text: // Copyright 2009-2021 Intel Corporation
  // SPDX-License-Identifier: Apache-2.0
  
  #pragma once
  
  #include "../math/math.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 vuint<4>
    {
      ALIGNED_STRUCT_(16);
      
      typedef vboolf4 Bool;
      typedef vuint4   Int;
      typedef vfloat4 Float;
  
      enum  { size = 4 }; // number of SIMD elements
      union { __m128i v; unsigned int i[4]; }; // data
  
      ////////////////////////////////////////////////////////////////////////////////
      /// Constructors, Assignment & Cast Operators
      ////////////////////////////////////////////////////////////////////////////////
      
      __forceinline vuint() {}
      __forceinline vuint(const vuint4& a) { v = a.v; }
      __forceinline vuint4& operator =(const vuint4& a) { v = a.v; return *this; }
  
      __forceinline vuint(const __m128i a) : v(a) {}
      __forceinline operator const __m128i&() const { return v; }
      __forceinline operator       __m128i&()       { return v; }
  
  
      __forceinline vuint(unsigned int a) : v(_mm_set1_epi32(a)) {}
      __forceinline vuint(unsigned int a, unsigned int b, unsigned int c, unsigned int d) : v(_mm_set_epi32(d, c, b, a)) {}
  
  #if defined(__AVX512VL__)
      __forceinline explicit vuint(__m128 a) : v(_mm_cvtps_epu32(a)) {}
  #endif
  
  #if defined(__AVX512VL__)
      __forceinline explicit vuint(const vboolf4& a) : v(_mm_movm_epi32(a)) {}
  #else
      __forceinline explicit vuint(const vboolf4& a) : v(_mm_castps_si128((__m128)a)) {}
  #endif
  
      ////////////////////////////////////////////////////////////////////////////////
      /// Constants
      ////////////////////////////////////////////////////////////////////////////////
  
      __forceinline vuint(ZeroTy)   : v(_mm_setzero_si128()) {}
      __forceinline vuint(OneTy)    : v(_mm_set1_epi32(1)) {}
      __forceinline vuint(PosInfTy) : v(_mm_set1_epi32(unsigned(pos_inf))) {}
      __forceinline vuint(StepTy)   : v(_mm_set_epi32(3, 2, 1, 0)) {}
      __forceinline vuint(TrueTy)   { v = _mm_cmpeq_epi32(v,v); }
      __forceinline vuint(UndefinedTy) : v(_mm_castps_si128(_mm_undefined_ps())) {}
  
      ////////////////////////////////////////////////////////////////////////////////
      /// Loads and Stores
      ////////////////////////////////////////////////////////////////////////////////
  
      static __forceinline vuint4 load (const void* a) { return _mm_load_si128((__m128i*)a); }
      static __forceinline vuint4 loadu(const void* a) { return _mm_loadu_si128((__m128i*)a); }
  
      static __forceinline void store (void* ptr, const vuint4& v) { _mm_store_si128((__m128i*)ptr,v); }
      static __forceinline void storeu(void* ptr, const vuint4& v) { _mm_storeu_si128((__m128i*)ptr,v); }
      
  #if defined(__AVX512VL__)
      static __forceinline vuint4 load (const vboolf4& mask, const void* ptr) { return _mm_mask_load_epi32 (_mm_setzero_si128(),mask,ptr); }
      static __forceinline vuint4 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 vuint4& v) { _mm_mask_store_epi32 (ptr,mask,v); }
      static __forceinline void storeu(const vboolf4& mask, void* ptr, const vuint4& v) { _mm_mask_storeu_epi32(ptr,mask,v); }
  #elif defined(__AVX__)
      static __forceinline vuint4 load (const vbool4& mask, const void* a) { return _mm_castps_si128(_mm_maskload_ps((float*)a,mask)); }
      static __forceinline vuint4 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 vuint4& i) { _mm_maskstore_ps((float*)ptr,(__m128i)mask,_mm_castsi128_ps(i)); }
      static __forceinline void storeu(const vboolf4& mask, void* ptr, const vuint4& i) { _mm_maskstore_ps((float*)ptr,(__m128i)mask,_mm_castsi128_ps(i)); }
  #else
      static __forceinline vuint4 load (const vbool4& mask, const void* a) { return _mm_and_si128(_mm_load_si128 ((__m128i*)a),mask); }
      static __forceinline vuint4 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 vuint4& i) { store (ptr,select(mask,i,load (ptr))); }
      static __forceinline void storeu(const vboolf4& mask, void* ptr, const vuint4& i) { storeu(ptr,select(mask,i,loadu(ptr))); }
  #endif
  
