wasmi/src/nan_preserving_float.rs

218 lines
5.2 KiB
Rust

#![allow(missing_docs)]
#[cfg(not(feature = "std"))]
use libm::{F32Ext, F64Ext};
use core::cmp::{Ordering, PartialEq, PartialOrd};
use core::ops::{Add, Div, Mul, Neg, Rem, Sub};
macro_rules! impl_binop {
($for:ident, $is:ident, $op:ident, $func_name:ident) => {
impl<T: Into<$for>> $op<T> for $for {
type Output = Self;
fn $func_name(self, other: T) -> Self {
$for(
$op::$func_name($is::from_bits(self.0), $is::from_bits(other.into().0))
.to_bits(),
)
}
}
};
}
macro_rules! float {
($for:ident, $rep:ident, $is:ident) => {
float!(
$for,
$rep,
$is,
1 << (::core::mem::size_of::<$is>() * 8 - 1)
);
};
($for:ident, $rep:ident, $is:ident, $sign_bit:expr) => {
#[derive(Copy, Clone)]
pub struct $for($rep);
impl_binop!($for, $is, Add, add);
impl_binop!($for, $is, Sub, sub);
impl_binop!($for, $is, Mul, mul);
impl_binop!($for, $is, Div, div);
impl_binop!($for, $is, Rem, rem);
impl $for {
pub fn from_bits(other: $rep) -> Self {
$for(other)
}
pub fn to_bits(self) -> $rep {
self.0
}
pub fn from_float(fl: $is) -> Self {
fl.into()
}
pub fn to_float(self) -> $is {
self.into()
}
pub fn is_nan(self) -> bool {
self.to_float().is_nan()
}
pub fn abs(self) -> Self {
$for(self.0 & !$sign_bit)
}
pub fn fract(self) -> Self {
self.to_float().fract().into()
}
pub fn min(self, other: Self) -> Self {
Self::from(self.to_float().min(other.to_float()))
}
pub fn max(self, other: Self) -> Self {
Self::from(self.to_float().max(other.to_float()))
}
}
impl From<$is> for $for {
fn from(other: $is) -> $for {
$for(other.to_bits())
}
}
impl From<$for> for $is {
fn from(other: $for) -> $is {
<$is>::from_bits(other.0)
}
}
impl Neg for $for {
type Output = Self;
fn neg(self) -> Self {
$for(self.0 ^ $sign_bit)
}
}
impl<T: Into<$for> + Copy> PartialEq<T> for $for {
fn eq(&self, other: &T) -> bool {
$is::from(*self) == $is::from((*other).into())
}
}
impl<T: Into<$for> + Copy> PartialOrd<T> for $for {
fn partial_cmp(&self, other: &T) -> Option<Ordering> {
$is::from(*self).partial_cmp(&$is::from((*other).into()))
}
}
impl ::core::fmt::Debug for $for {
fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
$is::from(*self).fmt(f)
}
}
};
}
float!(F32, u32, f32);
float!(F64, u64, f64);
impl From<u32> for F32 {
fn from(other: u32) -> Self {
Self::from_bits(other)
}
}
impl From<F32> for u32 {
fn from(other: F32) -> Self {
other.to_bits()
}
}
impl From<u64> for F64 {
fn from(other: u64) -> Self {
Self::from_bits(other)
}
}
impl From<F64> for u64 {
fn from(other: F64) -> Self {
other.to_bits()
}
}
#[cfg(test)]
mod tests {
extern crate rand;
use self::rand::Rng;
use super::{F32, F64};
use core::{
fmt::Debug,
iter,
ops::{Add, Div, Mul, Neg, Sub},
};
fn test_ops<T, F, I>(iter: I)
where
T: Add<Output = T>
+ Div<Output = T>
+ Mul<Output = T>
+ Sub<Output = T>
+ Neg<Output = T>
+ Copy
+ Debug
+ PartialEq,
F: Into<T>
+ Add<Output = F>
+ Div<Output = F>
+ Mul<Output = F>
+ Sub<Output = F>
+ Neg<Output = F>
+ Copy
+ Debug,
I: IntoIterator<Item = (F, F)>,
{
for (a, b) in iter {
assert_eq!((a + b).into(), a.into() + b.into());
assert_eq!((a - b).into(), a.into() - b.into());
assert_eq!((a * b).into(), a.into() * b.into());
assert_eq!((a / b).into(), a.into() / b.into());
assert_eq!((-a).into(), -a.into());
assert_eq!((-b).into(), -b.into());
}
}
#[test]
fn test_ops_f32() {
let mut rng = rand::thread_rng();
let iter = iter::repeat(()).map(|_| rng.gen());
test_ops::<F32, f32, _>(iter.take(1000));
}
#[test]
fn test_ops_f64() {
let mut rng = rand::thread_rng();
let iter = iter::repeat(()).map(|_| rng.gen());
test_ops::<F64, f64, _>(iter.take(1000));
}
#[test]
fn test_neg_nan_f32() {
assert_eq!((-F32(0xff80_3210)).0, 0x7f80_3210);
}
#[test]
fn test_neg_nan_f64() {
assert_eq!((-F64(0xff80_3210_0000_0000)).0, 0x7f80_3210_0000_0000);
}
}