view libgsmefr/basicops.c @ 471:b5f8ea41362b

gsmrec-dump: report DHF matches
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 14 May 2024 07:25:06 +0000
parents 1c514150c033
children
line wrap: on
line source

/*
 * This C module is a stripped-down version made from ETSI basicop2.c,
 * reduced to just those functions which we are not inlining.
 */

/*___________________________________________________________________________
 |                                                                           |
 |   Include-Files                                                           |
 |___________________________________________________________________________|
*/

#include <stdint.h>
#include "typedef.h"
#include "namespace.h"
#include "basic_op.h"

/*___________________________________________________________________________
 |                                                                           |
 |   Functions                                                               |
 |___________________________________________________________________________|
*/

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_macNs                                                 |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Multiply var1 by var2 and shift the result left by 1. Add the 32 bit    |
 |   result to L_var3 without saturation, return a 32 bit result. Generate   |
 |   carry and overflow values :                                             |
 |        L_macNs(L_var3,var1,var2) = L_add_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     |
 |    operators 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     |
 |    operators 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_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     |
 |    operators 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))
        {
            if (L_test >= 0)
	    {
                Overflow = 1;
                carry_int = 1;
	    }
            else
	    {
                Overflow = 0;
                carry_int = 1;
	    }
        }
        else
        {
            if (((L_var1 ^ L_var2) < 0) && (L_test >= 0))
            {
                Overflow = 0;
                carry_int = 1;
            }
            else
            {
                Overflow = 0;
                carry_int = 0;
            }
        }
    }

    if (Carry)
    {
        if (L_test == MAX_32)
        {
            Overflow = 1;
            Carry = carry_int;
        }
        else
        {
            if (L_test == (Word32) 0xFFFFFFFFL)
            {
                Carry = 1;
            }
            else
            {
                Carry = carry_int;
            }
        }
    }
    else
    {
        Carry = carry_int;
    }

    return (L_var_out);
}

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_sub_c                                                 |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Performs 32 bits subtraction of the two 32 bits variables with carry    |
 |   (borrow) : L_var1-L_var2-C. No saturation. Generate carry and Overflow  |
 |   values. The carry and overflow values are binary variables which can    |
 |   be tested and assigned 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     |
 |    operators which take into account its value.                           |
 |___________________________________________________________________________|
*/

Word32 L_sub_c (Word32 L_var1, Word32 L_var2)
{
    Word32 L_var_out;
    Word32 L_test;
    Flag carry_int = 0;

    if (Carry)
    {
        Carry = 0;
        if (L_var2 != MIN_32)
        {
            L_var_out = L_add_c (L_var1, -L_var2);
        }
        else
        {
            L_var_out = L_var1 - L_var2;
            if (L_var1 > 0L)
            {
                Overflow = 1;
                Carry = 0;
            }
        }
    }
    else
    {
        L_var_out = L_var1 - L_var2 - (Word32) 0X00000001L;
        L_test = L_var1 - L_var2;

        if ((L_test < 0) && (L_var1 > 0) && (L_var2 < 0))
        {
            Overflow = 1;
            carry_int = 0;
        }
        else if ((L_test > 0) && (L_var1 < 0) && (L_var2 > 0))
        {
            Overflow = 1;
            carry_int = 1;
        }
        else if ((L_test > 0) && ((L_var1 ^ L_var2) > 0))
        {
            Overflow = 0;
            carry_int = 1;
        }
        if (L_test == MIN_32)
        {
            Overflow = 1;
            Carry = carry_int;
        }
        else
        {
            Carry = carry_int;
        }
    }

    return (L_var_out);
}

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : shr_r                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Same as shr(var1,var2) but with rounding. Saturate the result in case of|
 |   underflows or overflows :                                               |
 |    - If var2 is greater than zero :                                       |
 |          if (sub(shl(shr(var1,var2),1),shr(var1,sub(var2,1))))            |
 |          is equal to zero                                                 |
 |                     then                                                  |
 |                     shr_r(var1,var2) = shr(var1,var2)                     |
 |                     else                                                  |
 |                     shr_r(var1,var2) = add(shr(var1,var2),1)              |
 |    - If var2 is less than or equal to zero :                              |
 |                     shr_r(var1,var2) = shr(var1,var2).                    |
 |                                                                           |
 |   Complexity weight : 2                                                   |
 |                                                                           |
 |   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_r (Word16 var1, Word16 var2)
{
    Word16 var_out;

    if (var2 > 15)
    {
        var_out = 0;
    }
    else
    {
        var_out = shr (var1, var2);

        if (var2 > 0)
        {
            if ((var1 & ((Word16) 1 << (var2 - 1))) != 0)
            {
                var_out++;
            }
        }
    }
    return (var_out);
}

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : mac_r                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Multiply var1 by var2 and shift the result left by 1. Add the 32 bit    |
 |   result to L_var3 with saturation. Round the LS 16 bits of the result    |
 |   into the MS 16 bits with saturation and shift the result right by 16.   |
 |   Return a 16 bit result.                                                 |
 |            mac_r(L_var3,var1,var2) = round(L_mac(L_var3,var1,var2))       |
 |                                                                           |
 |   Complexity weight : 2                                                   |
 |                                                                           |
 |   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 :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0x0000 8000 <= L_var_out <= 0x0000 7fff.              |
 |___________________________________________________________________________|
*/

Word16 mac_r (Word32 L_var3, Word16 var1, Word16 var2)
{
    Word16 var_out;

