Struct Format 

pub struct Format {
    pub p: u32,
    pub width: u32,
    pub bias: i32,
}

The parameters of an IEEE-754 binary interchange format.

Held as data rather than as a type parameter so that one implementation serves both precisions. A second copy of this logic specialized per format is exactly how the two diverge.

Fields

p: u32

Significand bits including the implicit leading one (24 / 53).

width: u32

Total width in bits (32 / 64).

bias: i32

Exponent bias (127 / 1023).

Implementations

impl Format

pub const fn man_bits(self) -> u32

Stored mantissa bits — one fewer than Format::p, the implicit bit not being stored.

pub const fn max_biased(self) -> u32

The all-ones exponent field, which encodes infinity and NaN.

pub const fn min_lsb_exp(self) -> i32

The exponent of the least significant bit of the smallest subnormal — -149 for f32, -1074 for f64.

This is the floor the rounding step clamps to, and it is what makes a result subnormal rather than merely small.

pub const fn max_finite(self) -> u64

The largest finite value’s encoding, magnitude only.

pub const fn infinity(self) -> u64

Positive infinity, magnitude only.

pub const fn default_nan(self) -> u64

The NaN the VR4300 delivers as the result of an invalid operation.

0x7FBF_FFFF / 0x7FF7_FFFF_FFFF_FFFF — the significand’s MSB is clear, which by IEEE-754:2008 would make the result of every invalid operation a signaling NaN, absurdly re-trapping on first use.

It is not absurd, because the VR4300 uses the legacy MIPS convention, where MSB set means signaling. Under its own rules this is an ordinary quiet NaN. See fpu::is_snan_f32 and accuracy ledger C-12; this value is the corroboration that the convention really is inverted rather than the tests being odd.

Trait Implementations

impl Clone for Format

fn clone(&self) -> Format

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Format

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Format

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Format

fn eq(&self, other: &Format) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Format

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for Format

impl Eq for Format

impl StructuralPartialEq for Format