Fixing a bunch of alloy clang issues.

src/poly/math.cc

@@ -0,0 +1,69 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2014 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include <poly/math.h>
+
+namespace poly {
+
+// TODO(benvanik): replace with alternate implementation.
+// XMConvertFloatToHalf
+// Copyright (c) Microsoft Corporation. All rights reserved.
+uint16_t float_to_half(float value) {
+  uint32_t Result;
+  uint32_t IValue = ((uint32_t *)(&value))[0];
+  uint32_t Sign = (IValue & 0x80000000U) >> 16U;
+  IValue = IValue & 0x7FFFFFFFU;  // Hack off the sign
+  if (IValue > 0x47FFEFFFU) {
+    // The number is too large to be represented as a half. Saturate to
+    // infinity.
+    Result = 0x7FFFU;
+  } else {
+    if (IValue < 0x38800000U) {
+      // The number is too small to be represented as a normalized half.
+      // Convert it to a denormalized value.
+      uint32_t Shift = 113U - (IValue >> 23U);
+      IValue = (0x800000U | (IValue & 0x7FFFFFU)) >> Shift;
+    } else {
+      // Rebias the exponent to represent the value as a normalized half.
+      IValue += 0xC8000000U;
+    }
+    Result = ((IValue + 0x0FFFU + ((IValue >> 13U) & 1U)) >> 13U) & 0x7FFFU;
+  }
+  return (uint16_t)(Result | Sign);
+}
+
+// TODO(benvanik): replace with alternate implementation.
+// XMConvertHalfToFloat
+// Copyright (c) Microsoft Corporation. All rights reserved.
+float half_to_float(uint16_t value) {
+  uint32_t Mantissa = (uint32_t)(value & 0x03FF);
+  uint32_t Exponent;
+  if ((value & 0x7C00) != 0) {
+    // The value is normalized
+    Exponent = (uint32_t)((value >> 10) & 0x1F);
+  } else if (Mantissa != 0) {
+    // The value is denormalized
+    // Normalize the value in the resulting float
+    Exponent = 1;
+    do {
+      Exponent--;
+      Mantissa <<= 1;
+    } while ((Mantissa & 0x0400) == 0);
+    Mantissa &= 0x03FF;
+  } else {
+    // The value is zero
+    Exponent = (uint32_t)-112;
+  }
+  uint32_t Result = ((value & 0x8000) << 16) |  // Sign
+                    ((Exponent + 112) << 23) |  // Exponent
+                    (Mantissa << 13);           // Mantissa
+  return *(float *)&Result;
+}
+
+}  // namespace poly