VM_AVXFunc.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        VM_AVXFunc.h ( VM Library, C++)
 *
 * COMMENTS:
 */

#ifndef __VM_AVXFunc__
#define __VM_AVXFunc__

#include "VM_API.h"
#include <SYS/SYS_Align.h>
#include <SYS/SYS_Types.h>

#define CPU_HAS_AVX_INSTR       1
#define VM_AVX_STYLE            1

#include <immintrin.h>
typedef __m256  v8sf;
typedef __m256i v8si;

// Plain casting (no conversion)
// MSVC has problems casting between __m128 and __m128i, so we implement a
// custom casting routine specifically for windows.

#if defined(_MSC_VER)

static SYS_FORCE_INLINE v8sf
vm_v8sf(const v8si &a)
{
    union {
        v8si ival;
        v8sf fval;
    };
    ival = a;
    return fval;
}

static SYS_FORCE_INLINE v8si
vm_v8si(const v8sf &a)
{
    union {
        v8si ival;
        v8sf fval;
    };
    fval = a;
    return ival;
}

#define V8SF(A)         vm_v8sf(A)
#define V8SI(A)         vm_v8si(A)

#else

#define V8SF(A)         (v8sf)A
#define V8SI(A)         (v8si)A

// Intrinsic missing in gcc/clang
#define _mm256_set_m128i(v0, v1)  _mm256_insertf128_si256(_mm256_castsi128_si256(v1), (v0), 1)

#endif

#define VM_SHUFFLE_MASK_AVX(a0,a1, b0,b1)       ((b1)<<6|(b0)<<4 | (a1)<<2|(a0))

template <int mask>
static SYS_FORCE_INLINE v8sf
vm_shuffle_avx(const v8sf &a, const v8sf &b)
{
    return _mm256_shuffle_ps(a, b, mask);
}

template <int mask>
static SYS_FORCE_INLINE v8si
vm_shuffle_avx(const v8si &a, const v8si &b)
{
    return V8SI(_mm256_shuffle_ps(V8SF(a), V8SF(b), mask));
}

template <int A, int B, int C, int D, typename T>
static SYS_FORCE_INLINE T
vm_shuffle_avx(const T &a, const T &b)
{
    return vm_shuffle_avx<VM_SHUFFLE_MASK_AVX(A,B,C,D)>(a, b);
}

template <int mask, typename T>
static SYS_FORCE_INLINE T
vm_shuffle_avx(const T &a)
{
    return vm_shuffle_avx<mask>(a, a);
}

template <int A, int B, int C, int D, typename T>
static SYS_FORCE_INLINE T
vm_shuffle_avx(const T &a)
{
    return vm_shuffle_avx<A,B,C,D>(a, a);
}

// The _mm256_insert_epi32 intrinsic is missing in VS2015
#if defined(_MSC_VER)
static SYS_FORCE_INLINE v8si
vm_insert_avx(const v8si v, int32 a, int n)
{
    union { v8si vector; int32 comp[8]; };
    vector = v;
    comp[n] = a;
    return vector;
}
#else
static SYS_FORCE_INLINE v8si
vm_insert_avx(const v8si v, int32 a, int n)
{
    switch(n)
    {
    case 0 : return _mm256_insert_epi32(v, a, 0);
    case 1 : return _mm256_insert_epi32(v, a, 1);
    case 2 : return _mm256_insert_epi32(v, a, 2);
    case 3 : return _mm256_insert_epi32(v, a, 3);
    case 4 : return _mm256_insert_epi32(v, a, 4);
    case 5 : return _mm256_insert_epi32(v, a, 5);
    case 6 : return _mm256_insert_epi32(v, a, 6);
    case 7 : return _mm256_insert_epi32(v, a, 7);
    }
    return v;
}
#endif

static SYS_FORCE_INLINE v8sf
vm_insert_avx(const v8sf v, float a, int n)
{
    union { v8sf vector; float comp[8]; };
    vector = v;
    comp[n] = a;
    return vector;
}

