operg722.c

ITU-T G.191中包含的G.722语音压缩编解码程序

 |                                                                           |
 |   Negate var1 with saturation, saturate in the case where input is -32768:|
 |                negate(var1) = sub(0,var1).                                |
 |                                                                           |
 |   Complexity weight : 1                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    var1                                                                   |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var_out <= 0x0000 7fff.                |
 |___________________________________________________________________________|
 */

Word16 
negate (var1)
Word16 var1;
{
  Word16          var_out;

  var_out = (var1 == MIN_16) ? MAX_16 : -var1;
  return (var_out);
}
/* ....................... end of negate() ............................ */


/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_add                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   32 bits addition of the two 32 bits variables (L_var1+L_var2) with      |
 |   overflow control and saturation; the result is set at [phone] when   |
 |   overflow occurs or at -214783648 when underflow occurs.                 |
 |                                                                           |
 |   Complexity weight : 2                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    L_var1   32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var3 <= 0x7fff ffff.                 |
 |                                                                           |
 |    L_var2   32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var3 <= 0x7fff ffff.                 |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    L_var_out                                                              |
 |             32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var_out <= 0x7fff ffff.              |
 |___________________________________________________________________________|
 */

Word32 
L_add (L_var1, L_var2)
Word32 L_var1;
Word32 L_var2;
{
  Word32          L_var_out;

  L_var_out = L_var1 + L_var2;

  if (((L_var1 ^ L_var2) & MIN_32) == 0L)
  {
    if ((L_var_out ^ L_var1) & MIN_32)
    {
      L_var_out = (L_var1 < 0L) ? MIN_32 : MAX_32;
    }
  }
  return (L_var_out);
}
/* ....................... end of L_add() ............................ */


/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_shr                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Arithmetically shift the 32 bit input L_var1 right var2 positions with  |
 |   sign extension. If var2 is negative, arithmetically shift L_var1 left   |
 |   by -var2 and zero fill the var2 LSB of the result. Saturate the result  |
 |   in case of underflows or overflows.                                     |
 |                                                                           |
 |   Complexity weight : 2                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    L_var1   32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var3 <= 0x7fff ffff.                 |
 |                                                                           |
 |    var2                                                                   |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    L_var_out                                                              |
 |             32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var_out <= 0x7fff ffff.              |
 |___________________________________________________________________________|
 */

Word32 
L_shr (L_var1, var2)
Word32 L_var1;
Word16 var2;
{
  Word32          L_var_out;

  if (var2 < (Word16) 0)
  {
    L_var_out = L_shl (L_var1, -var2);
  }
  else
  {
    if (var2 >= (Word16) 31)
    {
      L_var_out = (L_var1 < 0L) ? -1L : 0L;
    }
    else
    {
      if (L_var1 < 0L)
      {
	L_var_out = ~((~L_var1) >> var2);
      }
      else
      {
	L_var_out = L_var1 >> var2;
      }
    }
  }
  return (L_var_out);
}
/* ....................... end of L_shr() ............................ */


/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_shl                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Arithmetically shift the 32 bit input L_var1 left var2 positions. Zero  |
 |   fill the var2 LSB of the result. If var2 is negative, L_var1 right by   |
 |   -var2 arithmetically shift with sign extension. Saturate the result in  |
 |   case of underflows or overflows.                                        |
 |                                                                           |
 |   Complexity weight : 2                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    L_var1   32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var3 <= 0x7fff ffff.                 |
 |                                                                           |
 |    var2                                                                   |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    L_var_out                                                              |
 |             32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var_out <= 0x7fff ffff.              |
 |___________________________________________________________________________|
 */

Word32 
L_shl (L_var1, var2)
Word32 L_var1;
Word16 var2;
{
  Word32          L_var_out = 0L;

  if (var2 <= (Word16) 0)
  {
    L_var_out = L_shr (L_var1, -var2);
  }
  else
  {
    for (; var2 > (Word16) 0; var2--)
    {
      if (L_var1 > (Word32) 0X3fffffffL)
      {
	L_var_out = MAX_32;
	break;
      }
      else
      {
	if (L_var1 < (Word32) 0xc0000000L)
	{
	  L_var_out = MIN_32;
	  break;
	}
      }
      L_var1 *= 2L;
      L_var_out = L_var1;
    }
  }
  return (L_var_out);
}
/* ....................... end of L_shl() ............................ */