else ao1 += lda;

      if (offset > 0) {
	b[ 0] = data01;
	b[ 1] = -data02;
      } else
	if (offset < 0) {
	  b[ 0] = data01;
	  b[ 1] = data02;
	} else {
	    b[ 0] = data01;
	    b[ 1] = ZERO;
	}

      b += 2;

      offset --;
      i --;
    }

  }

  return 0;
}
