📄 prototype.c
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{
Overflow = 0;
var_out = extract_l (L_var1);
}
return (var_out);
}
Word32 add2(Word32 a, Word32 b)
{
Word32 v1, v2;
v1 = (a + b) & (0x0FFFF);
v2 = ((a & 0xFFFF0000) + (b & 0xFFFF0000));
return (v1 | v2);
}
Word32 sub2(Word32 a, Word32 b)
{
Word32 v1, v2;
v1 = ((short) a - (short) b) & (0x0FFFF);
v2 = (((short) (a >> 16) - (short) (b >> 16)) << 16) & 0xFFFF0000;
return (v1 | v2);
}
Word32 max2(Word32 a, Word32 b)
{
Word32 v1, v2;
v1 = ((short) a > (short) b) ? (a & 0x0FFFF):(b & 0x0FFFF);
v2 = ((short) (a >> 16) > (short) (b >> 16)) ?
(a & 0xFFFF0000):(b & 0xFFFF0000);
return (v1 | v2);
}
Word32 min2(Word32 a, Word32 b)
{
Word32 v1, v2;
v1 = ((short) a < (short) b) ? (a & 0x0FFFF):(b & 0x0FFFF);
v2 = ((short) (a >> 16) < (short) (b >> 16)) ?
(a & 0xFFFF0000):(b & 0xFFFF0000);
return (v1 | v2);
}
/*___________________________________________________________________________
| |
| Function Name : add |
| |
| Purpose : |
| |
| Performs the addition (var1+var2) with overflow control and saturation;|
| the 16 bit result is set at +32767 when overflow occurs or at -32768 |
| when underflow occurs. |
| |
| Complexity weight : 1 |
| |
| Inputs : |
| |
| 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 : |
| |
| var_out |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var_out <= 0x0000 7fff. |
|___________________________________________________________________________|
*/
Word16 add (Word16 var1, Word16 var2)
{
Word16 var_out;
Word32 L_sum;
L_sum = (Word32) var1 + var2;
var_out = saturate (L_sum);
return (var_out);
}
/*___________________________________________________________________________
| |
| Function Name : sub |
| |
| Purpose : |
| |
| Performs the subtraction (var1+var2) with overflow control and satu- |
| ration; the 16 bit result is set at +32767 when overflow occurs or at |
| -32768 when underflow occurs. |
| |
| Complexity weight : 1 |
| |
| Inputs : |
| |
| 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 : |
| |
| var_out |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var_out <= 0x0000 7fff. |
|___________________________________________________________________________|
*/
Word16 sub (Word16 var1, Word16 var2)
{
Word16 var_out;
Word32 L_diff;
L_diff = (Word32) var1 - var2;
var_out = saturate (L_diff);
return (var_out);
}
/*___________________________________________________________________________
| |
| Function Name : abs_s |
| |
| Purpose : |
| |
| Absolute value of var1; abs_s(-32768) = 32767. |
| |
| 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 : 0x0000 0000 <= var_out <= 0x0000 7fff. |
|___________________________________________________________________________|
*/
Word16 abs_s (Word16 var1)
{
Word16 var_out;
if (var1 == (Word16) 0X8000)
{
var_out = MAX_16;
}
else
{
if (var1 < 0)
{
var_out = -var1;
}
else
{
var_out = var1;
}
}
return (var_out);
}
/*___________________________________________________________________________
| |
| Function Name : shl |
| |
| Purpose : |
| |
| Arithmetically shift the 16 bit input var1 left var2 positions.Zero fill|
| the var2 LSB of the result. If var2 is negative, arithmetically shift |
| var1 right by -var2 with sign extension. Saturate the result in case of |
| underflows or overflows. |
| |
| Complexity weight : 1 |
| |
| Inputs : |
| |
| 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 : |
| |
| var_out |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var_out <= 0x0000 7fff. |
|___________________________________________________________________________|
*/
Word16 shl (Word16 var1, Word16 var2)
{
Word16 var_out;
Word32 result;
if (var2 < 0)
var_out = shr (var1, -var2);
else
{
result = (Word32) var1 *((Word32) 1 << var2);
if ((var2 > 15 && var1 != 0) || (result != (Word32) ((Word16) result)))
{
Overflow = 1;
var_out = (var1 > 0) ? MAX_16 : MIN_16;
}
else
var_out = extract_l (result);
}
return (var_out);
}
/*___________________________________________________________________________
| |
| Function Name : shr |
| |
| Purpose : |
| |
| Arithmetically shift the 16 bit input var1 right var2 positions with |
| sign extension. If var2 is negative, arithmetically shift var1 left by |
| -var2 with sign extension. Saturate the result in case of underflows or |
| overflows. |
| |
| Complexity weight : 1 |
| |
| Inputs : |
| |
| 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 : |
| |
| var_out |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var_out <= 0x0000 7fff. |
|___________________________________________________________________________|
*/
Word16 shr (Word16 var1, Word16 var2)
{
Word16 var_out;
if (var2 < 0)
var_out = shl (var1, -var2);
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