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Parameterized fp on significand type

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This commit is contained in:
Victor Zverovich
2022-02-20 11:33:16 -08:00
parent cf940ae82e
commit 4fcacea354
2 changed files with 22 additions and 15 deletions
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23
include/fmt/format-inl.h
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@@ -223,18 +223,20 @@ template <typename Float> constexpr int num_significand_bits() {
}
// A floating-point number f * pow(2, e).
struct fp {
uint64_t f;
template <typename F> struct basic_fp {
F f;
int e;
static constexpr const int num_significand_bits = bits<decltype(f)>::value;
static constexpr const int num_significand_bits = bits<F>::value;
constexpr fp() : f(0), e(0) {}
constexpr fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
constexpr basic_fp() : f(0), e(0) {}
constexpr basic_fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
// Constructs fp from an IEEE754 floating-point number. It is a template to
// prevent compile errors on systems where n is not IEEE754.
template <typename Float> explicit FMT_CONSTEXPR fp(Float n) { assign(n); }
template <typename Float> explicit FMT_CONSTEXPR basic_fp(Float n) {
assign(n);
}
template <typename Float>
using is_supported = bool_constant<std::numeric_limits<Float>::digits <= 64>;
@@ -272,8 +274,11 @@ struct fp {
}
};
using fp = basic_fp<unsigned long long>;
// Normalizes the value converted from double and multiplied by (1 << SHIFT).
template <int SHIFT = 0> FMT_CONSTEXPR fp normalize(fp value) {
template <int SHIFT = 0, typename F>
FMT_CONSTEXPR basic_fp<F> normalize(basic_fp<F> value) {
// Handle subnormals.
const uint64_t implicit_bit = 1ULL << num_significand_bits<double>();
const auto shifted_implicit_bit = implicit_bit << SHIFT;
@@ -289,7 +294,9 @@ template <int SHIFT = 0> FMT_CONSTEXPR fp normalize(fp value) {
return value;
}
inline bool operator==(fp x, fp y) { return x.f == y.f && x.e == y.e; }
template <typename F> inline bool operator==(basic_fp<F> x, basic_fp<F> y) {
return x.f == y.f && x.e == y.e;
}
// Computes lhs * rhs / pow(2, 64) rounded to nearest with half-up tie breaking.
FMT_CONSTEXPR inline uint64_t multiply(uint64_t lhs, uint64_t rhs) {