// The _mm256_extract_epi32 intrinsic is missing in VS2015
#if defined(_MSC_VER)
static SYS_FORCE_INLINE int
vm_extract_avx(const v8si v, int n)
{
    union { v8si vector; int32 comp[8]; };
    vector = v;
    return comp[n];
}
#else
static SYS_FORCE_INLINE int
vm_extract_avx(const v8si v, int n)
{
    switch(n)
    {
    case 0 : return _mm256_extract_epi32(v, 0);
    case 1 : return _mm256_extract_epi32(v, 1);
    case 2 : return _mm256_extract_epi32(v, 2);
    case 3 : return _mm256_extract_epi32(v, 3);
    case 4 : return _mm256_extract_epi32(v, 4);
    case 5 : return _mm256_extract_epi32(v, 5);
    case 6 : return _mm256_extract_epi32(v, 6);
    case 7 : return _mm256_extract_epi32(v, 7);
    }
    return 0;
}
#endif

static SYS_FORCE_INLINE float
vm_extract_avx(const v8sf v, int n)
{
    union { v8sf vector; float comp[8]; };
    vector = v;
    return comp[n];
}

static SYS_FORCE_INLINE v8sf
vm_splats_avx(float a)
{
    return _mm256_set1_ps(a);
}

static SYS_FORCE_INLINE v8si
vm_splats_avx(uint32 a)
{
    SYS_FPRealUnionF    tmp;
    tmp.uval = a;
    return V8SI(vm_splats_avx(tmp.fval));
}

static SYS_FORCE_INLINE v8si
vm_splats_avx(int32 a)
{
    return _mm256_set1_epi32(a);
}

static SYS_FORCE_INLINE v8sf
vm_splats_avx(float a0, float a1, float a2, float a3,
              float a4, float a5, float a6, float a7)
{
    return _mm256_set_ps(a7, a6, a5, a4, a3, a2, a1, a0);
}

static SYS_FORCE_INLINE v8si
vm_splats_avx(uint a0, uint a1, uint a2, uint a3,
              uint a4, uint a5, uint a6, uint a7)
{
    return _mm256_set_epi32((int32)a7, (int32)a6, (int32)a5, (int32)a4,
                            (int32)a3, (int32)a2, (int32)a1, (int32)a0);
}

static SYS_FORCE_INLINE v8si
vm_splats_avx(int32 a0, int32 a1, int32 a2, int32 a3,
              int32 a4, int32 a5, int32 a6, int32 a7)
{
    return _mm256_set_epi32(a7, a6, a5, a4, a3, a2, a1, a0);
}

static SYS_FORCE_INLINE v8si
vm_load_avx(const int32 v[8])
{
    return _mm256_loadu_si256((v8si *) v);
}

static SYS_FORCE_INLINE v8sf
vm_load_avx(const float v[8])
{
    return _mm256_loadu_ps(v);
}

static SYS_FORCE_INLINE void
vm_store_avx(int32 dst[8], v8si value)
{
    _mm256_storeu_si256((__m256i*) dst, value);
}

static SYS_FORCE_INLINE void
vm_store_avx(float dst[8], v8sf value)
{
    _mm256_storeu_ps(dst, value);
}

static SYS_FORCE_INLINE v8si
vm_izero_avx()
{
    return _mm256_setzero_si256();
}

static SYS_FORCE_INLINE v8sf
vm_zero_avx()
{
    return _mm256_setzero_ps();
}

static SYS_FORCE_INLINE v8sf
vm_negate_avx(v8sf a)
{
    return _mm256_sub_ps(_mm256_setzero_ps(), a);
}

static SYS_FORCE_INLINE v8sf
vm_abs_avx(v8sf a)
{
    return _mm256_max_ps(a, vm_negate_avx(a));
}

static SYS_FORCE_INLINE v8sf
vm_fdiv_avx(v8sf a, v8sf b)
{
    return _mm256_mul_ps(a, _mm256_rcp_ps(b));
}

static SYS_FORCE_INLINE v8sf
vm_fsqrt_avx(v8sf a)
{
    return _mm256_rcp_ps(_mm256_rsqrt_ps(a));
}

static SYS_FORCE_INLINE v8sf
vm_madd_avx(v8sf a, v8sf b, v8sf c)
{
    return _mm256_add_ps(_mm256_mul_ps(a, b), c);
}

