Initial support for artificially small limbs.

1 files changed, 127 insertions, 0 deletions

diff --git a/asl.h b/asl.h
new file mode 100644
index 000000000..64deea068
--- /dev/null
+++ b/asl.h
@@ -0,0 +1,127 @@
+/* asl.h -- artificially small limbs support by means of C++ operator
+   overloading.
+
+Copyright 2016 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of either:
+
+  * the GNU Lesser General Public License as published by the Free
+    Software Foundation; either version 3 of the License, or (at your
+    option) any later version.
+
+or
+
+  * the GNU General Public License as published by the Free Software
+    Foundation; either version 2 of the License, or (at your option) any
+    later version.
+
+or both in parallel, as here.
+
+The GNU MP Library 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 copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library.  If not,
+see https://www.gnu.org/licenses/.  */
+
+#include <iostream>
+#include <cstdint>
+#include <cstdlib>
+// #include <stdexcept>
+
+#ifndef GMP_ASSERT_ALWAYS
+#define GMP_ASSERT_ALWAYS(cc) do {if (!(cc)) abort();} while (0)
+#endif
+
+// Missing: post++ post-- ++pre --prec bool(limb) !limb
+
+#ifndef GMP_LIMB_BITS
+#define GMP_LIMB_BITS 4
+#endif
+
+#define GMP_NUMB_MASK (2 * (1ul << (GMP_LIMB_BITS - 1)) - 1)
+
+#define BINOP_MASK(op, type)				\
+  mp_limb_t& operator op##=(const type& rhs) {		\
+    limbo = (limbo op rhs.limbo) & GMP_NUMB_MASK;	\
+    return *this;					\
+  }
+#define BINOP_NOMASK(op, type)				\
+  mp_limb_t& operator op##=(const type& rhs) {		\
+    limbo = limbo op rhs.limbo;				\
+    return *this;					\
+  }
+
+typedef std::conditional<(GMP_NUMB_MASK <= 0xffff), uint16_t, uint32_t >::type type24;
+typedef std::conditional<(GMP_NUMB_MASK <= 0xff), uint8_t, type24>::type mtype;
+
+class mp_limb_t {
+public:
+  mp_limb_t() {}	// put random garbage in limbo?
+  mp_limb_t(const unsigned int rhs) { limbo = rhs & GMP_NUMB_MASK; }
+  // mp_limb_t(const mp_limb_t& rhs) { limbo = rhs.limbo; } // Causes havoc
+  BINOP_MASK(+, mp_limb_t)
+  BINOP_MASK(-, mp_limb_t)
+  BINOP_MASK(*, mp_limb_t)
+  BINOP_NOMASK(/, mp_limb_t)
+  BINOP_NOMASK(%, mp_limb_t)
+  BINOP_NOMASK(&, mp_limb_t)
+  BINOP_NOMASK(|, mp_limb_t)
+  BINOP_NOMASK(^, mp_limb_t)
+  mp_limb_t& operator<<=(const unsigned int rhs) {
+    GMP_ASSERT_ALWAYS (rhs < GMP_LIMB_BITS);
+    limbo = (limbo << rhs) & GMP_NUMB_MASK;
+    return *this;
+  }
+  mp_limb_t& operator>>=(const unsigned int rhs) {
+    GMP_ASSERT_ALWAYS (rhs < GMP_LIMB_BITS);
+    limbo = limbo >> rhs;
+    return *this;
+  }
+  mp_limb_t operator-() {
+    return static_cast<mp_limb_t>((-limbo) & GMP_NUMB_MASK);
+    // mp_limb_t x;  x.limbo = (-limbo) & GMP_NUMB_MASK;  return x;
+  }
+  mp_limb_t operator~() {
+    return static_cast<mp_limb_t>((~limbo) & GMP_NUMB_MASK);
+    // mp_limb_t x;  x.limbo = (~limbo) & GMP_NUMB_MASK;  return x;
+  }
+  operator unsigned int() const { return limbo; }
+  operator          int() const { return limbo; }
+
+#define RELOP(op)							\
+  inline bool operator op(const mp_limb_t rhs) {			\
+    return limbo op rhs.limbo;						\
+  }
+  RELOP(==)
+  RELOP(!=)
+  RELOP(<)
+  RELOP(>)
+  RELOP(<=)
+  RELOP(>=)
+
+private:
+  mtype limbo;
+};
+
+#define BINOP2(op, type)						\
+  inline mp_limb_t operator op(mp_limb_t lhs, const type& rhs) {	\
+    lhs op##= rhs;							\
+    return lhs;								\
+  }
+
+BINOP2(+, mp_limb_t)
+BINOP2(-, mp_limb_t)
+BINOP2(*, mp_limb_t)
+BINOP2(/, mp_limb_t)
+BINOP2(%, mp_limb_t)
+BINOP2(&, mp_limb_t)
+BINOP2(|, mp_limb_t)
+BINOP2(^, mp_limb_t)
+BINOP2(<<, unsigned int)
+BINOP2(>>, unsigned int)