Merge pull request #714 from cppalliance/decimal32_fast_comps_v2

Decimal32 fast comps v2

include/boost/decimal/decimal32_fast.hpp

@@ -464,12 +464,7 @@ constexpr auto issignaling(decimal32_fast val) noexcept -> bool
 
 constexpr auto isnormal(decimal32_fast val) noexcept -> bool
 {
- if (val.exponent_ <= static_cast<std::uint8_t>(detail::precision_v<decimal32> - 1))
- {
- return false;
- }
-
- return (val.significand_ != 0) && isfinite(val);
+ return (val.significand_ != 0) && isfinite(val) && (val.exponent_ > static_cast<std::uint8_t>(detail::precision_v<decimal32> - 1));
 }
 
 constexpr auto isfinite(decimal32_fast val) noexcept -> bool
@@ -479,21 +474,24 @@ constexpr auto isfinite(decimal32_fast val) noexcept -> bool
 
 constexpr auto operator==(decimal32_fast lhs, decimal32_fast rhs) noexcept -> bool
 {
- #ifndef BOOST_DECIMAL_FAST_MATH
- if (isnan(lhs) || isnan(rhs))
- {
- return false;
- }
- #endif
-
- return (lhs.sign_ == rhs.sign_) &
- (lhs.exponent_ == rhs.exponent_) &
+ return
+ #ifndef BOOST_DECIMAL_FAST_MATH
+ !isnan(lhs) && !isnan(rhs) &&
+ #endif
+ (lhs.sign_ == rhs.sign_) &&
+ (lhs.exponent_ == rhs.exponent_) &&
  (lhs.significand_ == rhs.significand_);
 }
 
 constexpr auto operator!=(decimal32_fast lhs, decimal32_fast rhs) noexcept -> bool
 {
- return !(lhs == rhs);
+ return
+ #ifndef BOOST_DECIMAL_FAST_MATH
+ isnan(lhs) || isnan(rhs) ||
+ #endif
+ (lhs.sign_ != rhs.sign_) ||
+ (lhs.exponent_ != rhs.exponent_) ||
+ (lhs.significand_ != rhs.significand_);
 }
 
 constexpr auto operator<(decimal32_fast lhs, decimal32_fast rhs) noexcept -> bool
@@ -521,42 +519,37 @@ constexpr auto operator<(decimal32_fast lhs, decimal32_fast rhs) noexcept -> boo
  }
  #endif
 
- if (lhs.significand_ == 0 || rhs.significand_ == 0)
- {
- if (lhs.significand_ == 0 && rhs.significand_ == 0)
- {
- #ifndef BOOST_DECIMAL_FAST_MATH
- return lhs.sign_ && !rhs.sign_;
- #else
- return false;
- #endif
- }
- return lhs.significand_ == 0 ? !rhs.sign_ : lhs.sign_;
- }
-
- if (lhs.sign_ != rhs.sign_)
- {
- return lhs.sign_;
- }
-
- if (lhs.exponent_ != rhs.exponent_)
- {
- return lhs.sign_ ? lhs.exponent_ > rhs.exponent_ : lhs.exponent_ < rhs.exponent_;
- }
-
- return lhs.sign_ ? lhs.significand_ > rhs.significand_ : lhs.significand_ < rhs.significand_;
+ return fast_type_less_parts_impl(lhs.significand_, lhs.biased_exponent(), lhs.sign_,
+ rhs.significand_, rhs.biased_exponent(), rhs.sign_);
 }
 
 constexpr auto operator<=(decimal32_fast lhs, decimal32_fast rhs) noexcept -> bool
 {
  #ifndef BOOST_DECIMAL_FAST_MATH
- if (isnan(lhs) || isnan(rhs))
+ if (!isfinite(lhs) || !isfinite(rhs))
  {
- return false;
+ if (isnan(lhs) || isnan(rhs) ||
+ (!lhs.isneg() && rhs.isneg()))
+ {
+ return false;
+ }
+ else if (lhs.isneg() && !rhs.isneg())
+ {
+ return true;
+ }
+ else if (isfinite(lhs) && isinf(rhs))
+ {
+ return !signbit(rhs);
+ }
+ else if (isinf(lhs) && isfinite(rhs))
+ {
+ return signbit(rhs);
+ }
  }
  #endif
 
- return !(rhs < lhs);
+ return !fast_type_less_parts_impl(rhs.significand_, rhs.biased_exponent(), rhs.sign_,
+ lhs.significand_, lhs.biased_exponent(), lhs.sign_);
 }
 
 constexpr auto operator>(decimal32_fast lhs, decimal32_fast rhs) noexcept -> bool
@@ -567,13 +560,29 @@ constexpr auto operator>(decimal32_fast lhs, decimal32_fast rhs) noexcept -> boo
 constexpr auto operator>=(decimal32_fast lhs, decimal32_fast rhs) noexcept -> bool
 {
  #ifndef BOOST_DECIMAL_FAST_MATH
- if (isnan(lhs) || isnan(rhs))
+ if (!isfinite(lhs) || !isfinite(rhs))
  {
- return false;
+ if (isnan(lhs) || isnan(rhs))
+ {
+ return false;
+ }
+ else if (lhs.isneg() && !rhs.isneg())
+ {
+ return false;
+ }
+ else if (isfinite(lhs) && isinf(rhs))
+ {
+ return signbit(rhs);
+ }
+ else if (isinf(lhs) && isfinite(rhs))
+ {
+ return !signbit(lhs);
+ }
  }
  #endif
 
- return !(lhs < rhs);
+ return !fast_type_less_parts_impl(lhs.significand_, lhs.biased_exponent(), lhs.sign_,
+ rhs.significand_, rhs.biased_exponent(), rhs.sign_);
 }
 
 template <typename Integer>

include/boost/decimal/detail/comparison.hpp

@@ -167,6 +167,36 @@ constexpr auto operator!=(Decimal1 lhs, Decimal2 rhs) noexcept
  return !(mixed_decimal_equality_impl(lhs, rhs));
 }
 
+template <BOOST_DECIMAL_INTEGRAL T, BOOST_DECIMAL_INTEGRAL U>
+BOOST_DECIMAL_FORCE_INLINE constexpr auto fast_type_less_parts_impl(T lhs_sig, U lhs_exp, bool lhs_sign,
+ T rhs_sig, U rhs_exp, bool rhs_sign) noexcept -> bool
+{
+ if (lhs_sig == 0 || rhs_sig == 0)
+ {
+ if (lhs_sig == 0 && rhs_sig == 0)
+ {
+ #ifndef BOOST_DECIMAL_FAST_MATH
+ return lhs_sign && !rhs_sign;
+ #else
+ return false;
+ #endif
+ }
+ return lhs_sig == 0 ? !rhs_sign : lhs_sign;
+ }
+
+ if (lhs_sign != rhs_sign)
+ {
+ return lhs_sign;
+ }
+
+ if (lhs_exp != rhs_exp)
+ {
+ return lhs_sign ? lhs_exp > rhs_exp : lhs_exp < rhs_exp;
+ }
+
+ return lhs_sign ? lhs_sig > rhs_sig : lhs_sig < rhs_sig;
+}
+
 template <BOOST_DECIMAL_DECIMAL_FLOATING_TYPE DecimalType = decimal32, BOOST_DECIMAL_INTEGRAL T1,
  BOOST_DECIMAL_INTEGRAL U1, BOOST_DECIMAL_INTEGRAL T2, BOOST_DECIMAL_INTEGRAL U2>
 constexpr auto less_parts_impl(T1 lhs_sig, U1 lhs_exp, bool lhs_sign,