// Copyright 2009-2021 Intel Corporation
// SPDX-License-Identifier: Apache-2.0

#pragma once

#include "../math/emath.h"

#define vboolf vboolf_impl
#define vboold vboold_impl
#define vint vint_impl
#define vuint vuint_impl
#define vllong vllong_impl
#define vfloat vfloat_impl
#define vdouble vdouble_impl

namespace embree
{
  /* 4-wide SSE integer type */
  template<>
  struct vint<4>
  {
    ALIGNED_STRUCT_(16);
    
    typedef vboolf4 Bool;
    typedef vint4   Int;
    typedef vfloat4 Float;

    enum  { size = 4 };             // number of SIMD elements
    union { __m128i v; int i[4]; }; // data

    ////////////////////////////////////////////////////////////////////////////////
    /// Constructors, Assignment & Cast Operators
    ////////////////////////////////////////////////////////////////////////////////
    
    __forceinline vint() {}
    __forceinline vint(const vint4& a) { v = a.v; }
    __forceinline vint4& operator =(const vint4& a) { v = a.v; return *this; }

    __forceinline vint(__m128i a) : v(a) {}
    __forceinline operator const __m128i&() const { return v; }
    __forceinline operator       __m128i&()       { return v; }

    __forceinline vint(int a) : v(_mm_set1_epi32(a)) {}
    __forceinline vint(int a, int b, int c, int d) : v(_mm_set_epi32(d, c, b, a)) {}

    __forceinline explicit vint(__m128 a) : v(_mm_cvtps_epi32(a)) {}
#if defined(__AVX512VL__)
    __forceinline explicit vint(const vboolf4& a) : v(_mm_movm_epi32(a)) {}
#else
    __forceinline explicit vint(const vboolf4& a) : v(_mm_castps_si128((__m128)a)) {}
#endif

    __forceinline vint(long long a, long long b) : v(_mm_set_epi64x(b,a)) {}

    ////////////////////////////////////////////////////////////////////////////////
    /// Constants
    ////////////////////////////////////////////////////////////////////////////////

    __forceinline vint(ZeroTy)        : v(_mm_setzero_si128()) {}
    __forceinline vint(OneTy)         : v(_mm_set_epi32(1, 1, 1, 1)) {}
    __forceinline vint(PosInfTy)      : v(_mm_set_epi32(pos_inf, pos_inf, pos_inf, pos_inf)) {}
    __forceinline vint(NegInfTy)      : v(_mm_set_epi32(neg_inf, neg_inf, neg_inf, neg_inf)) {}
    __forceinline vint(StepTy)        : v(_mm_set_epi32(3, 2, 1, 0)) {}
    __forceinline vint(ReverseStepTy) : v(_mm_set_epi32(0, 1, 2, 3)) {}

    __forceinline vint(TrueTy)   { v = _mm_cmpeq_epi32(v,v); }
    __forceinline vint(UndefinedTy) : v(_mm_castps_si128(_mm_undefined_ps())) {}


    ////////////////////////////////////////////////////////////////////////////////
    /// Loads and Stores
    ////////////////////////////////////////////////////////////////////////////////

    static __forceinline vint4 load (const void* a) { return _mm_load_si128((__m128i*)a); }
    static __forceinline vint4 loadu(const void* a) { return _mm_loadu_si128((__m128i*)a); }

    static __forceinline void store (void* ptr, const vint4& v) { _mm_store_si128((__m128i*)ptr,v); }
    static __forceinline void storeu(void* ptr, const vint4& v) { _mm_storeu_si128((__m128i*)ptr,v); }
    
#if defined(__AVX512VL__)

    static __forceinline vint4 compact(const vboolf4& mask, vint4 &v) {
      return _mm_mask_compress_epi32(v, mask, v);
    }
    static __forceinline vint4 compact(const vboolf4& mask, vint4 &a, const vint4& b) {
      return _mm_mask_compress_epi32(a, mask, b);
    }

    static __forceinline vint4 load (const vboolf4& mask, const void* ptr) { return _mm_mask_load_epi32 (_mm_setzero_si128(),mask,ptr); }
    static __forceinline vint4 loadu(const vboolf4& mask, const void* ptr) { return _mm_mask_loadu_epi32(_mm_setzero_si128(),mask,ptr); }

    static __forceinline void store (const vboolf4& mask, void* ptr, const vint4& v) { _mm_mask_store_epi32 (ptr,mask,v); }
    static __forceinline void storeu(const vboolf4& mask, void* ptr, const vint4& v) { _mm_mask_storeu_epi32(ptr,mask,v); }
#elif defined(__AVX__)
    static __forceinline vint4 load (const vbool4& mask, const void* a) { return _mm_castps_si128(_mm_maskload_ps((float*)a,mask)); }
    static __forceinline vint4 loadu(const vbool4& mask, const void* a) { return _mm_castps_si128(_mm_maskload_ps((float*)a,mask)); }

