2 files changed, 98 insertions, 0 deletions
diff --git a/rcc/lib/CMakeLists.txt b/rcc/lib/CMakeLists.txt
index 366e6d2..6ab18c4 100644
--- a/rcc/lib/CMakeLists.txt
+++ b/rcc/lib/CMakeLists.txt
@@ -3,4 +3,5 @@
 add_rcc_library(RCCSupport
   STATIC
   Support/Errno.cc
+  Support/MathExtras.cc
 )
diff --git a/rcc/lib/Support/MathExtras.cc b/rcc/lib/Support/MathExtras.cc
new file mode 100644
index 0000000..f0db3a4
--- /dev/null
+++ b/rcc/lib/Support/MathExtras.cc
@@ -0,0 +1,97 @@
+/*
+ RCC-Project
+
+ Copyright (C) 2026 Richard Qin
+
+ This file is part of RCC-Project.
+
+ RCC-Project is free software; you can redistribute it and/or modify it under
+ the terms of the GNU General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your option) any
+ later version.
+
+ RCC-Project is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ RCC-Project; see the file COPYING.  If not see
+ <http://www.gnu.org/licenses/>.
+*/
+
+//===-- MathExtras.cpp - Implement the MathExtras header --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the MathExtras.h header
+//
+//===----------------------------------------------------------------------===//
+
+#include "rcc/Support/MathExtras.h"
+
+#ifdef _MSC_VER
+#include <limits>
+#else
+#include <cmath>
+#endif
+
+namespace rcc
+{
+
+#if defined(_MSC_VER)
+// Visual Studio defines the HUGE_VAL class of macros using purposeful
+// constant arithmetic overflow, which it then warns on when encountered.
+const float huge_valf = std::numeric_limits<float>::infinity ();
+#else
+const float huge_valf = HUGE_VALF;
+#endif
+
+/// Returns the number of digits in the given integer.
+int
+NumDigitsBase10 (uint64_t X)
+{
+  static constexpr struct ConstexprData
+  {
+    uint8_t AtLeast[65] = {};
+    uint64_t Boundaries[20] = {};
+    static constexpr int
+    NumDigitsConstexpr (uint64_t N)
+    {
+      int res = 1;
+      while (N >= 10)
+      {
+        res++;
+        N /= 10;
+      }
+      return res;
+    }
+    constexpr ConstexprData ()
+    {
+      uint64_t Val = ~0ull;
+      for (uint64_t i = 0; i <= 64; i++)
+      {
+        uint64_t Digits = NumDigitsConstexpr (Val) - 1;
+        AtLeast[i] = Digits;
+        Val >>= 1;
+      }
+      // Special case because X=0 should return 1 and not 0
+      Boundaries[0] = 0;
+      Val = 10;
+      for (uint64_t i = 1; i < 20; i++)
+      {
+        Boundaries[i] = Val;
+        Val *= 10;
+      }
+    }
+  } Data;
+
+  uint64_t Base2 = X ? std::countl_zero (X) : 64;
+  uint64_t Digits = Data.AtLeast[Base2];
+  return Digits + (X >= Data.Boundaries[Digits]);
+}
+
+} // namespace rcc