1 files changed, 125 insertions, 0 deletions
diff --git a/thirdparty/embree/kernels/common/stack_item.h b/thirdparty/embree/kernels/common/stack_item.h
new file mode 100644
index 0000000000..c31c64e862
--- /dev/null
+++ b/thirdparty/embree/kernels/common/stack_item.h
@@ -0,0 +1,125 @@
+// Copyright 2009-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "default.h"
+
+namespace embree
+{
+  /*! An item on the stack holds the node ID and distance of that node. */
+  template<typename T>
+  struct __aligned(16) StackItemT
+  {
+    /*! assert that the xchg function works */
+    static_assert(sizeof(T) <= 12, "sizeof(T) <= 12 failed");
+
+    __forceinline StackItemT() {}
+
+    __forceinline StackItemT(T &ptr, unsigned &dist) : ptr(ptr), dist(dist) {}
+
+    /*! use SSE instructions to swap stack items */
+    __forceinline static void xchg(StackItemT& a, StackItemT& b) 
+    { 
+      const vfloat4 sse_a = vfloat4::load((float*)&a); 
+      const vfloat4 sse_b = vfloat4::load((float*)&b);
+      vfloat4::store(&a,sse_b);
+      vfloat4::store(&b,sse_a);
+    }
+
+    /*! Sort 2 stack items. */
+    __forceinline friend void sort(StackItemT& s1, StackItemT& s2) {
+      if (s2.dist < s1.dist) xchg(s2,s1);
+    }
+    
+    /*! Sort 3 stack items. */
+    __forceinline friend void sort(StackItemT& s1, StackItemT& s2, StackItemT& s3)
+    {
+      if (s2.dist < s1.dist) xchg(s2,s1);
+      if (s3.dist < s2.dist) xchg(s3,s2);
+      if (s2.dist < s1.dist) xchg(s2,s1);
+    }
+    
+    /*! Sort 4 stack items. */
+    __forceinline friend void sort(StackItemT& s1, StackItemT& s2, StackItemT& s3, StackItemT& s4)
+    {
+      if (s2.dist < s1.dist) xchg(s2,s1);
+      if (s4.dist < s3.dist) xchg(s4,s3);
+      if (s3.dist < s1.dist) xchg(s3,s1);
+      if (s4.dist < s2.dist) xchg(s4,s2);
+      if (s3.dist < s2.dist) xchg(s3,s2);
+    }
+
+    /*! use SSE instructions to swap stack items */
+    __forceinline static void cmp_xchg(vint4& a, vint4& b) 
+    { 
+#if defined(__AVX512VL__)
+      const vboolf4 mask(shuffle<2,2,2,2>(b) < shuffle<2,2,2,2>(a));
+#else
+      const vboolf4 mask0(b < a);
+      const vboolf4 mask(shuffle<2,2,2,2>(mask0));
+#endif
+      const vint4 c = select(mask,b,a);
+      const vint4 d = select(mask,a,b);
+      a = c;
+      b = d;
+    }
+    
+    /*! Sort 3 stack items. */
+    __forceinline static void sort3(vint4& s1, vint4& s2, vint4& s3)
+    {
+      cmp_xchg(s2,s1);
+      cmp_xchg(s3,s2);
+      cmp_xchg(s2,s1);
+    }
+    
+    /*! Sort 4 stack items. */
+    __forceinline static void sort4(vint4& s1, vint4& s2, vint4& s3, vint4& s4)
+    {
+      cmp_xchg(s2,s1);
+      cmp_xchg(s4,s3);
+      cmp_xchg(s3,s1);
+      cmp_xchg(s4,s2);
+      cmp_xchg(s3,s2);
+    }
+
+
+    /*! Sort N stack items. */
+    __forceinline friend void sort(StackItemT* begin, StackItemT* end)
+    {
+      for (StackItemT* i = begin+1; i != end; ++i)
+      {
+        const vfloat4 item = vfloat4::load((float*)i);
+        const unsigned dist = i->dist;
+        StackItemT* j = i;
+
+        while ((j != begin) && ((j-1)->dist < dist))
+        {
+          vfloat4::store(j, vfloat4::load((float*)(j-1)));
+          --j;
+        }
+
+        vfloat4::store(j, item);
+      }
+    }
+    
+  public:
+    T ptr;
+    unsigned dist;
+  };
+
+  /*! An item on the stack holds the node ID and active ray mask. */
+  template<typename T>
+  struct __aligned(8) StackItemMaskT
+  {
+    T ptr;
+    size_t mask;
+  };
+
+  struct __aligned(8) StackItemMaskCoherent
+  {
+    size_t mask;
+    size_t parent;
+    size_t child;
+  };
+}