libdivide C++ API

The entire content of libdivide.h is wrapped inside the libdivide namespace, for clarity the libdivide namespace is omitted in the code sections below.

divider class

// This is the main divider class for use by the user (C++ API).
// The actual division algorithm is selected using the dispatcher struct
// based on the integer and algorithm template parameters.
template<typename T, Branching ALGO = BRANCHFULL>
class divider {
public:
    // Generate a libdivide divisor for d
    divider(T d);
    // Recover the original divider
    T recover() const;
    bool operator==(const divider<T, ALGO>& other) const;
    bool operator!=(const divider<T, ALGO>& other) const;
    // ...
private:
    // Storage for the actual divisor
    dispatcher<T, ALGO> div;
};

branchfree_divider

branchfree_divider is a convenience typedef which redirects to the divider class:

template <typename T>
using branchfree_divider = divider<T, BRANCHFREE>;

Operator / and /=

// Overload of operator /
template<typename T, Branching ALGO>
T operator/(T n, const divider<T, ALGO>& div);

// Overload of operator /=
template<typename T, Branching ALGO>
T& operator/=(T& n, const divider<T, ALGO>& div);

NEON vector division

// Overload of operator /
template <Branching ALGO>
uint32x4_t operator/(uint32x4_t n, const divider<uint32_t, ALGO> &div)

template <Branching ALGO>
int32x4_t operator/(int32x4_t n, const divider<int32_t, ALGO> &div)

template <Branching ALGO>
uint64x2_t operator/(uint64x2_t n, const divider<uint64_t, ALGO> &div)

template <Branching ALGO>
int64x2_t operator/(int64x2_t n, const divider<int64_t, ALGO> &div)


// Overload of operator /=
template <Branching ALGO>
uint32x4_t operator/=(uint32x4_t &n, const divider<uint32_t, ALGO> &div)

template <Branching ALGO>
int32x4_t operator/=(int32x4_t &n, const divider<int32_t, ALGO> &div)

template <Branching ALGO>
uint64x2_t operator/=(uint64x2_t &n, const divider<uint64_t, ALGO> &div);

template <Branching ALGO>
int64x2_t operator/=(int64x2_t &n, const divider<int64_t, ALGO> &div)

You need to define LIBDIVIDE_NEON to enable NEON vector division.

SVE vector division

// Overload of operator /
template <Branching ALGO>
svuint16_t operator/(svuint16_t n, const divider<uint16_t, ALGO> &div)

template <Branching ALGO>
svint16_t operator/(svint16_t n, const divider<int16_t, ALGO> &div)

template <Branching ALGO>
svuint32_t operator/(svuint32_t n, const divider<uint32_t, ALGO> &div)

template <Branching ALGO>
svint32_t operator/(svint32_t n, const divider<int32_t, ALGO> &div)

template <Branching ALGO>
svuint64_t operator/(svuint64_t n, const divider<uint64_t, ALGO> &div)

template <Branching ALGO>
svint64_t operator/(svint64_t n, const divider<int64_t, ALGO> &div)


// Overload of operator /=
template <Branching ALGO>
svuint16_t operator/=(svuint16_t &n, const divider<uint16_t, ALGO> &div)

template <Branching ALGO>
svint16_t operator/=(svint16_t &n, const divider<int16_t, ALGO> &div)

template <Branching ALGO>
svuint32_t operator/=(svuint32_t &n, const divider<uint32_t, ALGO> &div)

template <Branching ALGO>
svint32_t operator/=(svint32_t &n, const divider<int32_t, ALGO> &div)

template <Branching ALGO>
svuint64_t operator/=(svuint64_t &n, const divider<uint64_t, ALGO> &div)

template <Branching ALGO>
svint64_t operator/=(svint64_t &n, const divider<int64_t, ALGO> &div)

You need to define LIBDIVIDE_SVE and compile for a target with Arm SVE support to enable SVE vector division. LIBDIVIDE_SVE2 enables SVE2-specific instructions where libdivide can use them, and implies LIBDIVIDE_SVE.

SSE2 vector division

// Overload of operator /
template<typename T, Branching ALGO>
__m128i operator/(__m128i n, const divider<T, ALGO>& div);

// Overload of operator /=
template<typename T, Branching ALGO>
__m128i& operator/=(__m128i& n, const divider<T, ALGO>& div);

You need to define LIBDIVIDE_SSE2 to enable SSE2 vector division.

AVX2 vector division

// Overload of operator /
template<typename T, Branching ALGO>
__m256i operator/(__m256i n, const divider<T, ALGO>& div);

// Overload of operator /=
template<typename T, Branching ALGO>
__m256i& operator/=(__m256i& n, const divider<T, ALGO>& div);

You need to define LIBDIVIDE_AVX2 to enable AVX2 vector division.

AVX512 vector division

// Overload of operator /
template<typename T, Branching ALGO>
__m512i operator/(__m512i n, const divider<T, ALGO>& div);

// Overload of operator /=
template<typename T, Branching ALGO>
__m512i& operator/=(__m512i& n, const divider<T, ALGO>& div);

You need to define LIBDIVIDE_AVX512 to enable AVX512 vector division.