// Some integer instructions aren't in AVX so we use SSE
#define SSE_WRAPPER_I(NAME, OP)                  \
static SYS_FORCE_INLINE v8si                             \
NAME(v8si a, v8si b)                             \
{                                                \
    __m128i la = _mm256_extractf128_si256(a, 0); \
    __m128i ua = _mm256_extractf128_si256(a, 1); \
    __m128i lb = _mm256_extractf128_si256(b, 0); \
    __m128i ub = _mm256_extractf128_si256(b, 1); \
    return _mm256_set_m128i(OP(ua, ub),          \
                            OP(la, lb));         \
}
SSE_WRAPPER_I(vm_int_cmplt_avx, _mm_cmplt_epi32)


static const v8si       theSSETrue_avx= vm_splats_avx(0xFFFFFFFF);

static SYS_FORCE_INLINE bool
vm_allbits_avx(const v8si &a)
{
    return _mm256_movemask_ps(V8SF(_mm256_cmpeq_epi32(a, theSSETrue_avx))) == 0xFF;
}


#define VM_EXTRACT_AVX  vm_extract_avx
#define VM_INSERT_AVX   vm_insert_avx
#define VM_SPLATS_AVX   vm_splats_avx
#define VM_LOAD_AVX     vm_load_avx
#define VM_STORE_AVX    vm_store_avx
#define VM_ZERO_AVX     vm_zero_avx
#define VM_IZERO_AVX    vm_izero_avx

#define VM_CMPLT_AVX(A,B)       V8SI(_mm256_cmp_ps(A,B,_CMP_LT_OQ))
#define VM_CMPLE_AVX(A,B)       V8SI(_mm256_cmp_ps(A,B,_CMP_LE_OQ))
#define VM_CMPGT_AVX(A,B)       V8SI(_mm256_cmp_ps(A,B,_CMP_GT_OQ))
#define VM_CMPGE_AVX(A,B)       V8SI(_mm256_cmp_ps(A,B,_CMP_GE_OQ))
#define VM_CMPEQ_AVX(A,B)       V8SI(_mm256_cmp_ps(A,B,_CMP_EQ_OQ))
#define VM_CMPNE_AVX(A,B)       V8SI(_mm256_cmp_ps(A,B,_CMP_NEQ_OQ))

#define VM_ICMPLT_AVX   vm_int_cmplt_avx
#define VM_ICMPGT_AVX   _mm256_cmpgt_epi32
#define VM_ICMPEQ_AVX   _mm256_cmpeq_epi32

#define VM_IADD_AVX     _mm256_add_epi32
#define VM_ISUB_AVX     _mm256_sub_epi32
#define VM_IMUL_AVX     _mm256_mullo_epi32

#define VM_ADD_AVX      _mm256_add_ps
#define VM_SUB_AVX      _mm256_sub_ps
#define VM_MUL_AVX      _mm256_mul_ps
#define VM_DIV_AVX      _mm256_div_ps
#define VM_SQRT_AVX     _mm256_sqrt_ps
#define VM_ISQRT_AVX    _mm256_rsqrt_ps
#define VM_INVERT_AVX   _mm256_rcp_ps
#define VM_ABS_AVX      vm_abs_avx

#define VM_FDIV_AVX     vm_fdiv_avx
#define VM_NEG_AVX      vm_negate_avx
#define VM_FSQRT_AVX    vm_fsqrt_avx
#define VM_MADD_AVX     vm_madd_avx

#define VM_MIN_AVX      _mm256_min_ps
#define VM_MAX_AVX      _mm256_max_ps

#define VM_AND_AVX      _mm256_and_si256
#define VM_ANDNOT_AVX   _mm256_andnot_si256
#define VM_OR_AVX       _mm256_or_si256
#define VM_XOR_AVX      _mm256_xor_si256

