ETSI basic operations

Non-Confidential

PDF version

ARM DUI0375H

ARM^® Compiler v5.06 for µVision^® armcc User Guide

Version 5

Home > Compiler-specific Features > ETSI basic operations

9.148 ETSI basic operations

The compilation tools support the original ETSI family of basic operations through intrinsics.

The original ETSI family of basic operations are described in the ETSI G.729 recommendation Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear prediction (CS-ACELP).

To make use of the ETSI basic operations in your own code, include the standard header file dspfns.h. The intrinsics supplied in dspfns.h are listed in the following table.

Table 9-15 ETSI basic operations that the ARM compilation tools support

Intrinsics
`abs_s`	`L_add_c`	`L_mult`	`L_sub_c`	`norm_l`
`add`	`L_deposit_h`	`L_negate`	`mac_r`	`round`
`div_s`	`L_deposit_l`	`L_sat`	`msu_r`	`saturate`
`extract_h`	`L_mac`	`L_shl`	`mult`	`shl`
`extract_l`	`L_macNs`	`L_shr`	`mult_r`	`shr`
`L_abs`	`L_msu`	`L_shr_r`	`negate`	`shr_r`
`L_add`	`L_msuNs`	`L_sub`	`norm_s`	`sub`

The header file dspfns.h also exposes certain status flags as global variables for use in your C or C++ programs. The status flags exposed by dspfns.h are listed in the following table.

Table 9-16 ETSI status flags exposed in the ARM compilation tools

Status flag	Description
`Overflow`	Overflow status flag. Generally, saturating functions have a sticky effect on overflow.
`Carry`	Carry status flag.

Example

#include <limits.h>
#include <stdint.h>
#include <dspfns.h>       // include ETSI basic operations
int32_t C_L_add(int32_t a, int32_t b)
{
    int32_t c = a + b;
    if (((a ^ b) & INT_MIN) == 0)
    {
        if ((c ^ a) & INT_MIN)
        {
            c = (a < 0) ? INT_MIN : INT_MAX;
        }
    }
    return c;
}
__asm int32_t asm_L_add(int32_t a, int32_t b)
{
    qadd r0, r0, r1
    bx lr
}
int32_t foo(int32_t a, int32_t b)
{
    int32_t c, d, e, f;
    Overflow = 0;         // set global overflow flag
    c = C_L_add(a, b);    // C saturating add
    d = asm_L_add(a, b);  // assembly language saturating add
    e = __qadd(a, b);     // ARM intrinsic saturating add
    f = L_add(a, b);      // ETSI saturating add
    return Overflow ? -1 : c == d == e == f; // returns 1, unless overflow
}