    static __forceinline void store (const vboolf4& mask, void* ptr, const vint4& i) { _mm_maskstore_ps((float*)ptr,(__m128i)mask,_mm_castsi128_ps(i)); }
    static __forceinline void storeu(const vboolf4& mask, void* ptr, const vint4& i) { _mm_maskstore_ps((float*)ptr,(__m128i)mask,_mm_castsi128_ps(i)); }
#else
    static __forceinline vint4 load (const vbool4& mask, const void* a) { return _mm_and_si128(_mm_load_si128 ((__m128i*)a),mask); }
    static __forceinline vint4 loadu(const vbool4& mask, const void* a) { return _mm_and_si128(_mm_loadu_si128((__m128i*)a),mask); }

    static __forceinline void store (const vboolf4& mask, void* ptr, const vint4& i) { store (ptr,select(mask,i,load (ptr))); }
    static __forceinline void storeu(const vboolf4& mask, void* ptr, const vint4& i) { storeu(ptr,select(mask,i,loadu(ptr))); }
#endif


#if defined(__aarch64__)
    static __forceinline vint4 load(const unsigned char* ptr) {
        return _mm_load4epu8_epi32(((__m128i*)ptr));
    }
    static __forceinline vint4 loadu(const unsigned char* ptr) {
        return  _mm_load4epu8_epi32(((__m128i*)ptr));
    }
#elif defined(__SSE4_1__)
    static __forceinline vint4 load(const unsigned char* ptr) {
      return _mm_cvtepu8_epi32(_mm_loadl_epi64((__m128i*)ptr));
    }

    static __forceinline vint4 loadu(const unsigned char* ptr) {
      return  _mm_cvtepu8_epi32(_mm_loadl_epi64((__m128i*)ptr));
    }
#else

    static __forceinline vint4 load(const unsigned char* ptr) {
      return vint4(ptr[0],ptr[1],ptr[2],ptr[3]);
    } 

    static __forceinline vint4 loadu(const unsigned char* ptr) {
      return vint4(ptr[0],ptr[1],ptr[2],ptr[3]);
    }

#endif

    static __forceinline vint4 load(const unsigned short* ptr) {
#if defined(__aarch64__)
      return __m128i(vmovl_u16(vld1_u16(ptr)));
#elif defined (__SSE4_1__)
      return _mm_cvtepu16_epi32(_mm_loadu_si128((__m128i*)ptr));
#else
      return vint4(ptr[0],ptr[1],ptr[2],ptr[3]);
#endif
    } 

    static __forceinline void store(unsigned char* ptr, const vint4& v) {
#if defined(__aarch64__)
        int32x4_t x = v;
        uint16x4_t y = vqmovn_u32(uint32x4_t(x));
        uint8x8_t z = vqmovn_u16(vcombine_u16(y, y));
        vst1_lane_u32((uint32_t *)ptr,uint32x2_t(z), 0);
#elif defined(__SSE4_1__)
      __m128i x = v;
      x = _mm_packus_epi32(x, x);
      x = _mm_packus_epi16(x, x);
      *(int*)ptr = _mm_cvtsi128_si32(x);
#else
      for (size_t i=0;i<4;i++)
        ptr[i] = (unsigned char)v[i];
#endif
    }

    static __forceinline void store(unsigned short* ptr, const vint4& v) {
#if defined(__aarch64__)
      uint32x4_t x = uint32x4_t(v.v);
      uint16x4_t y = vqmovn_u32(x);
      vst1_u16(ptr, y);
#else
      for (size_t i=0;i<4;i++)
        ptr[i] = (unsigned short)v[i];
#endif
    }

    static __forceinline vint4 load_nt(void* ptr) {
#if defined(__aarch64__) || defined(__SSE4_1__)
      return _mm_stream_load_si128((__m128i*)ptr);
#else
      return _mm_load_si128((__m128i*)ptr); 
#endif
    }
    
    static __forceinline void store_nt(void* ptr, const vint4& v) {
#if !defined(__aarch64__) && defined(__SSE4_1__)
      _mm_stream_ps((float*)ptr, _mm_castsi128_ps(v));
#else
      _mm_store_si128((__m128i*)ptr,v);
#endif
    }