#define VM_ALLBITS_AVX  vm_allbits_avx

#define VM_SHUFFLE_AVX  vm_shuffle_avx

// Integer to float conversions
#define VM_SSE_ROUND_MASK_AVX   0x6000
#define VM_SSE_ROUND_ZERO_AVX   0x6000
#define VM_SSE_ROUND_UP_AVX     0x4000
#define VM_SSE_ROUND_DOWN_AVX   0x2000
#define VM_SSE_ROUND_NEAR_AVX   0x0000

#define GETROUND_AVX()  (_mm_getcsr()&VM_SSE_ROUND_MASK_AVX)
#define SETROUND_AVX(x) (_mm_setcsr(x|(_mm_getcsr()&~VM_SSE_ROUND_MASK_AVX)))

// The P functions must be invoked before FLOOR, the E functions invoked
// afterwards to reset the state.

#define VM_P_FLOOR_AVX()        uint rounding = GETROUND_AVX(); \
                                SETROUND_AVX(VM_SSE_ROUND_DOWN_AVX);
#define VM_FLOOR_AVX            _mm256_cvtps_epi32
#define VM_INT_AVX              _mm256_cvttps_epi32
#define VM_E_FLOOR_AVX()        SETROUND_AVX(rounding);

// Float to integer conversion
#define VM_IFLOAT_AVX           _mm256_cvtepi32_ps

// bitshifing  A=v8si C=int
#define VM_SHIFTLEFT_AVX(A,C)   _mm256_sll_epi32(A,_mm_setr_epi32(C,0,0,0))
#define VM_SHIFTRIGHT_AVX(A,C)  _mm256_srl_epi32(A,_mm_setr_epi32(C,0,0,0))

//
//  SSE Trig sourced from...
//  http://software-lisc.fbk.eu/avx_mathfun/avx_mathfun.h
//
static SYS_FORCE_INLINE void
vm_sincos_avx(v8sf x, v8sf *s, v8sf *c)
{

// AVX implementation of sincos
//
// Based on "sse_mathfun.h", by Julien Pommier
// http://gruntthepeon.free.fr/ssemath/
//
// Copyright (C) 2012 Giovanni Garberoglio
// Interdisciplinary Laboratory for Computational Science (LISC)
// Fondazione Bruno Kessler and University of Trento
// via Sommarive, 18
// I-38123 Trento (Italy)
//
// This software is provided 'as-is', without any express or implied
// warranty.  In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would be
//    appreciated but is not required.
// 2. Altered source versions must be plainly marked as such, and must not be
//    misrepresented as being the original software.
// 3. This notice may not be removed or altered from any source distribution.
//
// (this is the zlib license)

#define _PI32AVX_CONST(Name, Val)                               \
    static const SYS_ALIGN(32) int _pi32avx_##Name[4] =         \
        { Val, Val, Val, Val }

    _PI32AVX_CONST(1, 1);
    _PI32AVX_CONST(inv1, ~1);
    _PI32AVX_CONST(2, 2);
    _PI32AVX_CONST(4, 4);

    //declare some AVX constants -- why can't I figure a better way to do that?
#define _PS256_CONST(Name, Val)                                 \
    static const SYS_ALIGN(32) float _ps256_##Name[8] =         \
        { Val, Val, Val, Val, Val, Val, Val, Val }
#define _PS256_CONST_TYPE(Name, Type, Val)                      \
    static const SYS_ALIGN(32) Type _ps256_##Name[8] =          \
        { Val, Val, Val, Val, Val, Val, Val, Val }

    _PS256_CONST(1  , 1.0f);
    _PS256_CONST(0p5, 0.5f);

    _PS256_CONST_TYPE(sign_mask, uint32, 0x80000000);
    _PS256_CONST_TYPE(inv_sign_mask, uint32, ~0x80000000);

    _PS256_CONST(minus_cephes_DP1, -0.78515625);
    _PS256_CONST(minus_cephes_DP2, -2.4187564849853515625e-4);
    _PS256_CONST(minus_cephes_DP3, -3.77489497744594108e-8);
    _PS256_CONST(sincof_p0, -1.9515295891E-4);
    _PS256_CONST(sincof_p1,  8.3321608736E-3);
    _PS256_CONST(sincof_p2, -1.6666654611E-1);
    _PS256_CONST(coscof_p0,  2.443315711809948E-005);
    _PS256_CONST(coscof_p1, -1.388731625493765E-003);
    _PS256_CONST(coscof_p2,  4.166664568298827E-002);
    _PS256_CONST(cephes_FOPI, 1.27323954473516); // 4 / M_PI

