Subject: [Boost-commit] svn:boost r83401 - in sandbox/big_number/boost/multiprecision: . detail
From: e_float_at_[hidden]
Date: 2013-03-10 15:26:53
Author: christopher_kormanyos
Date: 2013-03-10 15:26:52 EDT (Sun, 10 Mar 2013)
New Revision: 83401
URL: http://svn.boost.org/trac/boost/changeset/83401
Log:
Progress with cpp_bin_float.
Text files modified:
sandbox/big_number/boost/multiprecision/cpp_bin_float.hpp | 74 +++++++++++++++++++++------------------
sandbox/big_number/boost/multiprecision/detail/utype_helper.hpp | 23 ++++++++++++
2 files changed, 63 insertions(+), 34 deletions(-)
Modified: sandbox/big_number/boost/multiprecision/cpp_bin_float.hpp
==============================================================================
--- sandbox/big_number/boost/multiprecision/cpp_bin_float.hpp (original)
+++ sandbox/big_number/boost/multiprecision/cpp_bin_float.hpp 2013-03-10 15:26:52 EDT (Sun, 10 Mar 2013)
@@ -83,6 +83,8 @@
static const boost::uint32_t cpp_bin_float_elem_number = boost::uint32_t(cpp_bin_float_bits_number / std::numeric_limits<short_limb_type>::digits)
+ (boost::uint32_t(cpp_bin_float_bits_number % std::numeric_limits<short_limb_type>::digits) != boost::uint32_t(0U) ? 1U : 0U);
+ // TBD: Right-justify the data in the data array (seems to be standard established by GMP, etc.).
+
typedef mpl::list<eval_ops_signed_type> signed_types;
typedef mpl::list<eval_ops_unsigned_type> unsigned_types;
typedef mpl::list<eval_ops_float_type> float_types;
@@ -116,7 +118,7 @@
my_fpclass (cpp_bin_float_finite),
my_precision_in_bits(cpp_bin_float_bits_number)
{
- from_unsigned_integer_type(ui);
+ from_unsigned_integer_type<unsigned_integer_type>(ui);
round_and_truncate();
}
@@ -170,7 +172,7 @@
my_fpclass (less_eq_other.my_fpclass),
my_precision_in_bits(less_eq_other.my_precision_in_bits)
{
- // TBD: Handle limb types larger and smaller the limb type of *this.
+ // TBD: Handle other limb types both larger and smaller than the limb type of *this.
std::copy(less_eq_other.my_data.begin(),
less_eq_other.my_data.begin() + less_eq_other.cpp_bin_float_elem_number,
my_data.begin());
@@ -199,7 +201,7 @@
my_precision_in_bits(cpp_bin_float_bits_number)
{
// TBD: Do a proper rounding here.
- // TBD: Handle limb types both larger and smaller the limb type of *this.
+ // TBD: Handle other limb types both larger and smaller than the limb type of *this.
std::copy(larger_other.my_data.begin(),
larger_other.my_data.begin() + cpp_bin_float_elem_number,
my_data.begin());
@@ -219,7 +221,7 @@
}
else
{
- from_float_type(static_cast<float_type>(a));
+ from_float_type(a);
}
round_and_truncate();
@@ -281,16 +283,37 @@
{
boost::uint_least8_t i = boost::uint_least8_t(0U);
- while(u != unsigned_integer_type(0U))
+ for(;;)
{
my_data[i] = short_limb_type(u);
+
++i;
+
u >>= std::numeric_limits<short_limb_type>::digits;
- my_exp += std::numeric_limits<short_limb_type>::digits;
+
+ if(u != unsigned_integer_type(0U))
+ {
+ my_exp += std::numeric_limits<short_limb_type>::digits;
+ }
+ else
+ {
+ break;
+ }
}
std::reverse(my_data.begin(), my_data.begin() + i);
}
+
+ const int priority_bit = boost::multiprecision::detail::utype_prior(my_data[0U]);
+
+ if(priority_bit < (std::numeric_limits<short_limb_type>::digits - 1))
+ {
+ const int shift = std::numeric_limits<short_limb_type>::digits - (1 + priority_bit);
+
+ shift_data_to_the_left(shift);
+
+ my_exp -= shift;
+ }
}
template<class float_type>
@@ -303,37 +326,11 @@
my_exp = static_cast<my_exponent_type>(e2);
- int delta_exp = int(my_exp % std::numeric_limits<short_limb_type>::digits);
-
int number_of_digits;
- unsigned i = 0U;
-
- if(delta_exp != 0)
- {
- if(delta_exp > 0)
- {
- y *= (short_limb_type(1U) << delta_exp);
- number_of_digits = delta_exp;
- my_exp -= delta_exp;
- }
- else
- {
- y *= (short_limb_type(1U) << (std::numeric_limits<short_limb_type>::digits + delta_exp));
- number_of_digits = std::numeric_limits<short_limb_type>::digits + delta_exp;
- my_exp -= (std::numeric_limits<short_limb_type>::digits + delta_exp);
- }
-
- my_data[i] = static_cast<short_limb_type>(y);
- y -= my_data[i];
- ++i;
- }
- else
- {
- number_of_digits = 0U;
- }
+ typename array_type::size_type i(0U);
- while(number_of_digits < boost::uint_least16_t(std::numeric_limits<float_type>::digits))
+ while(number_of_digits < std::numeric_limits<float_type>::digits)
{
if((std::numeric_limits<float_type>::digits - number_of_digits) >= std::numeric_limits<short_limb_type>::digits)
{
@@ -399,6 +396,15 @@
// TBD: Round and truncate the data.
}
+ void shift_data_to_the_left(const int shift)
+ {
+ // TBD: Shift data to the left.
+ }
+
+ void shift_data_to_the_right(const int shift)
+ {
+ // TBD: Shift data to the right.
+ }
} // namespace backends
using boost::multiprecision::backends::cpp_bin_float;
Modified: sandbox/big_number/boost/multiprecision/detail/utype_helper.hpp
==============================================================================
--- sandbox/big_number/boost/multiprecision/detail/utype_helper.hpp (original)
+++ sandbox/big_number/boost/multiprecision/detail/utype_helper.hpp 2013-03-10 15:26:52 EDT (Sun, 10 Mar 2013)
@@ -8,6 +8,7 @@
#ifndef BOOST_MP_UTYPE_HELPER_HPP
#define BOOST_MP_UTYPE_HELPER_HPP
+ #include <limits>
#include <boost/cstdint.hpp>
namespace boost { namespace multiprecision {
@@ -82,6 +83,28 @@
template<> struct utype_helper<62U> { typedef boost::uint64_t exact; };
template<> struct utype_helper<63U> { typedef boost::uint64_t exact; };
template<> struct utype_helper<64U> { typedef boost::uint64_t exact; };
+
+ template<class unsigned_type>
+ int utype_prior(unsigned_type ui)
+ {
+ // TBD: Implement a templated binary search for this.
+ int priority_bit;
+
+ unsigned_type priority_mask = unsigned_type(unsigned_type(1U) << (std::numeric_limits<unsigned_type>::digits - 1));
+
+ for(priority_bit = std::numeric_limits<unsigned_type>::digits - 1; priority_bit >= 0; --priority_bit)
+ {
+ if(unsigned_type(priority_mask & ui) != unsigned_type(0U))
+ {
+ break;
+ }
+
+ priority_mask >>= 1;
+ }
+
+ return priority_bit;
+ }
+
} } }
#endif // BOOST_MP_UTYPE_HELPER_HPP