  #if defined(__SSE4_1__)
      static __forceinline vuint4 load(const unsigned char* ptr) {
        return _mm_cvtepu8_epi32(_mm_loadl_epi64((__m128i*)ptr));
      }
  
      static __forceinline vuint4 loadu(const unsigned char* ptr) {
        return  _mm_cvtepu8_epi32(_mm_loadl_epi64((__m128i*)ptr));
      }
  
  #endif
  
      static __forceinline vuint4 load(const unsigned short* ptr) {
  #if defined (__SSE4_1__)
        return _mm_cvtepu16_epi32(_mm_loadu_si128((__m128i*)ptr));
  #else
        return vuint4(ptr[0],ptr[1],ptr[2],ptr[3]);
  #endif
      } 
  
      static __forceinline vuint4 load_nt(void* ptr) {
  #if 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 vuint4& v) {
  #if 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 vuint4 gather(const unsigned int* ptr, const vint4& index) {
  #if defined(__AVX2__)
        return _mm_i32gather_epi32((const int*)ptr, index, scale);
  #else
        return vuint4(
            *(unsigned int*)(((char*)ptr)+scale*index[0]),
            *(unsigned int*)(((char*)ptr)+scale*index[1]),
            *(unsigned int*)(((char*)ptr)+scale*index[2]),
            *(unsigned int*)(((char*)ptr)+scale*index[3]));
  #endif
      }
  
      template<int scale = 4>
      static __forceinline vuint4 gather(const vboolf4& mask, const unsigned int* ptr, const vint4& index) {
        vuint4 r = zero;
  #if defined(__AVX512VL__)
        return _mm_mmask_i32gather_epi32(r, mask, index, ptr, scale);
  #elif defined(__AVX2__)
        return _mm_mask_i32gather_epi32(r, (const int*)ptr, index, mask, scale);
  #else
        if (likely(mask[0])) r[0] = *(unsigned int*)(((char*)ptr)+scale*index[0]);
        if (likely(mask[1])) r[1] = *(unsigned int*)(((char*)ptr)+scale*index[1]);
        if (likely(mask[2])) r[2] = *(unsigned int*)(((char*)ptr)+scale*index[2]);
        if (likely(mask[3])) r[3] = *(unsigned int*)(((char*)ptr)+scale*index[3]);
        return r;
  #endif
      }
  
      ////////////////////////////////////////////////////////////////////////////////
      /// Array Access
      ////////////////////////////////////////////////////////////////////////////////
  
      __forceinline const unsigned int& operator [](size_t index) const { assert(index < 4); return i[index]; }
      __forceinline       unsigned int& operator [](size_t index)       { assert(index < 4); return i[index]; }
  
      friend __forceinline vuint4 select(const vboolf4& m, const vuint4& t, const vuint4& f) {
  #if defined(__AVX512VL__)
        return _mm_mask_blend_epi32(m, (__m128i)f, (__m128i)t);
  #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 vuint4& a) { return _mm_movepi32_mask(a); }
  #else
    __forceinline vboolf4 asBool(const vuint4& a) { return _mm_castsi128_ps(a); }
  #endif
  
    __forceinline vuint4 operator +(const vuint4& a) { return a; }
    __forceinline vuint4 operator -(const vuint4& a) { return _mm_sub_epi32(_mm_setzero_si128(), a); }
  
    ////////////////////////////////////////////////////////////////////////////////
    /// Binary Operators
    ////////////////////////////////////////////////////////////////////////////////
  
    __forceinline vuint4 operator +(const vuint4& a, const vuint4& b) { return _mm_add_epi32(a, b); }
    __forceinline vuint4 operator +(const vuint4& a, unsigned int  b) { return a + vuint4(b); }
    __forceinline vuint4 operator +(unsigned int  a, const vuint4& b) { return vuint4(a) + b; }
  