#undef _PI32AVX_CONST
#undef _PS256_CONST
#undef _PS256_CONST_TYPE

    typedef union imm_xmm_union {
      v8si      imm;
      __m128i   xmm[2];
    } imm_xmm_union;

#define COPY_IMM_TO_XMM(imm_, xmm0_, xmm1_) {           \
        SYS_ALIGN(32) imm_xmm_union u;                  \
        u.imm = imm_;                                   \
        xmm0_ = u.xmm[0];                               \
        xmm1_ = u.xmm[1];                               \
    }

#define COPY_XMM_TO_IMM(xmm0_, xmm1_, imm_) {           \
        SYS_ALIGN(32) imm_xmm_union u;                  \
        u.xmm[0]=xmm0_; u.xmm[1]=xmm1_; imm_ = u.imm;   \
    }

    v8sf xmm1, xmm2, xmm3, sign_bit_sin, y;
    v8si imm0, imm2, imm4;

    __m128i imm0_1, imm0_2;
    __m128i imm2_1, imm2_2;
    __m128i imm4_1, imm4_2;

    sign_bit_sin = x;
    // take the absolute value
    x = _mm256_and_ps(x, *(v8sf*)_ps256_inv_sign_mask);
    // extract the sign bit (upper one)
    sign_bit_sin = _mm256_and_ps(sign_bit_sin, *(v8sf*)_ps256_sign_mask);

    // scale by 4/Pi
    y = _mm256_mul_ps(x, *(v8sf*)_ps256_cephes_FOPI);

    // we use SSE2 routines to perform the integer ops
    COPY_IMM_TO_XMM(_mm256_cvttps_epi32(y),imm2_1,imm2_2);

    imm2_1 = _mm_add_epi32(imm2_1, *(__m128i*)_pi32avx_1);
    imm2_2 = _mm_add_epi32(imm2_2, *(__m128i*)_pi32avx_1);

    imm2_1 = _mm_and_si128(imm2_1, *(__m128i*)_pi32avx_inv1);
    imm2_2 = _mm_and_si128(imm2_2, *(__m128i*)_pi32avx_inv1);

    COPY_XMM_TO_IMM(imm2_1,imm2_2,imm2);
    y = _mm256_cvtepi32_ps(imm2);

    imm4_1 = imm2_1;
    imm4_2 = imm2_2;

    imm0_1 = _mm_and_si128(imm2_1, *(__m128i*)_pi32avx_4);
    imm0_2 = _mm_and_si128(imm2_2, *(__m128i*)_pi32avx_4);

    imm0_1 = _mm_slli_epi32(imm0_1, 29);
    imm0_2 = _mm_slli_epi32(imm0_2, 29);

    COPY_XMM_TO_IMM(imm0_1, imm0_2, imm0);

    imm2_1 = _mm_and_si128(imm2_1, *(__m128i*)_pi32avx_2);
    imm2_2 = _mm_and_si128(imm2_2, *(__m128i*)_pi32avx_2);

    imm2_1 = _mm_cmpeq_epi32(imm2_1, _mm_setzero_si128());
    imm2_2 = _mm_cmpeq_epi32(imm2_2, _mm_setzero_si128());

    COPY_XMM_TO_IMM(imm2_1, imm2_2, imm2);

    v8sf swap_sign_bit_sin = _mm256_castsi256_ps(imm0);
    v8sf poly_mask = _mm256_castsi256_ps(imm2);

