// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

#include "basicop.h"

/*

** int2 add( int2 var1, int2 var2 )

**

** Function performs the addition (var1+var2) with overflow control

** and saturation; the result is set at +32767 when overflow occurs

** or at -32768 when underflow occurs

**

** Input:

**   var1, var2

**     16-bit variables to be summed

**

** Output:

**   Sum of var and var2, see description above

**  

** Return value:

**   See above

*/

/*

** One way to implement saturation control to add and sub is to

** use temporary result that has enough bits to make overflow

** impossible and the limit the final result

*/

int2 add( int2 var1, int2 var2 )

{

  int4 L_temp;

  L_temp = (int4) var1 + var2;

  if ( L_temp < MININT2 )

    return MININT2;

  else if ( L_temp > MAXINT2 )

    return MAXINT2;

  else

    return (int2) L_temp;

}

/*

** int2 sub( int2 var1, int2 var2 )

**

** Function performs the subtraction (var1-var2) with overflow control

** and saturation; the result is set at +32767 when overflow occurs

** or at -32768 when underflow occurs

**

** Input:

**   var1, var2

**     16-bit variables to be summed

**

** Output:

**   Sum of var and var2, see description above

**  

** Return value:

**   See above

*/

int2 sub( int2 var1, int2 var2 )

{

  int4 L_temp;

  L_temp = (int4) var1 - var2;

  if ( L_temp < MININT2 )

    return MININT2;

  else if ( L_temp > MAXINT2 )

    return MAXINT2;

  else

    return (int2) L_temp;

}

/*

** int2 mult( int2 var1, int2 var2 )

**

** Function performs the multiplication of var1 by var2 and gives a

** 16-bit result which is scaled ie

**   mult( var1, var2 ) = (var1 times var2) >> 15

** and

**   mult( -32768, -32768 ) = 32767 

**

** Input:

**   var1, var2

**     16-bit variables to be multiplied

**

** Output:

**   Scaled result of multiplication

**  

** Return value:

**   See above

*/

int2 mult( int2 var1, int2 var2 )

{

  if ( ( var1 == MININT2 ) && ( var1 == var2 ) )

    return MAXINT2;

  else

    /* Note int4 cast of var1 to force 32-bit arithmetic */

   return( (int2) ( ( (int4) var1 * var2 ) >> 15 ) );

}

/*

** int2 abs_s( int2 var1 )

**

** Function returns absolute value of var1 with possible saturation:

**   abs( -32768 ) = 32767

**

** Input:

**   var1

**     16-bit variable

**

** Output:

**   absolute value of var1

**  

** Return value:

**   See above

*/

int2 abs_s( int2 var1 )

{

  if ( var1 == MININT2 )

    return MAXINT2;

  else

    return ( var1 > 0 ) ? var1 : int2 (-var1);

}

#ifdef L_MULTF

/* else implemented using macro (basicop.h) */

/*

** int4 L_mult( int2 var1, int2 var2 )

**

** Function performs the multiplication of var1 by var2 and gives a

** 32-bit result which is scaled by shifting result one bit left ie

**   L_mult( var1, var2 ) = (var1 times var2) << 1

**

**   L_mult( -32768, -32768 ) does not occur in algorithm

**

** Input:

**   var1, var2

**     16-bit variables to be multiplied

**

** Output:

**   Scaled result of multiplication

**  

** Return value:

**   See above

*/

int4 L_mult( int2 var1, int2 var2 )

{

  /* Note int4 cast of var1 to force 32-bit arithmetic */

  return ( L_shl( (int4) var1 * var2 ), 1 );

}

#endif /* L_MULTF */

/*

** int2 shr( int2 var1, int2 var2 )

**

** Function makes arithmetic var2-bit shift right of var1. If var2 is

** less than 0, this operation becomes arithmetic left shift of -var2

**

** Input:

**   var1

**     16-bit variable to be shifted

**   var2

**     amount of bits to be shifted

**

** Output:

**   16-bit value of shifted var1 is returned 

**  

** Return value:

**   See above

*/

int2 shr( int2 var1, int2 var2 )

