compiler-builtins-zynq/src/float/mod.rs

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2016-08-18 04:51:37 +08:00
use core::mem;
pub mod add;
/// Trait for some basic operations on floats
pub trait Float: Sized {
/// A uint of the same with as the float
type Int;
/// Returns the bitwidth of the float type
fn bits() -> u32;
/// Returns the bitwidth of the significand
fn significand_bits() -> u32;
/// Returns `self` transmuted to `Self::Int`
fn repr(self) -> Self::Int;
#[cfg(test)]
/// Checks if two floats have the same bit representation. *Except* for NaNs! NaN can be
/// represented in multiple different ways. This methods returns `true` if two NaNs are
/// compared.
fn eq_repr(self, rhs: Self) -> bool;
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/// Returns a `Self::Int` transmuted back to `Self`
fn from_repr(a: Self::Int) -> Self;
/// Returns (normalized exponent, normalized significand)
fn normalize(significand: Self::Int) -> (i32, Self::Int);
}
impl Float for f32 {
type Int = u32;
fn bits() -> u32 {
32
}
fn significand_bits() -> u32 {
23
}
fn repr(self) -> Self::Int {
unsafe { mem::transmute(self) }
}
#[cfg(test)]
fn eq_repr(self, rhs: Self) -> bool {
if self.is_nan() && rhs.is_nan() {
true
} else {
self.repr() == rhs.repr()
}
}
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fn from_repr(a: Self::Int) -> Self {
unsafe { mem::transmute(a) }
}
fn normalize(significand: Self::Int) -> (i32, Self::Int) {
let shift = significand.leading_zeros()
.wrapping_sub((1u32 << Self::significand_bits()).leading_zeros());
(1i32.wrapping_sub(shift as i32), significand << shift as Self::Int)
}
}
impl Float for f64 {
type Int = u64;
fn bits() -> u32 {
64
}
fn significand_bits() -> u32 {
52
}
fn repr(self) -> Self::Int {
unsafe { mem::transmute(self) }
}
#[cfg(test)]
fn eq_repr(self, rhs: Self) -> bool {
if self.is_nan() && rhs.is_nan() {
true
} else {
self.repr() == rhs.repr()
}
}
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fn from_repr(a: Self::Int) -> Self {
unsafe { mem::transmute(a) }
}
fn normalize(significand: Self::Int) -> (i32, Self::Int) {
let shift = significand.leading_zeros()
.wrapping_sub((1u64 << Self::significand_bits()).leading_zeros());
(1i32.wrapping_sub(shift as i32), significand << shift as Self::Int)
}
}