    __forceinline vuint4 operator -(const vuint4& a, const vuint4& b) { return _mm_sub_epi32(a, b); }
    __forceinline vuint4 operator -(const vuint4& a, unsigned int  b) { return a - vuint4(b); }
    __forceinline vuint4 operator -(unsigned int  a, const vuint4& b) { return vuint4(a) - b; }
  
  //#if defined(__SSE4_1__)
  //  __forceinline vuint4 operator *(const vuint4& a, const vuint4& b) { return _mm_mullo_epu32(a, b); }
  //#else
  //  __forceinline vuint4 operator *(const vuint4& a, const vuint4& b) { return vuint4(a[0]*b[0],a[1]*b[1],a[2]*b[2],a[3]*b[3]); }
  //#endif
  //  __forceinline vuint4 operator *(const vuint4& a, unsigned int  b) { return a * vuint4(b); }
  //  __forceinline vuint4 operator *(unsigned int  a, const vuint4& b) { return vuint4(a) * b; }
  
    __forceinline vuint4 operator &(const vuint4& a, const vuint4& b) { return _mm_and_si128(a, b); }
    __forceinline vuint4 operator &(const vuint4& a, unsigned int  b) { return a & vuint4(b); }
    __forceinline vuint4 operator &(unsigned int  a, const vuint4& b) { return vuint4(a) & b; }
  
    __forceinline vuint4 operator |(const vuint4& a, const vuint4& b) { return _mm_or_si128(a, b); }
    __forceinline vuint4 operator |(const vuint4& a, unsigned int  b) { return a | vuint4(b); }
    __forceinline vuint4 operator |(unsigned int  a, const vuint4& b) { return vuint4(a) | b; }
  
    __forceinline vuint4 operator ^(const vuint4& a, const vuint4& b) { return _mm_xor_si128(a, b); }
    __forceinline vuint4 operator ^(const vuint4& a, unsigned int  b) { return a ^ vuint4(b); }
    __forceinline vuint4 operator ^(unsigned int  a, const vuint4& b) { return vuint4(a) ^ b; }
  
    __forceinline vuint4 operator <<(const vuint4& a, unsigned int n) { return _mm_slli_epi32(a, n); }
    __forceinline vuint4 operator >>(const vuint4& a, unsigned int n) { return _mm_srli_epi32(a, n); }
  
    __forceinline vuint4 sll (const vuint4& a, unsigned int b) { return _mm_slli_epi32(a, b); }
    __forceinline vuint4 sra (const vuint4& a, unsigned int b) { return _mm_srai_epi32(a, b); }
    __forceinline vuint4 srl (const vuint4& a, unsigned int b) { return _mm_srli_epi32(a, b); }
    
    ////////////////////////////////////////////////////////////////////////////////
    /// Assignment Operators
    ////////////////////////////////////////////////////////////////////////////////
  
    __forceinline vuint4& operator +=(vuint4& a, const vuint4& b) { return a = a + b; }
    __forceinline vuint4& operator +=(vuint4& a, unsigned int  b) { return a = a + b; }
    
    __forceinline vuint4& operator -=(vuint4& a, const vuint4& b) { return a = a - b; }
    __forceinline vuint4& operator -=(vuint4& a, unsigned int  b) { return a = a - b; }
  
  //#if defined(__SSE4_1__)
  //  __forceinline vuint4& operator *=(vuint4& a, const vuint4& b) { return a = a * b; }
  //  __forceinline vuint4& operator *=(vuint4& a, unsigned int  b) { return a = a * b; }
  //#endif
    
    __forceinline vuint4& operator &=(vuint4& a, const vuint4& b) { return a = a & b; }
    __forceinline vuint4& operator &=(vuint4& a, unsigned int  b) { return a = a & b; }
    
    __forceinline vuint4& operator |=(vuint4& a, const vuint4& b) { return a = a | b; }
    __forceinline vuint4& operator |=(vuint4& a, unsigned int  b) { return a = a | b; }
    
    __forceinline vuint4& operator <<=(vuint4& a, unsigned int  b) { return a = a << b; }
    __forceinline vuint4& operator >>=(vuint4& a, unsigned int  b) { return a = a >> b; }
  