{

  return shl( var1, int2 (-var2) );

}

/*

** int2 negate( int2 var1 )

**

** Function negates 16-bit variable var1. 

**   negate( -32768 ) = 32767

**

** Input:

**   var1

**     16-bit variable to be negated

**

** Output:

**   negated var1

**  

** Return value:

**   See above

*/

int2 negate( int2 var1 )

{

  if ( var1 == MININT2 )

    return MAXINT2;

  else

    return int2 (-var1);

}

/*

** int2 extract_h( int4 L_var1 )

**

** Function returns upper word (16 most significat bits) of the 

** 32-bit variable L_var1

**

** Input:

**   L_var1

**     32-bit variable

**

** Output:

**   upper word of the L_var1

**  

** Return value:

**   See above

*/

int2 extract_h( int4 L_var1 )

{

  return (int2) ( L_var1 >> 16 );

}

/*

** int2 extract_l( int4 L_var1 )

**

** Function returns lower word (16 least significat bits) of the

** 32-bit variable L_var1

**

** Input:

**   L_var1

**     32-bit variable

**

** Output:

**   lower word of L_var1

**  

** Return value:

**   See above

*/

int2 extract_l( int4 L_var1 )

{

  return (int2) (L_var1 & 0x0000ffff);

}

/*

** int4 L_mac( int4 L_var3, int2 var1, int2 var2 )

**

** Function multiplies var1 by var2 and shifts result left by one bit.

** Shifted result of multiplication is then added to L_var3 and result

** is returned. Summation is done with overflow control and saturation;

** the result is set at 2147483647 when overflow occurs and at

** -2147483648 when underflow occurs

**

** Input:

**   var1

**     16-bit multiplicant

**   var2

**     16-bit multiplier

**

**   L_var3

**     32-bit number that is summed with (var1*var2)<<1

**

** Output:

**   See description above

**  

** Return value:

**   See above

*/

int4 L_mac( int4 L_var3, int2 var1, int2 var2 )

{

  int4 L_temp;

  L_temp = ( (int4) var1 * var2 ) << 1;

  return L_add( L_var3, L_temp );

}

/*

** int4 L_add( int4 L_var1, int4 L_var2 )

**

** Function performs 32-bit addition of two 32-bit variables

** (L_var1 + L_var2) with overflow control and saturation; the

** result is set at 2147483647 when overflow occurs and at

** -2147483648 when underflow occurs

**

** Input:

**   L_var1, L_var2

**     32-bit variables to be summed

**

** Output:

**   32-bit result, see description above

**  

** Return value:

**   See above

*/

int4 L_add( int4 L_var1, int4 L_var2 )

{

  int4 L_temp1;

  int temp2; /* used for storing sign of L_var1 */

  L_temp1 = L_var1 + L_var2;

  /*

   * Overflow

   *   if sign(L_var1)==sign(L_var2) && sign(L_var1)!=sign(L_temp1).

   */

  if ( ( temp2 = (L_var1 < 0) ) == ( L_var2 < 0 ) 

    && ( temp2 != ( L_temp1 < 0 ) ) ) {

      L_temp1 = temp2 ? MININT4 : MAXINT4;

  }

  return L_temp1;

}

/*

** int4 L_sub( int4 L_var1, int4 L_var2 )

**

** Function performs 32-bit subtraction of two 32-bit variables

** (L_var1 - L_var2) with overflow control and saturation; the

** result is set at 2147483647 when overflow occurs and at

** -2147483648 when underflow occurs

**

** Input:

**   L_var1, L_var2

**     32-bit variables to be summed

**

** Output:

**   32-bit result, see description above

**  

** Return value:

**   See above

*/

int4 L_sub( int4 L_var1, int4 L_var2 )

{

  int4 L_temp1;

  int temp2;

  L_temp1 = L_var1 - L_var2;

  /*

   * Overflow

   *   if sign(L_var1)!=sign(L_var2) && sign(L_var1)!=sign(L_temp).