    template<int scale = 4>
    static __forceinline vint4 gather(const int* ptr, const vint4& index) {
#if defined(__AVX2__) && !defined(__aarch64__)
      return _mm_i32gather_epi32(ptr, index, scale);
#else
      return vint4(
          *(int*)(((char*)ptr)+scale*index[0]),
          *(int*)(((char*)ptr)+scale*index[1]),
          *(int*)(((char*)ptr)+scale*index[2]),
          *(int*)(((char*)ptr)+scale*index[3]));
#endif
    }

    template<int scale = 4>
    static __forceinline vint4 gather(const vboolf4& mask, const int* ptr, const vint4& index) {
      vint4 r = zero;
#if defined(__AVX512VL__)
      return _mm_mmask_i32gather_epi32(r, mask, index, ptr, scale);
#elif defined(__AVX2__) && !defined(__aarch64__)
      return _mm_mask_i32gather_epi32(r, ptr, index, mask, scale);
#else
      if (likely(mask[0])) r[0] = *(int*)(((char*)ptr)+scale*index[0]);
      if (likely(mask[1])) r[1] = *(int*)(((char*)ptr)+scale*index[1]);
      if (likely(mask[2])) r[2] = *(int*)(((char*)ptr)+scale*index[2]);
      if (likely(mask[3])) r[3] = *(int*)(((char*)ptr)+scale*index[3]);
      return r;
#endif
    }

    template<int scale = 4>
    static __forceinline void scatter(void* ptr, const vint4& index, const vint4& v)
    {
#if defined(__AVX512VL__)
      _mm_i32scatter_epi32((int*)ptr, index, v, scale);
#else
      *(int*)(((char*)ptr)+scale*index[0]) = v[0];
      *(int*)(((char*)ptr)+scale*index[1]) = v[1];
      *(int*)(((char*)ptr)+scale*index[2]) = v[2];
      *(int*)(((char*)ptr)+scale*index[3]) = v[3];
#endif
    }

    template<int scale = 4>
    static __forceinline void scatter(const vboolf4& mask, void* ptr, const vint4& index, const vint4& v)
    {
#if defined(__AVX512VL__)
      _mm_mask_i32scatter_epi32((int*)ptr, mask, index, v, scale);
#else
      if (likely(mask[0])) *(int*)(((char*)ptr)+scale*index[0]) = v[0];
      if (likely(mask[1])) *(int*)(((char*)ptr)+scale*index[1]) = v[1];
      if (likely(mask[2])) *(int*)(((char*)ptr)+scale*index[2]) = v[2];
      if (likely(mask[3])) *(int*)(((char*)ptr)+scale*index[3]) = v[3];
#endif
    }

#if defined(__x86_64__) || defined(__aarch64__)
    static __forceinline vint4 broadcast64(long long a) { return _mm_set1_epi64x(a); }
#endif

    ////////////////////////////////////////////////////////////////////////////////
    /// Array Access
    ////////////////////////////////////////////////////////////////////////////////

    __forceinline const int& operator [](size_t index) const { assert(index < 4); return i[index]; }
    __forceinline       int& operator [](size_t index)       { assert(index < 4); return i[index]; }

    friend __forceinline vint4 select(const vboolf4& m, const vint4& t, const vint4& f) {
#if defined(__AVX512VL__)
      return _mm_mask_blend_epi32(m, (__m128i)f, (__m128i)t);
#elif defined(__aarch64__)
      return _mm_castps_si128(_mm_blendv_ps((__m128)f.v,(__m128) t.v, (__m128)m.v));
#elif defined(__SSE4_1__)
      return _mm_castps_si128(_mm_blendv_ps(_mm_castsi128_ps(f), _mm_castsi128_ps(t), m)); 
#else
      return _mm_or_si128(_mm_and_si128(m, t), _mm_andnot_si128(m, f)); 
#endif
    }
  };

  ////////////////////////////////////////////////////////////////////////////////
  /// Unary Operators
  ////////////////////////////////////////////////////////////////////////////////

#if defined(__AVX512VL__)
  __forceinline vboolf4 asBool(const vint4& a) { return _mm_movepi32_mask(a); }
#else
  __forceinline vboolf4 asBool(const vint4& a) { return _mm_castsi128_ps(a); }
#endif

  __forceinline vint4 operator +(const vint4& a) { return a; }
  __forceinline vint4 operator -(const vint4& a) { return _mm_sub_epi32(_mm_setzero_si128(), a); }
#if defined(__aarch64__)
  __forceinline vint4 abs(const vint4& a) { return vabsq_s32(a.v); }
#elif defined(__SSSE3__)
  __forceinline vint4 abs(const vint4& a) { return _mm_abs_epi32(a); }
#endif