    ////////////////////////////////////////////////////////////////////////////////
    /// Comparison Operators + Select
    ////////////////////////////////////////////////////////////////////////////////
  
  #if defined(__AVX512VL__)
    __forceinline vboolf4 operator ==(const vuint4& a, const vuint4& b) { return _mm_cmp_epu32_mask(a,b,_MM_CMPINT_EQ); }
    __forceinline vboolf4 operator !=(const vuint4& a, const vuint4& b) { return _mm_cmp_epu32_mask(a,b,_MM_CMPINT_NE); }
    //__forceinline vboolf4 operator < (const vuint4& a, const vuint4& b) { return _mm_cmp_epu32_mask(a,b,_MM_CMPINT_LT); }
    //__forceinline vboolf4 operator >=(const vuint4& a, const vuint4& b) { return _mm_cmp_epu32_mask(a,b,_MM_CMPINT_GE); }
    //__forceinline vboolf4 operator > (const vuint4& a, const vuint4& b) { return _mm_cmp_epu32_mask(a,b,_MM_CMPINT_GT); }
    //__forceinline vboolf4 operator <=(const vuint4& a, const vuint4& b) { return _mm_cmp_epu32_mask(a,b,_MM_CMPINT_LE); }
  #else
    __forceinline vboolf4 operator ==(const vuint4& a, const vuint4& b) { return _mm_castsi128_ps(_mm_cmpeq_epi32(a, b)); }
    __forceinline vboolf4 operator !=(const vuint4& a, const vuint4& b) { return !(a == b); }
    //__forceinline vboolf4 operator < (const vuint4& a, const vuint4& b) { return _mm_castsi128_ps(_mm_cmplt_epu32(a, b)); }
    //__forceinline vboolf4 operator >=(const vuint4& a, const vuint4& b) { return !(a <  b); }
    //__forceinline vboolf4 operator > (const vuint4& a, const vuint4& b) { return _mm_castsi128_ps(_mm_cmpgt_epu32(a, b)); }
    //__forceinline vboolf4 operator <=(const vuint4& a, const vuint4& b) { return !(a >  b); }
  #endif
  
    __forceinline vboolf4 operator ==(const vuint4& a, unsigned int  b) { return a == vuint4(b); }
    __forceinline vboolf4 operator ==(unsigned int  a, const vuint4& b) { return vuint4(a) == b; }
  
    __forceinline vboolf4 operator !=(const vuint4& a, unsigned int  b) { return a != vuint4(b); }
    __forceinline vboolf4 operator !=(unsigned int  a, const vuint4& b) { return vuint4(a) != b; }
  
    //__forceinline vboolf4 operator < (const vuint4& a, unsigned int  b) { return a <  vuint4(b); }
    //__forceinline vboolf4 operator < (unsigned int  a, const vuint4& b) { return vuint4(a) <  b; }
  
    //__forceinline vboolf4 operator >=(const vuint4& a, unsigned int  b) { return a >= vuint4(b); }
    //__forceinline vboolf4 operator >=(unsigned int  a, const vuint4& b) { return vuint4(a) >= b; }
  
    //__forceinline vboolf4 operator > (const vuint4& a, unsigned int  b) { return a >  vuint4(b); }
    //__forceinline vboolf4 operator > (unsigned int  a, const vuint4& b) { return vuint4(a) >  b; }
  
    //__forceinline vboolf4 operator <=(const vuint4& a, unsigned int  b) { return a <= vuint4(b); }
    //__forceinline vboolf4 operator <=(unsigned int  a, const vuint4& b) { return vuint4(a) <= b; }
  
    __forceinline vboolf4 eq(const vuint4& a, const vuint4& b) { return a == b; }
    __forceinline vboolf4 ne(const vuint4& a, const vuint4& b) { return a != b; }
    //__forceinline vboolf4 lt(const vuint4& a, const vuint4& b) { return a <  b; }
    //__forceinline vboolf4 ge(const vuint4& a, const vuint4& b) { return a >= b; }
    //__forceinline vboolf4 gt(const vuint4& a, const vuint4& b) { return a >  b; }
    //__forceinline vboolf4 le(const vuint4& a, const vuint4& b) { return a <= b; }
  
