basic_op.c

g729b_pc.rar是G729语音压缩标准的附件B的C语言实现标准源代码。

 |                                                                           |
 |    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.              |
 |                                                                           |
 |   Caution :                                                               |
 |                                                                           |
 |    In some cases the Carry flag has to be cleared or set before using op- |
 |    rators which take into account its value.                              |
 |___________________________________________________________________________|
*/

Word32 L_macNs(Word32 L_var3, Word16 var1, Word16 var2)
  {
   Word32 L_var_out;

   L_var_out = L_mult(var1,var2);
   L_var_out = L_add_c(L_var3,L_var_out);
   return(L_var_out);
  }

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_msuNs                                                 |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Multiply var1 by var2 and shift the result left by 1. Subtract the 32   |
 |   bit result from L_var3 without saturation, return a 32 bit result. Ge-  |
 |   nerate carry and overflow values :                                      |
 |        L_msuNs(L_var3,var1,var2) = L_sub_c(L_var3,(L_mult(var1,var2)).    |
 |                                                                           |
 |   Complexity weight : 1                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    L_var3   32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= L_var3 <= 0x7fff ffff.                 |
 |                                                                           |
 |    var1                                                                   |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |    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.              |
 |                                                                           |
 |   Caution :                                                               |
 |                                                                           |
 |    In some cases the Carry flag has to be cleared or set before using op- |
 |    rators which take into account its value.                              |
 |___________________________________________________________________________|
*/

Word32 L_msuNs(Word32 L_var3, Word16 var1, Word16 var2)
  {
   Word32 L_var_out;

   L_var_out = L_mult(var1,var2);
   L_var_out = L_sub_c(L_var3,L_var_out);
   return(L_var_out);
  }

/*___________________________________________________________________________
 |                                                                           |
 |   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(Word32 L_var1, Word32 L_var2)
  {
   Word32 L_var_out;

   L_var_out = L_var1 + L_var2;

   if (((L_var1 ^ L_var2) & MIN_32) == 0)
     {
      if ((L_var_out ^ L_var1) & MIN_32)
        {
         L_var_out = (L_var1 < 0) ? MIN_32 : MAX_32;
         Overflow = 1;
        }
     }
   return(L_var_out);
  }

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_sub                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   32 bits subtraction 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_sub(Word32 L_var1, Word32 L_var2)
  {
   Word32 L_var_out;

   L_var_out = L_var1 - L_var2;

   if (((L_var1 ^ L_var2) & MIN_32) != 0)
     {
      if ((L_var_out ^ L_var1) & MIN_32)
        {
         L_var_out = (L_var1 < 0L) ? MIN_32 : MAX_32;
         Overflow = 1;
        }
     }
   return(L_var_out);
  }

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_add_c                                                 |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Performs 32 bits addition of the two 32 bits variables (L_var1+L_var2+C)|
 |   with carry. No saturation. Generate carry and Overflow values. The car- |
 |   ry and overflow values are binary variables which can be tested and as- |
 |   signed values.                                                          |
 |                                                                           |
 |   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.              |
 |                                                                           |
 |   Caution :                                                               |
 |                                                                           |
 |    In some cases the Carry flag has to be cleared or set before using op- |
 |    rators which take into account its value.                              |
 |___________________________________________________________________________|
*/
Word32 L_add_c(Word32 L_var1, Word32 L_var2)
  {
   Word32 L_var_out;
   Word32 L_test;
   Flag carry_int = 0;

   L_var_out = L_var1 + L_var2 + Carry;

   L_test = L_var1 + L_var2;

   if ((L_var1>0) && (L_var2 >0) && (L_test < 0))
     {
      Overflow = 1;
      carry_int = 0;
     }
   else
     {
      if ((L_var1<0) && (L_var2 <0) && (L_test >0))
        {
         Overflow = 1;
         carry_int = 1;
        }
      else
        {
         if (((L_var1 ^ L_var2) < 0) && (L_test > 0))