  ////////////////////////////////////////////////////////////////////////////////
  /// Binary Operators
  ////////////////////////////////////////////////////////////////////////////////

  __forceinline vint4 operator +(const vint4& a, const vint4& b) { return _mm_add_epi32(a, b); }
  __forceinline vint4 operator +(const vint4& a, int          b) { return a + vint4(b); }
  __forceinline vint4 operator +(int          a, const vint4& b) { return vint4(a) + b; }

  __forceinline vint4 operator -(const vint4& a, const vint4& b) { return _mm_sub_epi32(a, b); }
  __forceinline vint4 operator -(const vint4& a, int          b) { return a - vint4(b); }
  __forceinline vint4 operator -(int          a, const vint4& b) { return vint4(a) - b; }

#if (defined(__aarch64__)) || defined(__SSE4_1__)
  __forceinline vint4 operator *(const vint4& a, const vint4& b) { return _mm_mullo_epi32(a, b); }
#else
  __forceinline vint4 operator *(const vint4& a, const vint4& b) { return vint4(a[0]*b[0],a[1]*b[1],a[2]*b[2],a[3]*b[3]); }
#endif
  __forceinline vint4 operator *(const vint4& a, int          b) { return a * vint4(b); }
  __forceinline vint4 operator *(int          a, const vint4& b) { return vint4(a) * b; }

  __forceinline vint4 operator &(const vint4& a, const vint4& b) { return _mm_and_si128(a, b); }
  __forceinline vint4 operator &(const vint4& a, int          b) { return a & vint4(b); }
  __forceinline vint4 operator &(int          a, const vint4& b) { return vint4(a) & b; }

  __forceinline vint4 operator |(const vint4& a, const vint4& b) { return _mm_or_si128(a, b); }
  __forceinline vint4 operator |(const vint4& a, int          b) { return a | vint4(b); }
  __forceinline vint4 operator |(int          a, const vint4& b) { return vint4(a) | b; }

  __forceinline vint4 operator ^(const vint4& a, const vint4& b) { return _mm_xor_si128(a, b); }
  __forceinline vint4 operator ^(const vint4& a, int          b) { return a ^ vint4(b); }
  __forceinline vint4 operator ^(int          a, const vint4& b) { return vint4(a) ^ b; }

  __forceinline vint4 operator <<(const vint4& a, const int n) { return _mm_slli_epi32(a, n); }
  __forceinline vint4 operator >>(const vint4& a, const int n) { return _mm_srai_epi32(a, n); }

  __forceinline vint4 sll (const vint4& a, int b) { return _mm_slli_epi32(a, b); }
  __forceinline vint4 sra (const vint4& a, int b) { return _mm_srai_epi32(a, b); }
  __forceinline vint4 srl (const vint4& a, int b) { return _mm_srli_epi32(a, b); }
  
  ////////////////////////////////////////////////////////////////////////////////
  /// Assignment Operators
  ////////////////////////////////////////////////////////////////////////////////

  __forceinline vint4& operator +=(vint4& a, const vint4& b) { return a = a + b; }
  __forceinline vint4& operator +=(vint4& a, int          b) { return a = a + b; }
  
  __forceinline vint4& operator -=(vint4& a, const vint4& b) { return a = a - b; }
  __forceinline vint4& operator -=(vint4& a, int          b) { return a = a - b; }

#if (defined(__aarch64__)) || defined(__SSE4_1__)
  __forceinline vint4& operator *=(vint4& a, const vint4& b) { return a = a * b; }
  __forceinline vint4& operator *=(vint4& a, int          b) { return a = a * b; }
#endif
  
  __forceinline vint4& operator &=(vint4& a, const vint4& b) { return a = a & b; }
  __forceinline vint4& operator &=(vint4& a, int          b) { return a = a & b; }
  
  __forceinline vint4& operator |=(vint4& a, const vint4& b) { return a = a | b; }
  __forceinline vint4& operator |=(vint4& a, int          b) { return a = a | b; }
  
  __forceinline vint4& operator <<=(vint4& a, int b) { return a = a << b; }
  __forceinline vint4& operator >>=(vint4& a, int b) { return a = a >> b; }

  ////////////////////////////////////////////////////////////////////////////////
  /// Comparison Operators + Select
  ////////////////////////////////////////////////////////////////////////////////

