/* Copyright 2001 by the Trustees of Indiana University */

static void dn_mult( register Index i_C, register Index i_A, register Index i_B)
{
  if (outOfBounds(i_A) || outOfBounds(i_B)) {}
  else if (i_A >= offset)
    C_matrix[i_C-offset] += A_matrix[i_A-offset] * B_matrix[i_B-offset];
      /* Both assertions about cache refer to extreme corners of */
      /* the named quadrant. */
  else 
  {   /* Precondition: one extreme block of C_ne, A_nw, or B_ne in cache. */
    {{dn_mult( ne(i_C),   nw(i_A), ne(i_B)  );   /* Leaving C_ne_nw in cache. */
      up_mult( ne(i_C), ne(i_A),     se(i_B));}  /* Leaving B_se_ne in cache. */
     {dn_mult(   se(i_C),   se(i_A), se(i_B));   /* Leaving C_se_nw in cache. */
      up_mult(   se(i_C), sw(i_A), ne(i_B)  );}} /* Leaving A_sw_nw in cache. */
    {{up_mult( sw(i_C),   sw(i_A),   nw(i_B));   /* Leaving C_sw_nw in cache. */
      dn_mult( sw(i_C), se(i_A),   sw(i_B)  );}  /* Leaving B_sw_ne in cache. */
     {up_mult(   nw(i_C), ne(i_A), sw(i_B)  );   /* Leaving C_nw_nw in cache. */
      dn_mult(   nw(i_C),   nw(i_A), nw(i_B));}}
      /* Postcondition: extreme blocks of C_nw, A_nw, B_nw in cache. */
  }
}

static void up_mult( register Index i_C, register Index i_A, register Index i_B)
{
  if (outOfBounds(i_A) || outOfBounds(i_B)) {}
  else if (i_A >= offset)
    C_matrix[i_C-offset] += A_matrix[i_A-offset] * B_matrix[i_B-offset];
  else
  {   /* Precondition: one extreme block of C_nw,A_nw, or B_nw in cache. */
    {{up_mult(   nw(i_C),   nw(i_A), nw(i_B));   /* Leaving C_nw_ne in cache. */
      dn_mult(   nw(i_C), ne(i_A), sw(i_B)  );}  /* Leaving B_sw_nw in cache. */
     {up_mult( sw(i_C), se(i_A),   sw(i_B)  );   /* Leaving C_sw_ne in cache. */
      dn_mult( sw(i_C),   sw(i_A),   nw(i_B));}} /* Leaving A_sw_nw in cache. */
    {{dn_mult(   se(i_C), sw(i_A), ne(i_B)  );   /* Leaving C_se_nw in cache. */
      up_mult(   se(i_C),   se(i_A), se(i_B));}  /* Leaving B_se_ne in cache. */
     {dn_mult( ne(i_C), ne(i_A),     se(i_B));   /* Leaving C_ne_nw in cache. */
      up_mult( ne(i_C),   nw(i_A), ne(i_B)  );}}
      /* Postcondition: extreme blocks of C_ne, A_nw, B_ne in cache. */
  }
}