4.11 Texas Instruments (TI) C55x intrinsics for optimizing C code

The ARM compilation tools support the emulation of selected TI C55x intrinsics.

The TI C55x compiler recognizes a number of intrinsics for the optimization of C code. The ARM compilation tools support the emulation of selected TI C55x intrinsics through the header file, c55x.h.

c55x.h gives a complete list of the TI C55x intrinsics that are emulated by the ARM compilation tools.

TI C55x intrinsics that are emulated in c55x.h include:

  • Intrinsics for addition, subtraction, negation and absolute value, such as _sadd and _ssub. For example, _sadd(v1, v2) returns the 16-bit saturated sum of v1 and v2.

  • Intrinsics for multiplication and shifting, such as _smpy and _sshl. For example, _smpy(v1, v2) returns the saturated fractional-mode product of v1 and v2.

  • Intrinsics for rounding, saturation, bitcount and extremum, such as _round and _count. For example, _round(v1) returns the value v1 rounded by adding 215 using unsaturated arithmetic, clearing the lower 16 bits.

  • Associative variants of intrinsics for addition and multiply-and-accumulate. This includes all TI C55x intrinsics prefixed with _a_, for example, _a_sadd and _a_smac.

  • Rounding variants of intrinsics for multiplication and shifting, for example, _smacr and _smasr.

The following TI C55x intrinsics are not supported in c55x.h:

  • All long long variants of intrinsics. This includes all TI C55x intrinsics prefixed with _ll, for example, _llsadd and _llshl. long long variants of intrinsics are not supported in the ARM compilation tools because they operate on 40-bit data.

  • All arithmetic intrinsics with side effects. For example, the TI C55x intrinsics _firs and _lms are not defined in c55x.h.

  • Intrinsics for ETSI support functions, such as L_add_c and L_sub_c.

    Note:

    An exception is the ETSI support function for saturating division, divs. This intrinsic is supported in c55x.h.

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