#if defined(__AVX512VL__)
  __forceinline vboolf4 operator ==(const vint4& a, const vint4& b) { return _mm_cmp_epi32_mask(a,b,_MM_CMPINT_EQ); }
  __forceinline vboolf4 operator !=(const vint4& a, const vint4& b) { return _mm_cmp_epi32_mask(a,b,_MM_CMPINT_NE); }
  __forceinline vboolf4 operator < (const vint4& a, const vint4& b) { return _mm_cmp_epi32_mask(a,b,_MM_CMPINT_LT); }
  __forceinline vboolf4 operator >=(const vint4& a, const vint4& b) { return _mm_cmp_epi32_mask(a,b,_MM_CMPINT_GE); }
  __forceinline vboolf4 operator > (const vint4& a, const vint4& b) { return _mm_cmp_epi32_mask(a,b,_MM_CMPINT_GT); }
  __forceinline vboolf4 operator <=(const vint4& a, const vint4& b) { return _mm_cmp_epi32_mask(a,b,_MM_CMPINT_LE); }
#else
  __forceinline vboolf4 operator ==(const vint4& a, const vint4& b) { return _mm_castsi128_ps(_mm_cmpeq_epi32(a, b)); }
  __forceinline vboolf4 operator !=(const vint4& a, const vint4& b) { return !(a == b); }
  __forceinline vboolf4 operator < (const vint4& a, const vint4& b) { return _mm_castsi128_ps(_mm_cmplt_epi32(a, b)); }
  __forceinline vboolf4 operator >=(const vint4& a, const vint4& b) { return !(a <  b); }
  __forceinline vboolf4 operator > (const vint4& a, const vint4& b) { return _mm_castsi128_ps(_mm_cmpgt_epi32(a, b)); }
  __forceinline vboolf4 operator <=(const vint4& a, const vint4& b) { return !(a >  b); }
#endif

  __forceinline vboolf4 operator ==(const vint4& a, int          b) { return a == vint4(b); }
  __forceinline vboolf4 operator ==(int          a, const vint4& b) { return vint4(a) == b; }

  __forceinline vboolf4 operator !=(const vint4& a, int          b) { return a != vint4(b); }
  __forceinline vboolf4 operator !=(int          a, const vint4& b) { return vint4(a) != b; }

  __forceinline vboolf4 operator < (const vint4& a, int          b) { return a <  vint4(b); }
  __forceinline vboolf4 operator < (int          a, const vint4& b) { return vint4(a) <  b; }

  __forceinline vboolf4 operator >=(const vint4& a, int          b) { return a >= vint4(b); }
  __forceinline vboolf4 operator >=(int          a, const vint4& b) { return vint4(a) >= b; }

  __forceinline vboolf4 operator > (const vint4& a, int          b) { return a >  vint4(b); }
  __forceinline vboolf4 operator > (int          a, const vint4& b) { return vint4(a) >  b; }

  __forceinline vboolf4 operator <=(const vint4& a, int          b) { return a <= vint4(b); }
  __forceinline vboolf4 operator <=(int          a, const vint4& b) { return vint4(a) <= b; }

  __forceinline vboolf4 eq(const vint4& a, const vint4& b) { return a == b; }
  __forceinline vboolf4 ne(const vint4& a, const vint4& b) { return a != b; }
  __forceinline vboolf4 lt(const vint4& a, const vint4& b) { return a <  b; }
  __forceinline vboolf4 ge(const vint4& a, const vint4& b) { return a >= b; }
  __forceinline vboolf4 gt(const vint4& a, const vint4& b) { return a >  b; }
  __forceinline vboolf4 le(const vint4& a, const vint4& b) { return a <= b; }

#if defined(__AVX512VL__)
  __forceinline vboolf4 eq(const vboolf4& mask, const vint4& a, const vint4& b) { return _mm_mask_cmp_epi32_mask(mask, a, b, _MM_CMPINT_EQ); }
  __forceinline vboolf4 ne(const vboolf4& mask, const vint4& a, const vint4& b) { return _mm_mask_cmp_epi32_mask(mask, a, b, _MM_CMPINT_NE); }
  __forceinline vboolf4 lt(const vboolf4& mask, const vint4& a, const vint4& b) { return _mm_mask_cmp_epi32_mask(mask, a, b, _MM_CMPINT_LT); }
  __forceinline vboolf4 ge(const vboolf4& mask, const vint4& a, const vint4& b) { return _mm_mask_cmp_epi32_mask(mask, a, b, _MM_CMPINT_GE); }
  __forceinline vboolf4 gt(const vboolf4& mask, const vint4& a, const vint4& b) { return _mm_mask_cmp_epi32_mask(mask, a, b, _MM_CMPINT_GT); }
  __forceinline vboolf4 le(const vboolf4& mask, const vint4& a, const vint4& b) { return _mm_mask_cmp_epi32_mask(mask, a, b, _MM_CMPINT_LE); }
#else
  __forceinline vboolf4 eq(const vboolf4& mask, const vint4& a, const vint4& b) { return mask & (a == b); }
  __forceinline vboolf4 ne(const vboolf4& mask, const vint4& a, const vint4& b) { return mask & (a != b); }
  __forceinline vboolf4 lt(const vboolf4& mask, const vint4& a, const vint4& b) { return mask & (a <  b); }
  __forceinline vboolf4 ge(const vboolf4& mask, const vint4& a, const vint4& b) { return mask & (a >= b); }
  __forceinline vboolf4 gt(const vboolf4& mask, const vint4& a, const vint4& b) { return mask & (a >  b); }
  __forceinline vboolf4 le(const vboolf4& mask, const vint4& a, const vint4& b) { return mask & (a <= b); }
#endif