   */

  if ( ( temp2 = ( L_var1 < 0 ) ) != ( L_var2 < 0 ) 

    && ( temp2 != ( L_temp1 < 0 ) ) ) {

      L_temp1 = temp2 ? MININT4 : MAXINT4;

  }

  return L_temp1;

}

/*

** int2 mult_r( int2 var1, int2 var2 )

**

** Function performs the multiplication of var1 by var2 and gives a

** 16-bit result which is scaled with rounding ie

**   mult_r(var1, var2) = ((var1 times var2) + 16384) >> 15

** and

**   mult_r( -32768, -32768 ) = 32767 

**

** Input:

**   var1, var2

**     16-bit variables to be multiplied

**

** Output:

**   16-bit scaled result of multiplication

**  

** Return value:

**   See above

*/

int2 mult_r( int2 var1, int2 var2 )

{

  if ( ( var1 == MININT2 ) && ( var1 == var2 ) )

    return MAXINT2;

  else

    /* Note int4 cast of var1 to force 32-bit arithmetic */

    return( (int2) ( ( (int4) var1 * var2 + (int4) 16384 ) >> 15 ) );

}

/*

** int4 L_shr( int4 L_var1, int2 var2 )

**

** Function makes arithmetic var2-bit shift right of var1. If var2 is

** less than 0, this operation becomes arithmetic left shift of -var2

**

** Input:

**   L_var1

**     32-bit variable to be shifted

**   var2

**     amount of bits to be shifted

**

** Output:

**   16-bit value of shifted var1

**  

** Return value:

**   See above

*/

int4 L_shr( int4 L_var1, int2 var2 )

{

  return L_shl( L_var1, int2 (-var2) );

}

/*

** int4 L_deposit_h( int2 var1 )

**

** Function deposits the 16-bit variable var1 into the 16 most

** significant bits of the 32-bit word. The 16 least significant

** bits of the result are zeroed.

**

** Input:

**   var1

**     16-bit variable to be loaded to the upper 16 bits of

**     of the 32-bit variable

**

** Output:

**   32-bit number, see description above

**  

** Return value:

**   See above

*/

int4 L_deposit_h( int2 var1 )

{

  return ( (int4) var1 ) << 16;

}

/*

** int4 L_deposit_l( int2 var1 )

**

** Function deposits the 16-bit variable var1 into the 16 least

** significant bits of the 32-bit word. The 16 most significant bits

** of the result are sign extended.

**

** Input:

**   var1

**     16-bit variable to be converted to 32-bit variable

**

** Output:

**   32-bit variable that has same magnitude than var1

**  

** Return value:

**   See above

*/

int4 L_deposit_l( int2 var1 )

{

  return (int4) var1;

}

/*

** int2 norm_s( int2 var1 )

**

** Function produces number of left shifts needed to normalize the

** 16-bit variable var1 for positive values on the interval with

** minimum of 16384 and maximum of 32767 and for negative

** values on the interval with minimum of -32768 and maximum of

** -16384; in order to normalize the result, the following

** operation must be done:

**   norm_var1 = var1 << norm_s(var1)

**

** Input:

**   var1

**     16-bit variable which normalization factor is solved

**

** Output:

**   see description above

**  

** Return value:

**   See above

*/

int2 norm_s( int2 var1 )

{

  int2 cntr = 0;

  /* Special case when L_var1 == -32768: shift leads to underflow */

  if ( var1 == MININT2 )

    return 0;

  /* Special case when var1 == 0: shift does not change the value */

  else if ( var1 == 0 )

    return 0;

  else {

    if ( var1 < 0 ) {

      for ( ; var1 >= -16384; var1 *= 2 )

	cntr++;      

    }

    else {

      for ( ; var1 < 16384; var1 <<= 1 )

	cntr++;

    }

    return cntr;

  }

}

/*

** int2 norm_l( int4 L_var1 )

**

** Function produces number of left shifts needed to normalize the

** 32-bit variable L_var1 for positive values on the interval with

** minimum of 1073741824 and maximum of 2147483647 and for negative

** values on the interval with minimum of -2147483648 and maximum of

** -1073741824; in order to normalize the result, the following