chore: import upstream snapshot with attribution

2026-07-13 13:35:51 +08:00
commit c36a561cd8
2172 changed files with 455595 additions and 0 deletions
@@ -0,0 +1,68 @@
+/**
+ *  Copyright (c) 2023 by Contributors
+ * @file dgl/runtime/ndarray.h
+ * @brief BFloat16 CPU header
+ */
+#ifndef DGL_RUNTIME_BFLOAT16_H_
+#define DGL_RUNTIME_BFLOAT16_H_
+
+#include <cmath>
+
+class BFloat16 {
+  uint16_t val;
+
+ public:
+  constexpr BFloat16() : val(0) {}
+  // Disable lint "explicit" warning, since implicit usage on constructor is
+  // expected.
+  BFloat16(float f) {  // NOLINT
+    if (std::isnan(f)) {
+      val = 0x7FC0;
+    } else {
+      union {
+        uint16_t iraw16[2];
+        uint32_t iraw32;
+        float f32;
+      };
+
+      f32 = f;
+      const uint32_t rounding_bias = 0x00007FFF + (iraw16[1] & 0x1);
+      val = static_cast<uint16_t>((iraw32 + rounding_bias) >> 16);
+    }
+  }
+  static constexpr BFloat16 Min() {
+    BFloat16 min;
+    min.val = 0xFF80;
+    return min;
+  }
+
+  static constexpr BFloat16 Max() {
+    BFloat16 max;
+    max.val = 0x7F80;
+    return max;
+  }
+
+  BFloat16& operator-=(const float& rhs) {
+    float lhs = (*this);
+    (*this) = lhs - rhs;
+    return *this;
+  }
+
+  BFloat16& operator+=(const float& rhs) {
+    float lhs = (*this);
+    (*this) = lhs + rhs;
+    return *this;
+  }
+
+  operator float() const {
+    union {
+      float f;
+      uint16_t raw[2];
+    };
+    raw[0] = 0;
+    raw[1] = val;
+    return f;
+  }
+};
+
+#endif  // DGL_RUNTIME_BFLOAT16_H_