  template<int mask>
  __forceinline vint4 select(const vint4& t, const vint4& f) {
#if defined(__SSE4_1__) 
    return _mm_castps_si128(_mm_blend_ps(_mm_castsi128_ps(f), _mm_castsi128_ps(t), mask));
#else
    return select(vboolf4(mask), t, f);
#endif    
  }

#if defined(__aarch64__) || defined(__SSE4_1__)
  __forceinline vint4 min(const vint4& a, const vint4& b) { return _mm_min_epi32(a, b); }
  __forceinline vint4 max(const vint4& a, const vint4& b) { return _mm_max_epi32(a, b); }

  __forceinline vint4 umin(const vint4& a, const vint4& b) { return _mm_min_epu32(a, b); }
  __forceinline vint4 umax(const vint4& a, const vint4& b) { return _mm_max_epu32(a, b); }

#else
  __forceinline vint4 min(const vint4& a, const vint4& b) { return select(a < b,a,b); }
  __forceinline vint4 max(const vint4& a, const vint4& b) { return select(a < b,b,a); }
#endif

  __forceinline vint4 min(const vint4& a, int          b) { return min(a,vint4(b)); }
  __forceinline vint4 min(int          a, const vint4& b) { return min(vint4(a),b); }
  __forceinline vint4 max(const vint4& a, int          b) { return max(a,vint4(b)); }
  __forceinline vint4 max(int          a, const vint4& b) { return max(vint4(a),b); }

  ////////////////////////////////////////////////////////////////////////////////
  // Movement/Shifting/Shuffling Functions
  ////////////////////////////////////////////////////////////////////////////////

  __forceinline vint4 unpacklo(const vint4& a, const vint4& b) { return _mm_castps_si128(_mm_unpacklo_ps(_mm_castsi128_ps(a), _mm_castsi128_ps(b))); }
  __forceinline vint4 unpackhi(const vint4& a, const vint4& b) { return _mm_castps_si128(_mm_unpackhi_ps(_mm_castsi128_ps(a), _mm_castsi128_ps(b))); }

#if defined(__aarch64__)
    template<int i0, int i1, int i2, int i3>
    __forceinline vint4 shuffle(const vint4& v) {
        return vreinterpretq_s32_u8(vqtbl1q_u8( (uint8x16_t)v.v, _MN_SHUFFLE(i0, i1, i2, i3)));
    }
    template<int i0, int i1, int i2, int i3>
    __forceinline vint4 shuffle(const vint4& a, const vint4& b) {
        return vreinterpretq_s32_u8(vqtbl2q_u8( (uint8x16x2_t){(uint8x16_t)a.v, (uint8x16_t)b.v}, _MF_SHUFFLE(i0, i1, i2, i3)));
    }
#else
  template<int i0, int i1, int i2, int i3>
  __forceinline vint4 shuffle(const vint4& v) {
    return _mm_shuffle_epi32(v, _MM_SHUFFLE(i3, i2, i1, i0));
  }

  template<int i0, int i1, int i2, int i3>
  __forceinline vint4 shuffle(const vint4& a, const vint4& b) {
    return _mm_castps_si128(_mm_shuffle_ps(_mm_castsi128_ps(a), _mm_castsi128_ps(b), _MM_SHUFFLE(i3, i2, i1, i0)));
  }
#endif
#if defined(__SSE3__)
  template<> __forceinline vint4 shuffle<0, 0, 2, 2>(const vint4& v) { return _mm_castps_si128(_mm_moveldup_ps(_mm_castsi128_ps(v))); }
  template<> __forceinline vint4 shuffle<1, 1, 3, 3>(const vint4& v) { return _mm_castps_si128(_mm_movehdup_ps(_mm_castsi128_ps(v))); }
  template<> __forceinline vint4 shuffle<0, 1, 0, 1>(const vint4& v) { return _mm_castpd_si128(_mm_movedup_pd (_mm_castsi128_pd(v))); }
#endif

  template<int i>
  __forceinline vint4 shuffle(const vint4& v) {
    return shuffle<i,i,i,i>(v);
  }

