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Fix for issue #19. #21

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Merged
merged 2 commits into from
Feb 3, 2022
Merged

Fix for issue #19. #21

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7ce8037
Fix for issue #19.
eteran Jan 19, 2022
ef0fe89
Fix constexpr usage where simply const is appropriate
eteran Feb 2, 2022
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21 changes: 12 additions & 9 deletions fixed/include/cpp-utilities/fixed.h
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,9 @@ namespace detail {
// from a type which is nice for the division op
template <size_t T>
struct type_from_size {
using value_type = void;
using unsigned_type = void;
using signed_type = void;
static constexpr bool is_specialized = false;
};

Expand Down Expand Up @@ -239,15 +242,15 @@ CONSTEXPR14 fixed<I,F> multiply(fixed<I, F> lhs, fixed<I, F> rhs, typename std::
constexpr base_type fractional_mask = fixed<I,F>::fractional_mask;

// more costly but doesn't need a larger type
constexpr base_type a_hi = (lhs.to_raw() & integer_mask) >> fractional_bits;
constexpr base_type b_hi = (rhs.to_raw() & integer_mask) >> fractional_bits;
constexpr base_type a_lo = (lhs.to_raw() & fractional_mask);
constexpr base_type b_lo = (rhs.to_raw() & fractional_mask);

constexpr base_type x1 = a_hi * b_hi;
constexpr base_type x2 = a_hi * b_lo;
constexpr base_type x3 = a_lo * b_hi;
constexpr base_type x4 = a_lo * b_lo;
const base_type a_hi = (lhs.to_raw() & integer_mask) >> fractional_bits;
const base_type b_hi = (rhs.to_raw() & integer_mask) >> fractional_bits;
const base_type a_lo = (lhs.to_raw() & fractional_mask);
const base_type b_lo = (rhs.to_raw() & fractional_mask);

const base_type x1 = a_hi * b_hi;
const base_type x2 = a_hi * b_lo;
const base_type x3 = a_lo * b_hi;
const base_type x4 = a_lo * b_lo;

return fixed<I,F>::from_base((x1 << fractional_bits) + (x3 + x2) + (x4 >> fractional_bits));
}
Expand Down