HPL_ladd.c 5.4 KB

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  1. /*
  2. * -- High Performance Computing Linpack Benchmark (HPL)
  3. * HPL - 2.0 - September 10, 2008
  4. * Antoine P. Petitet
  5. * University of Tennessee, Knoxville
  6. * Innovative Computing Laboratory
  7. * (C) Copyright 2000-2008 All Rights Reserved
  8. *
  9. * -- Copyright notice and Licensing terms:
  10. *
  11. * Redistribution and use in source and binary forms, with or without
  12. * modification, are permitted provided that the following conditions
  13. * are met:
  14. *
  15. * 1. Redistributions of source code must retain the above copyright
  16. * notice, this list of conditions and the following disclaimer.
  17. *
  18. * 2. Redistributions in binary form must reproduce the above copyright
  19. * notice, this list of conditions, and the following disclaimer in the
  20. * documentation and/or other materials provided with the distribution.
  21. *
  22. * 3. All advertising materials mentioning features or use of this
  23. * software must display the following acknowledgement:
  24. * This product includes software developed at the University of
  25. * Tennessee, Knoxville, Innovative Computing Laboratory.
  26. *
  27. * 4. The name of the University, the name of the Laboratory, or the
  28. * names of its contributors may not be used to endorse or promote
  29. * products derived from this software without specific written
  30. * permission.
  31. *
  32. * -- Disclaimer:
  33. *
  34. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  35. * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  36. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  37. * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY
  38. * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  39. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  40. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  41. * DATA OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  42. * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  43. * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  44. * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  45. * ---------------------------------------------------------------------
  46. */
  47. /*
  48. * Include files
  49. */
  50. #include "hpl.h"
  51. #ifdef STDC_HEADERS
  52. void HPL_ladd
  53. (
  54. int * J,
  55. int * K,
  56. int * I
  57. )
  58. #else
  59. void HPL_ladd
  60. ( J, K, I )
  61. int * J;
  62. int * K;
  63. int * I;
  64. #endif
  65. {
  66. /*
  67. * Purpose
  68. * =======
  69. *
  70. * HPL_ladd adds without carry two long positive integers K and J and
  71. * puts the result into I. The long integers I, J, K are encoded on 64
  72. * bits using an array of 2 integers. The 32-lower bits are stored in
  73. * the first entry of each array, the 32-higher bits in the second
  74. * entry.
  75. *
  76. * Arguments
  77. * =========
  78. *
  79. * J (local input) int *
  80. * On entry, J is an integer array of dimension 2 containing the
  81. * encoded long integer J.
  82. *
  83. * K (local input) int *
  84. * On entry, K is an integer array of dimension 2 containing the
  85. * encoded long integer K.
  86. *
  87. * I (local output) int *
  88. * On entry, I is an integer array of dimension 2. On exit, this
  89. * array contains the encoded long integer result.
  90. *
  91. * ---------------------------------------------------------------------
  92. */
  93. /*
  94. * .. Local Variables ..
  95. */
  96. unsigned int itmp0, itmp1;
  97. unsigned int ktmp0 = K[0] & 65535, ktmp1 = (unsigned)K[0] >> 16;
  98. unsigned int ktmp2 = K[1] & 65535, ktmp3 = (unsigned)K[1] >> 16;
  99. unsigned int jtmp0 = J[0] & 65535, jtmp1 = (unsigned)J[0] >> 16;
  100. unsigned int jtmp2 = J[1] & 65535, jtmp3 = (unsigned)J[1] >> 16;
  101. /* ..
  102. * .. Executable Statements ..
  103. */
  104. /*
  105. * K[1] K[0] K I[0] = (K[0]+J[0]) % 2^32
  106. * XXXX XXXX carry = (K[0]+J[0]) / 2^32
  107. *
  108. * + J[1] J[0] J I[1] = K[1] + J[1] + carry
  109. * XXXX XXXX I[1] = I[1] % 2^32
  110. * -------------
  111. * I[1] I[0]
  112. * 0XXX XXXX I
  113. */
  114. itmp0 = ktmp0 + jtmp0;
  115. itmp1 = itmp0 >> 16; I[0] = itmp0 - (itmp1 << 16 );
  116. itmp1 += ktmp1 + jtmp1; I[0] |= (itmp1 & 65535) << 16;
  117. itmp0 = (itmp1 >> 16) + ktmp2 + jtmp2;
  118. I[1] = itmp0 - ((itmp0 >> 16 ) << 16);
  119. itmp1 = (itmp0 >> 16) + ktmp3 + jtmp3;
  120. I[1] |= (itmp1 & 65535) << 16;
  121. /*
  122. * End of HPL_ladd
  123. */
  124. }