#if defined(__SSE4_1__) && !defined(__aarch64__)
  template<int src> __forceinline int extract(const vint4& b) { return _mm_extract_epi32(b, src); }
  template<int dst> __forceinline vint4 insert(const vint4& a, const int b) { return _mm_insert_epi32(a, b, dst); }
#else
  template<int src> __forceinline int extract(const vint4& b) { return b[src&3]; }
  template<int dst> __forceinline vint4 insert(const vint4& a, int b) { vint4 c = a; c[dst&3] = b; return c; }
#endif

  template<> __forceinline int extract<0>(const vint4& b) { return _mm_cvtsi128_si32(b); }
  
  __forceinline int toScalar(const vint4& v) { return _mm_cvtsi128_si32(v); }
  
#if defined(__aarch64__)
  __forceinline size_t toSizeT(const vint4& v) {
    uint64x2_t x = uint64x2_t(v.v);
    return x[0];
  }
#else
__forceinline size_t toSizeT(const vint4& v) { 
#if defined(__WIN32__) && !defined(__X86_64__) // win32 workaround
    return toScalar(v);
#elif defined(__ARM_NEON)
    // FIXME(LTE): Do we need a swap(i.e. use lane 1)?
    return vgetq_lane_u64(*(reinterpret_cast<const uint64x2_t *>(&v)), 0);
#else
    return _mm_cvtsi128_si64(v); 
#endif
  }
#endif

#if defined(__AVX512VL__)

  __forceinline vint4 permute(const vint4 &a, const vint4 &index) {
    return  _mm_castps_si128(_mm_permutevar_ps(_mm_castsi128_ps(a),index));
  }

  template<int i>
  __forceinline vint4 align_shift_right(const vint4& a, const vint4& b) {
    return _mm_alignr_epi32(a, b, i);    
  }  
#endif

  ////////////////////////////////////////////////////////////////////////////////
  /// Reductions
  ////////////////////////////////////////////////////////////////////////////////

#if defined(__aarch64__) || defined(__SSE4_1__)

#if defined(__aarch64__)
    __forceinline vint4 vreduce_min(const vint4& v) { int h = vminvq_s32(v); return vdupq_n_s32(h); }
    __forceinline vint4 vreduce_max(const vint4& v) { int h = vmaxvq_s32(v); return vdupq_n_s32(h); }
    __forceinline vint4 vreduce_add(const vint4& v) { int h = vaddvq_s32(v); return vdupq_n_s32(h); }

    __forceinline int reduce_min(const vint4& v) { return vminvq_s32(v); }
    __forceinline int reduce_max(const vint4& v) { return vmaxvq_s32(v); }
    __forceinline int reduce_add(const vint4& v) { return vaddvq_s32(v); }
#else
  __forceinline vint4 vreduce_min(const vint4& v) { vint4 h = min(shuffle<1,0,3,2>(v),v); return min(shuffle<2,3,0,1>(h),h); }
  __forceinline vint4 vreduce_max(const vint4& v) { vint4 h = max(shuffle<1,0,3,2>(v),v); return max(shuffle<2,3,0,1>(h),h); }
  __forceinline vint4 vreduce_add(const vint4& v) { vint4 h = shuffle<1,0,3,2>(v)   + v ; return shuffle<2,3,0,1>(h)   + h ; }

  __forceinline int reduce_min(const vint4& v) { return toScalar(vreduce_min(v)); }
  __forceinline int reduce_max(const vint4& v) { return toScalar(vreduce_max(v)); }
  __forceinline int reduce_add(const vint4& v) { return toScalar(vreduce_add(v)); }
#endif

  __forceinline size_t select_min(const vint4& v) { return bsf(movemask(v == vreduce_min(v))); }
  __forceinline size_t select_max(const vint4& v) { return bsf(movemask(v == vreduce_max(v))); }

  __forceinline size_t select_min(const vboolf4& valid, const vint4& v) { const vint4 a = select(valid,v,vint4(pos_inf)); return bsf(movemask(valid & (a == vreduce_min(a)))); }
  __forceinline size_t select_max(const vboolf4& valid, const vint4& v) { const vint4 a = select(valid,v,vint4(neg_inf)); return bsf(movemask(valid & (a == vreduce_max(a)))); }