    // The magic pass: "Extended precision modular arithmetic"
    // x = ((x - y * DP1) - y * DP2) - y * DP3;
    xmm1 = *(v8sf*)_ps256_minus_cephes_DP1;
    xmm2 = *(v8sf*)_ps256_minus_cephes_DP2;
    xmm3 = *(v8sf*)_ps256_minus_cephes_DP3;
    xmm1 = _mm256_mul_ps(y, xmm1);
    xmm2 = _mm256_mul_ps(y, xmm2);
    xmm3 = _mm256_mul_ps(y, xmm3);
    x = _mm256_add_ps(x, xmm1);
    x = _mm256_add_ps(x, xmm2);
    x = _mm256_add_ps(x, xmm3);

    imm4_1 = _mm_sub_epi32(imm4_1, *(__m128i*)_pi32avx_2);
    imm4_2 = _mm_sub_epi32(imm4_2, *(__m128i*)_pi32avx_2);

    imm4_1 = _mm_andnot_si128(imm4_1, *(__m128i*)_pi32avx_4);
    imm4_2 = _mm_andnot_si128(imm4_2, *(__m128i*)_pi32avx_4);

    imm4_1 = _mm_slli_epi32(imm4_1, 29);
    imm4_2 = _mm_slli_epi32(imm4_2, 29);

    COPY_XMM_TO_IMM(imm4_1, imm4_2, imm4);

    v8sf sign_bit_cos = _mm256_castsi256_ps(imm4);

    sign_bit_sin = _mm256_xor_ps(sign_bit_sin, swap_sign_bit_sin);

    // Evaluate the first polynom  (0 <= x <= Pi/4)
    v8sf z = _mm256_mul_ps(x,x);
    y = *(v8sf*)_ps256_coscof_p0;

    y = _mm256_mul_ps(y, z);
    y = _mm256_add_ps(y, *(v8sf*)_ps256_coscof_p1);
    y = _mm256_mul_ps(y, z);
    y = _mm256_add_ps(y, *(v8sf*)_ps256_coscof_p2);
    y = _mm256_mul_ps(y, z);
    y = _mm256_mul_ps(y, z);
    v8sf tmp = _mm256_mul_ps(z, *(v8sf*)_ps256_0p5);
    y = _mm256_sub_ps(y, tmp);
    y = _mm256_add_ps(y, *(v8sf*)_ps256_1);

    // Evaluate the second polynom  (Pi/4 <= x <= 0)
    v8sf y2 = *(v8sf*)_ps256_sincof_p0;
    y2 = _mm256_mul_ps(y2, z);
    y2 = _mm256_add_ps(y2, *(v8sf*)_ps256_sincof_p1);
    y2 = _mm256_mul_ps(y2, z);
    y2 = _mm256_add_ps(y2, *(v8sf*)_ps256_sincof_p2);
    y2 = _mm256_mul_ps(y2, z);
    y2 = _mm256_mul_ps(y2, x);
    y2 = _mm256_add_ps(y2, x);

    // select the correct result from the two polynoms
    xmm3 = poly_mask;
    v8sf ysin2 = _mm256_and_ps(xmm3, y2);
    v8sf ysin1 = _mm256_andnot_ps(xmm3, y);
    y2 = _mm256_sub_ps(y2,ysin2);
    y = _mm256_sub_ps(y, ysin1);

    xmm1 = _mm256_add_ps(ysin1,ysin2);
    xmm2 = _mm256_add_ps(y,y2);

    // update the sign
    *s = _mm256_xor_ps(xmm1, sign_bit_sin);
    *c = _mm256_xor_ps(xmm2, sign_bit_cos);

#undef COPY_IMM_TO_XMM
#undef COPY_XMM_TO_IMM
}

static SYS_FORCE_INLINE v8sf
vm_sin_avx(v8sf x)
{
    v8sf s,c;
    vm_sincos_avx(x,&s,&c);
    return s;
}

static SYS_FORCE_INLINE v8sf
vm_cos_avx(v8sf x)
{
    v8sf s,c;
    vm_sincos_avx(x,&s,&c);
    return c;
}

static SYS_FORCE_INLINE v8sf
vm_tan_avx(v8sf x)
{
    v8sf s,c;
    vm_sincos_avx(x,&s,&c);
    return _mm256_div_ps(s,c);
}

#define VM_SINCOS_AVX   vm_sincos_avx
#define VM_SIN_AVX      vm_sin_avx
#define VM_COS_AVX      vm_cos_avx
#define VM_TAN_AVX      vm_tan_avx

#endif