    L_var3 = L_mac (L_var3, var1, var2);
    L_var3 = L_add (L_var3, (Word32) 0x00008000L);
    var_out = extract_h (L_var3);
    return (var_out);
}

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : msu_r                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Multiply var1 by var2 and shift the result left by 1. Subtract the 32   |
 |   bit result to L_var3 with saturation. Round the LS 16 bits of the res-  |
 |   ult into the MS 16 bits with saturation and shift the result right by   |
 |   16. Return a 16 bit result.                                             |
 |            msu_r(L_var3,var1,var2) = round(L_msu(L_var3,var1,var2))       |
 |                                                                           |
 |   Complexity weight : 2                                                   |
 |                                                                           |
 |   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 :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0x0000 8000 <= L_var_out <= 0x0000 7fff.              |
 |___________________________________________________________________________|
*/

Word16 msu_r (Word32 L_var3, Word16 var1, Word16 var2)
{
    Word16 var_out;

    L_var3 = L_msu (L_var3, var1, var2);
    L_var3 = L_add (L_var3, (Word32) 0x00008000L);
    var_out = extract_h (L_var3);
    return (var_out);
}

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_shr_r                                                 |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Same as L_shr(L_var1,var2) but with rounding. Saturate the result in    |
 |   case of underflows or overflows :                                       |
 |    - If var2 is greater than zero :                                       |
 |          if (L_sub(L_shl(L_shr(L_var1,var2),1),L_shr(L_var1,sub(var2,1))))|
 |          is equal to zero                                                 |
 |                     then                                                  |
 |                     L_shr_r(L_var1,var2) = L_shr(L_var1,var2)             |
 |                     else                                                  |
 |                     L_shr_r(L_var1,var2) = L_add(L_shr(L_var1,var2),1)    |
 |    - If var2 is less than or equal to zero :                              |
 |                     L_shr_r(L_var1,var2) = L_shr(L_var1,var2).            |
 |                                                                           |
 |   Complexity weight : 3                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    L_var1                                                                 |
 |             32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= var1 <= 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 <= var_out <= 0x7fff ffff.                |
 |___________________________________________________________________________|
*/

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

    if (var2 > 31)
    {
        L_var_out = 0;
    }
    else
    {
        L_var_out = L_shr (L_var1, var2);
        if (var2 > 0)
        {
            if ((L_var1 & ((Word32) 1 << (var2 - 1))) != 0)
            {
                L_var_out++;
            }
        }
    }
    return (L_var_out);
}

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : L_sat                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |    32 bit L_var1 is set to 2147483647 if an overflow occured or to        |
 |    -2147483648 if an underflow occured on the most recent L_add_c,        |
 |    L_sub_c, L_macNs or L_msuNs operations. The carry and overflow values  |
 |    are binary values which can be tested and assigned values.             |
 |                                                                           |
 |   Complexity weight : 4                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    L_var1                                                                 |
 |             32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= var1 <= 0x7fff ffff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    L_var_out                                                              |
 |             32 bit long signed integer (Word32) whose value falls in the  |
 |             range : 0x8000 0000 <= var_out <= 0x7fff ffff.                |
 |___________________________________________________________________________|
*/

Word32 L_sat (Word32 L_var1)
{
    Word32 L_var_out;

    L_var_out = L_var1;

    if (Overflow)
    {
        if (Carry)
        {
            L_var_out = MIN_32;
        }
        else
        {
            L_var_out = MAX_32;
        }

        Carry = 0;
        Overflow = 0;
    }
    return (L_var_out);
}

/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : div_s                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Produces a result which is the fractional integer division of var1  by  |
 |   var2; var1 and var2 must be positive and var2 must be greater or equal  |
 |   to var1; the result is positive (leading bit equal to 0) and truncated  |
 |   to 16 bits.                                                             |
 |   If var1 = var2 then div(var1,var2) = 32767.                             |
 |                                                                           |
 |   Complexity weight : 18                                                  |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    var1                                                                   |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0x0000 0000 <= var1 <= var2 and var2 != 0.            |
 |                                                                           |
 |    var2                                                                   |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : var1 <= var2 <= 0x0000 7fff and var2 != 0.            |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0x0000 0000 <= var_out <= 0x0000 7fff.                |
 |             It's a Q15 value (point between b15 and b14).                 |
 |___________________________________________________________________________|
*/

Word16 div_s (Word16 var1, Word16 var2)
{
    Word16 var_out = 0;
    Word16 iteration;
    Word32 L_num;
    Word32 L_denom;

#if 0
    if ((var1 > var2) || (var1 < 0) || (var2 < 0))
    {
        printf ("Division Error var1=%d  var2=%d\n", var1, var2);
        exit (0);
    }
    if (var2 == 0)
    {
        printf ("Division by 0, Fatal error \n");
        exit (0);
    }
#endif

    if (var1 == 0)
    {
        var_out = 0;
    }
    else
    {
        if (var1 == var2)
        {
            var_out = MAX_16;
        }
        else
        {
            L_num = L_deposit_l (var1);
            L_denom = L_deposit_l (var2);

            for (iteration = 0; iteration < 15; iteration++)
            {
                var_out <<= 1;
                L_num <<= 1;

                if (L_num >= L_denom)
                {
                    L_num = L_sub (L_num, L_denom);
                    var_out = add (var_out, 1);
                }
            }
        }
    }

    return (var_out);
}