  #if defined(__AVX512VL__)
    __forceinline vboolf4 eq(const vboolf4& mask, const vuint4& a, const vuint4& b) { return _mm_mask_cmp_epu32_mask(mask, a, b, _MM_CMPINT_EQ); }
    __forceinline vboolf4 ne(const vboolf4& mask, const vuint4& a, const vuint4& b) { return _mm_mask_cmp_epu32_mask(mask, a, b, _MM_CMPINT_NE); }
    //__forceinline vboolf4 lt(const vboolf4& mask, const vuint4& a, const vuint4& b) { return _mm_mask_cmp_epu32_mask(mask, a, b, _MM_CMPINT_LT); }
    //__forceinline vboolf4 ge(const vboolf4& mask, const vuint4& a, const vuint4& b) { return _mm_mask_cmp_epu32_mask(mask, a, b, _MM_CMPINT_GE); }
    //__forceinline vboolf4 gt(const vboolf4& mask, const vuint4& a, const vuint4& b) { return _mm_mask_cmp_epu32_mask(mask, a, b, _MM_CMPINT_GT); }
    //__forceinline vboolf4 le(const vboolf4& mask, const vuint4& a, const vuint4& b) { return _mm_mask_cmp_epu32_mask(mask, a, b, _MM_CMPINT_LE); }
  #else
    __forceinline vboolf4 eq(const vboolf4& mask, const vuint4& a, const vuint4& b) { return mask & (a == b); }
    __forceinline vboolf4 ne(const vboolf4& mask, const vuint4& a, const vuint4& b) { return mask & (a != b); }
    //__forceinline vboolf4 lt(const vboolf4& mask, const vuint4& a, const vuint4& b) { return mask & (a <  b); }
    //__forceinline vboolf4 ge(const vboolf4& mask, const vuint4& a, const vuint4& b) { return mask & (a >= b); }
    //__forceinline vboolf4 gt(const vboolf4& mask, const vuint4& a, const vuint4& b) { return mask & (a >  b); }
    //__forceinline vboolf4 le(const vboolf4& mask, const vuint4& a, const vuint4& b) { return mask & (a <= b); }
  #endif
  
    template<int mask>
    __forceinline vuint4 select(const vuint4& t, const vuint4& 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(__SSE4_1__)
    __forceinline vuint4 min(const vuint4& a, const vuint4& b) { return _mm_min_epu32(a, b); }
    __forceinline vuint4 max(const vuint4& a, const vuint4& b) { return _mm_max_epu32(a, b); }
  
  #else
    __forceinline vuint4 min(const vuint4& a, const vuint4& b) { return select(a < b,a,b); }
    __forceinline vuint4 max(const vuint4& a, const vuint4& b) { return select(a < b,b,a); }
  #endif
  
    __forceinline vuint4 min(const vuint4& a, unsigned int  b) { return min(a,vuint4(b)); }
    __forceinline vuint4 min(unsigned int  a, const vuint4& b) { return min(vuint4(a),b); }
    __forceinline vuint4 max(const vuint4& a, unsigned int  b) { return max(a,vuint4(b)); }
    __forceinline vuint4 max(unsigned int  a, const vuint4& b) { return max(vuint4(a),b); }*/
  
    ////////////////////////////////////////////////////////////////////////////////
    // Movement/Shifting/Shuffling Functions
    ////////////////////////////////////////////////////////////////////////////////
  
    __forceinline vuint4 unpacklo(const vuint4& a, const vuint4& b) { return _mm_castps_si128(_mm_unpacklo_ps(_mm_castsi128_ps(a), _mm_castsi128_ps(b))); }
    __forceinline vuint4 unpackhi(const vuint4& a, const vuint4& b) { return _mm_castps_si128(_mm_unpackhi_ps(_mm_castsi128_ps(a), _mm_castsi128_ps(b))); }
  
    template<int i0, int i1, int i2, int i3>
    __forceinline vuint4 shuffle(const vuint4& v) {
      return _mm_shuffle_epi32(v, _MM_SHUFFLE(i3, i2, i1, i0));
    }
  
    template<int i0, int i1, int i2, int i3>
    __forceinline vuint4 shuffle(const vuint4& a, const vuint4& b) {
      return _mm_castps_si128(_mm_shuffle_ps(_mm_castsi128_ps(a), _mm_castsi128_ps(b), _MM_SHUFFLE(i3, i2, i1, i0)));
    }
  
