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[libc] FPRep builders return FPRep instead of raw StorageType #78588

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Merged
merged 4 commits into from
Jan 22, 2024
Merged

[libc] FPRep builders return FPRep instead of raw StorageType #78588

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49ba96c
[libc] `FPRep` builders return `FPRep` instead of raw `StorageType`
gchatelet Jan 18, 2024
e6fa7f7
New design
gchatelet Jan 22, 2024
a4ca0f1
Addressing comments
gchatelet Jan 22, 2024
2c6026e
Merge branch 'main' into fprep_builders_yield_fpreap_insteadof_storag…
gchatelet Jan 22, 2024
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68 changes: 36 additions & 32 deletions libc/src/__support/FPUtil/FPBits.h
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Original file line number Diff line number Diff line change
Expand Up @@ -332,7 +332,10 @@ struct FPRepBase : public internal::FPLayout<fp_type> {
mask_trailing_ones<StorageType, FRACTION_LEN>();

// The floating point number representation as an unsigned integer.
StorageType bits = 0;
StorageType bits;

LIBC_INLINE constexpr FPRepBase() : bits(0) {}
LIBC_INLINE constexpr FPRepBase(StorageType value) : bits(value) {}

public:
LIBC_INLINE constexpr Sign sign() const {
Expand Down Expand Up @@ -418,6 +421,7 @@ template <FPType fp_type> struct FPRep : public FPRepBase<fp_type> {
using UP::exp_bits;
using UP::exp_sig_bits;
using UP::sig_bits;
using UP::UP;

public:
LIBC_INLINE constexpr bool is_nan() const {
Expand Down Expand Up @@ -450,37 +454,35 @@ template <FPType fp_type> struct FPRep : public FPRepBase<fp_type> {
return is_finite() && !is_subnormal();
}

LIBC_INLINE static constexpr StorageType zero(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep zero(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ZEROES(), Significand::ZERO());
}
LIBC_INLINE static constexpr StorageType one(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep one(Sign sign = Sign::POS) {
return encode(sign, Exponent::ZERO(), Significand::ZERO());
}
LIBC_INLINE static constexpr StorageType
min_subnormal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep min_subnormal(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ZEROES(), Significand::LSB());
}
LIBC_INLINE static constexpr StorageType
max_subnormal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep max_subnormal(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ZEROES(),
Significand::BITS_ALL_ONES());
}
LIBC_INLINE static constexpr StorageType min_normal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep min_normal(Sign sign = Sign::POS) {
return encode(sign, Exponent::MIN(), Significand::ZERO());
}
LIBC_INLINE static constexpr StorageType max_normal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep max_normal(Sign sign = Sign::POS) {
return encode(sign, Exponent::MAX(), Significand::BITS_ALL_ONES());
}
LIBC_INLINE static constexpr StorageType inf(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep inf(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ONES(), Significand::ZERO());
}
LIBC_INLINE static constexpr StorageType build_nan(Sign sign = Sign::POS,
StorageType v = 0) {
LIBC_INLINE static constexpr FPRep build_nan(Sign sign = Sign::POS,
StorageType v = 0) {
return encode(sign, BiasedExponent::BITS_ALL_ONES(),
(v ? Significand(v) : (Significand::MSB() >> 1)));
}
LIBC_INLINE static constexpr StorageType
build_quiet_nan(Sign sign = Sign::POS, StorageType v = 0) {
LIBC_INLINE static constexpr FPRep build_quiet_nan(Sign sign = Sign::POS,
StorageType v = 0) {
return encode(sign, BiasedExponent::BITS_ALL_ONES(),
Significand::MSB() | Significand(v));
}
Expand All @@ -507,6 +509,7 @@ struct FPRep<FPType::X86_Binary80> : public FPRepBase<FPType::X86_Binary80> {
using typename UP::BiasedExponent;
using typename UP::Significand;
using UP::encode;
using UP::UP;

public:
// The x86 80 bit float represents the leading digit of the mantissa
Expand Down Expand Up @@ -570,38 +573,36 @@ struct FPRep<FPType::X86_Binary80> : public FPRepBase<FPType::X86_Binary80> {
return get_implicit_bit();
}