#else

  __forceinline int reduce_min(const vint4& v) { return min(v[0],v[1],v[2],v[3]); }
  __forceinline int reduce_max(const vint4& v) { return max(v[0],v[1],v[2],v[3]); }
  __forceinline int reduce_add(const vint4& v) { return v[0]+v[1]+v[2]+v[3]; }

#endif

  ////////////////////////////////////////////////////////////////////////////////
  /// Sorting networks
  ////////////////////////////////////////////////////////////////////////////////

#if (defined(__aarch64__)) || defined(__SSE4_1__)

  __forceinline vint4 usort_ascending(const vint4& v)
  {
    const vint4 a0 = v;
    const vint4 b0 = shuffle<1,0,3,2>(a0);
    const vint4 c0 = umin(a0,b0);
    const vint4 d0 = umax(a0,b0);
    const vint4 a1 = select<0x5 /* 0b0101 */>(c0,d0);
    const vint4 b1 = shuffle<2,3,0,1>(a1);
    const vint4 c1 = umin(a1,b1);
    const vint4 d1 = umax(a1,b1);
    const vint4 a2 = select<0x3 /* 0b0011 */>(c1,d1);
    const vint4 b2 = shuffle<0,2,1,3>(a2);
    const vint4 c2 = umin(a2,b2);
    const vint4 d2 = umax(a2,b2);
    const vint4 a3 = select<0x2 /* 0b0010 */>(c2,d2);
    return a3;
  }

  __forceinline vint4 usort_descending(const vint4& v)
  {
    const vint4 a0 = v;
    const vint4 b0 = shuffle<1,0,3,2>(a0);
    const vint4 c0 = umax(a0,b0);
    const vint4 d0 = umin(a0,b0);
    const vint4 a1 = select<0x5 /* 0b0101 */>(c0,d0);
    const vint4 b1 = shuffle<2,3,0,1>(a1);
    const vint4 c1 = umax(a1,b1);
    const vint4 d1 = umin(a1,b1);
    const vint4 a2 = select<0x3 /* 0b0011 */>(c1,d1);
    const vint4 b2 = shuffle<0,2,1,3>(a2);
    const vint4 c2 = umax(a2,b2);
    const vint4 d2 = umin(a2,b2);
    const vint4 a3 = select<0x2 /* 0b0010 */>(c2,d2);
    return a3;
  }

#else

  __forceinline vint4 usort_ascending(const vint4& v)
  {
    const vint4 a0 = v-vint4(0x80000000);
    const vint4 b0 = shuffle<1,0,3,2>(a0);
    const vint4 c0 = min(a0,b0);
    const vint4 d0 = max(a0,b0);
    const vint4 a1 = select<0x5 /* 0b0101 */>(c0,d0);
    const vint4 b1 = shuffle<2,3,0,1>(a1);
    const vint4 c1 = min(a1,b1);
    const vint4 d1 = max(a1,b1);
    const vint4 a2 = select<0x3 /* 0b0011 */>(c1,d1);
    const vint4 b2 = shuffle<0,2,1,3>(a2);
    const vint4 c2 = min(a2,b2);
    const vint4 d2 = max(a2,b2);
    const vint4 a3 = select<0x2 /* 0b0010 */>(c2,d2);
    return a3+vint4(0x80000000);
  }

  __forceinline vint4 usort_descending(const vint4& v)
  {
    const vint4 a0 = v-vint4(0x80000000);
    const vint4 b0 = shuffle<1,0,3,2>(a0);
    const vint4 c0 = max(a0,b0);
    const vint4 d0 = min(a0,b0);
    const vint4 a1 = select<0x5 /* 0b0101 */>(c0,d0);
    const vint4 b1 = shuffle<2,3,0,1>(a1);
    const vint4 c1 = max(a1,b1);
    const vint4 d1 = min(a1,b1);
    const vint4 a2 = select<0x3 /* 0b0011 */>(c1,d1);
    const vint4 b2 = shuffle<0,2,1,3>(a2);
    const vint4 c2 = max(a2,b2);
    const vint4 d2 = min(a2,b2);
    const vint4 a3 = select<0x2 /* 0b0010 */>(c2,d2);
    return a3+vint4(0x80000000);
  }

#endif

  ////////////////////////////////////////////////////////////////////////////////
  /// Output Operators
  ////////////////////////////////////////////////////////////////////////////////

  __forceinline embree_ostream operator <<(embree_ostream cout, const vint4& a) {
    return cout << "<" << a[0] << ", " << a[1] << ", " << a[2] << ", " << a[3] << ">";
  }
}

#undef vboolf
#undef vboold
#undef vint
#undef vuint
#undef vllong
#undef vfloat
#undef vdouble