  #if defined(__SSE3__)
    template<> __forceinline vuint4 shuffle<0, 0, 2, 2>(const vuint4& v) { return _mm_castps_si128(_mm_moveldup_ps(_mm_castsi128_ps(v))); }
    template<> __forceinline vuint4 shuffle<1, 1, 3, 3>(const vuint4& v) { return _mm_castps_si128(_mm_movehdup_ps(_mm_castsi128_ps(v))); }
    template<> __forceinline vuint4 shuffle<0, 1, 0, 1>(const vuint4& v) { return _mm_castpd_si128(_mm_movedup_pd (_mm_castsi128_pd(v))); }
  #endif
  
    template<int i>
    __forceinline vuint4 shuffle(const vuint4& v) {
      return shuffle<i,i,i,i>(v);
    }
  
  #if defined(__SSE4_1__)
    template<int src> __forceinline unsigned int extract(const vuint4& b) { return _mm_extract_epi32(b, src); }
    template<int dst> __forceinline vuint4 insert(const vuint4& a, const unsigned b) { return _mm_insert_epi32(a, b, dst); }
  #else
    template<int src> __forceinline unsigned int extract(const vuint4& b) { return b[src&3]; }
    template<int dst> __forceinline vuint4 insert(const vuint4& a, const unsigned b) { vuint4 c = a; c[dst&3] = b; return c; }
  #endif
  
  
    template<> __forceinline unsigned int extract<0>(const vuint4& b) { return _mm_cvtsi128_si32(b); }
  
    __forceinline unsigned int toScalar(const vuint4& v) { return _mm_cvtsi128_si32(v); }
  
    ////////////////////////////////////////////////////////////////////////////////
    /// Reductions
    ////////////////////////////////////////////////////////////////////////////////
  
  #if 0
  #if defined(__SSE4_1__)
  
    __forceinline vuint4 vreduce_min(const vuint4& v) { vuint4 h = min(shuffle<1,0,3,2>(v),v); return min(shuffle<2,3,0,1>(h),h); }
    __forceinline vuint4 vreduce_max(const vuint4& v) { vuint4 h = max(shuffle<1,0,3,2>(v),v); return max(shuffle<2,3,0,1>(h),h); }
    __forceinline vuint4 vreduce_add(const vuint4& v) { vuint4 h = shuffle<1,0,3,2>(v)   + v ; return shuffle<2,3,0,1>(h)   + h ; }
  
    __forceinline unsigned int reduce_min(const vuint4& v) { return toScalar(vreduce_min(v)); }
    __forceinline unsigned int reduce_max(const vuint4& v) { return toScalar(vreduce_max(v)); }
    __forceinline unsigned int reduce_add(const vuint4& v) { return toScalar(vreduce_add(v)); }
  
    __forceinline size_t select_min(const vuint4& v) { return bsf(movemask(v == vreduce_min(v))); }
    __forceinline size_t select_max(const vuint4& v) { return bsf(movemask(v == vreduce_max(v))); }
  
    //__forceinline size_t select_min(const vboolf4& valid, const vuint4& v) { const vuint4 a = select(valid,v,vuint4(pos_inf)); return bsf(movemask(valid & (a == vreduce_min(a)))); }
    //__forceinline size_t select_max(const vboolf4& valid, const vuint4& v) { const vuint4 a = select(valid,v,vuint4(neg_inf)); return bsf(movemask(valid & (a == vreduce_max(a)))); }
  
  #else
  
    __forceinline unsigned int reduce_min(const vuint4& v) { return min(v[0],v[1],v[2],v[3]); }
    __forceinline unsigned int reduce_max(const vuint4& v) { return max(v[0],v[1],v[2],v[3]); }
    __forceinline unsigned int reduce_add(const vuint4& v) { return v[0]+v[1]+v[2]+v[3]; }
  
  #endif
  #endif
  
    ////////////////////////////////////////////////////////////////////////////////
    /// Output Operators
    ////////////////////////////////////////////////////////////////////////////////
  
    __forceinline embree_ostream operator <<(embree_ostream cout, const vuint4& 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
  