LIBC_INLINE static constexpr StorageType zero(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep zero(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ZEROES(), Significand::ZERO());
}
LIBC_INLINE static constexpr StorageType one(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep one(Sign sign = Sign::POS) {
return encode(sign, Exponent::ZERO(), Significand::MSB());
}
LIBC_INLINE static constexpr StorageType
min_subnormal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep min_subnormal(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ZEROES(), Significand::LSB());
}
LIBC_INLINE static constexpr StorageType
max_subnormal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep max_subnormal(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ZEROES(),
Significand::BITS_ALL_ONES() ^ Significand::MSB());
}
LIBC_INLINE static constexpr StorageType min_normal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep min_normal(Sign sign = Sign::POS) {
return encode(sign, Exponent::MIN(), Significand::MSB());
}
LIBC_INLINE static constexpr StorageType max_normal(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep max_normal(Sign sign = Sign::POS) {
return encode(sign, Exponent::MAX(), Significand::BITS_ALL_ONES());
}
LIBC_INLINE static constexpr StorageType inf(Sign sign = Sign::POS) {
LIBC_INLINE static constexpr FPRep inf(Sign sign = Sign::POS) {
return encode(sign, BiasedExponent::BITS_ALL_ONES(), Significand::MSB());
}
LIBC_INLINE static constexpr StorageType build_nan(Sign sign = Sign::POS,
StorageType v = 0) {
LIBC_INLINE static constexpr FPRep build_nan(Sign sign = Sign::POS,
StorageType v = 0) {
return encode(sign, BiasedExponent::BITS_ALL_ONES(),
Significand::MSB() |
(v ? Significand(v) : (Significand::MSB() >> 2)));
}
LIBC_INLINE static constexpr StorageType
build_quiet_nan(Sign sign = Sign::POS, StorageType v = 0) {
LIBC_INLINE static constexpr FPRep build_quiet_nan(Sign sign = Sign::POS,
StorageType v = 0) {
return encode(sign, BiasedExponent::BITS_ALL_ONES(),
Significand::MSB() | (Significand::MSB() >> 1) |
Significand(v));
Expand Down Expand Up @@ -671,14 +672,15 @@ template <typename T> struct FPBits : public internal::FPRep<get_fp_type<T>()> {

using UP::bits;
using UP::EXP_LEN;
using UP::UP;

// Constants.
static constexpr int MAX_BIASED_EXPONENT = (1 << EXP_LEN) - 1;
static constexpr StorageType MIN_NORMAL = UP::min_normal(Sign::POS);
static constexpr StorageType MAX_NORMAL = UP::max_normal(Sign::POS);
static constexpr StorageType MIN_SUBNORMAL = UP::min_subnormal(Sign::POS);
static constexpr StorageType MAX_SUBNORMAL = UP::max_subnormal(Sign::POS);
static constexpr StorageType MIN_NORMAL = UP::min_normal(Sign::POS).uintval();
static constexpr StorageType MAX_NORMAL = UP::max_normal(Sign::POS).uintval();
static constexpr StorageType MIN_SUBNORMAL =
UP::min_subnormal(Sign::POS).uintval();
static constexpr StorageType MAX_SUBNORMAL =
UP::max_subnormal(Sign::POS).uintval();

// Constructors.
LIBC_INLINE constexpr FPBits() = default;
Expand All @@ -687,6 +689,8 @@ template <typename T> struct FPBits : public internal::FPRep<get_fp_type<T>()> {
using Unqual = typename cpp::remove_cv_t<XType>;
if constexpr (cpp::is_same_v<Unqual, T>) {
bits = cpp::bit_cast<StorageType>(x);
} else if constexpr (cpp::is_same_v<Unqual, UP>) {
bits = x.uintval();
} else if constexpr (cpp::is_same_v<Unqual, StorageType>) {
bits = x;
} else {
Expand Down
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