[MIPS] Initial checkin for MIPS changes for GOLD.

gold/utils.h

+// utils.h -- utilities for manipulating integers of up to 32-bits.
+
+// Copyright 2011 Free Software Foundation, Inc.
+// Written by Aleksandar Simeonov <aleksandar.simeonov@rt-rk.com>
+// based on the ARM code written by Doug Kwan <dougkwan@google.com>
+
+// This file is part of gold.
+
+// This program 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.
+
+// This program 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 this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+#ifndef GOLD_UTILS_H
+#define GOLD_UTILS_H
+
+namespace gold
+{
+// Utilities for manipulating integers of up to 32-bits
+
+namespace utils
+{
+  // Sign extend an n-bit unsigned integer stored in an uint32_t into
+  // an int32_t.  NO_BITS must be between 1 to 32.
+
+  template<int no_bits>
+  inline int32_t
+  sign_extend(uint32_t bits)
+  {
+    gold_assert(no_bits >= 0 && no_bits <= 32);
+    if (no_bits == 32)
+      return static_cast<int32_t>(bits);
+    uint32_t mask = (~((uint32_t) 0)) >> (32 - no_bits);
+    bits &= mask;
+    uint32_t top_bit = 1U << (no_bits - 1);
+    int32_t as_signed = static_cast<int32_t>(bits);
+    return (bits & top_bit) ? as_signed + (-top_bit * 2) : as_signed;
+  }
+
+  // Detects overflow of an NO_BITS integer stored in a uint32_t.
+
+  template<int no_bits>
+  inline bool
+  has_overflow(uint32_t bits)
+  {
+    gold_assert(no_bits >= 0 && no_bits <= 32);
+    if (no_bits == 32)
+      return false;
+    int32_t max = (1 << (no_bits - 1)) - 1;
+    int32_t min = -(1 << (no_bits - 1));
+    int32_t as_signed = static_cast<int32_t>(bits);
+    return as_signed > max || as_signed < min;
+  }
+
+  // Detects overflow of an NO_BITS integer stored in a uint32_t when it
+  // fits in the given number of bits as either a signed or unsigned value.
+  // For example, has_signed_unsigned_overflow<8> would check
+  // -128 <= bits <= 255
+
+  template<int no_bits>
+  inline bool
+  has_signed_unsigned_overflow(uint32_t bits)
+  {
+    gold_assert(no_bits >= 2 && no_bits <= 32);
+    if (no_bits == 32)
+      return false;
+    int32_t max = static_cast<int32_t>((1U << no_bits) - 1);
+    int32_t min = -(1 << (no_bits - 1));
+    int32_t as_signed = static_cast<int32_t>(bits);
+    return as_signed > max || as_signed < min;
+  }
+
+  // Select bits from A and B using bits in MASK.  For each n in [0..31],
+  // the n-th bit in the result is chosen from the n-th bits of A and B.
+  // A zero selects A and a one selects B.
+
+  inline uint32_t
+  bit_select(uint32_t a, uint32_t b, uint32_t mask)
+  { return (a & ~mask) | (b & mask); }
+} // End namespace utils.
+
+} // End namespace gold.
+
+#endif // !defined(GOLD_UTILS_H)
+