use crate::wide::impl_methods;
use crate::{Rng, SplitMix32};
use ::wide::{u32x4, u32x8, u32x16};
macro_rules! impl_xorshift32_variants {
($size:expr) => {
::pastey::paste! {
#[doc = concat!("Xorshift32 producing ", stringify!($size), " values per call via `wide` SIMD vectors.")]
#[doc = ""]
#[doc = "Portable-SIMD counterpart of [`crate::rng32::Xorshift32`]. A shift-register generator;"]
#[doc = "each `nextu` call returns an array of `u32`, one per lane."]
#[doc = ""]
#[doc = "# Example"]
#[doc = "```"]
#[doc = concat!("use urng::wide::Xorshift32x", stringify!($size), ";")]
#[doc = ""]
#[doc = concat!("let mut rng = Xorshift32x", stringify!($size), "::new(1);")]
#[doc = concat!("let v = rng.nextu();")]
#[doc = concat!("assert_eq!(v.len(), ", stringify!($size), ");")]
#[doc = "```"]
#[allow(dead_code)]
#[repr(C, align(64))]
pub struct [<Xorshift32x $size>] {
a: [<u32x $size>],
}
#[allow(dead_code)]
impl [<Xorshift32x $size>] {
#[doc = "Creates a new generator, seeding the single shift-register word of every lane from `seed`."]
pub fn new(seed: u32) -> Self {
let mut seedgen = SplitMix32::new(seed);
Self {
a: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
}
}
#[doc = "Generates the next block of `u32` values, one per SIMD lane."]
#[doc = ""]
#[doc = "Applies the Xorshift32 scramble: `x ^= x << 13; x ^= x >> 17; x ^= x << 5`."]
#[inline(always)]
pub fn nextu(&mut self) -> [u32; $size] {
let x = self.a;
self.a = x ^ (x << 13);
self.a ^= self.a >> 17;
self.a ^= self.a << 5;
bytemuck::cast(self.a)
}
impl_methods!($size, 32);
}
}
};
($($size:expr),+ $(,)*) => {
$(impl_xorshift32_variants!($size);)+
};
}
macro_rules! impl_xorshift128_variants {
($size:expr) => {
::pastey::paste! {
#[doc = concat!("Xorshift128 producing ", stringify!($size), " values per call via `wide` SIMD vectors.")]
#[doc = ""]
#[doc = "Portable-SIMD counterpart of [`crate::rng32::Xorshift128`]. A 128-bit internal state;"]
#[doc = "each `nextu` call returns an array of `u32`, one per lane."]
#[doc = ""]
#[doc = "# Example"]
#[doc = "```"]
#[doc = concat!("use urng::wide::Xorshift128x", stringify!($size), ";")]
#[doc = ""]
#[doc = concat!("let mut rng = Xorshift128x", stringify!($size), "::new(1);")]
#[doc = concat!("let v = rng.nextu();")]
#[doc = concat!("assert_eq!(v.len(), ", stringify!($size), ");")]
#[doc = "```"]
#[allow(dead_code)]
#[repr(C, align(64))]
pub struct [<Xorshift128x $size>] {
x0: [<u32x $size>],
x1: [<u32x $size>],
x2: [<u32x $size>],
x3: [<u32x $size>],
}
#[allow(dead_code)]
impl [<Xorshift128x $size>] {
#[doc = "Creates a new generator, seeding the four state words of every lane from `seed`."]
pub fn new(seed: u32) -> Self {
let mut seedgen = SplitMix32::new(seed);
Self {
x0: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
x1: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
x2: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
x3: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
}
}
#[doc = "Generates the next block of `u32` values, one per SIMD lane."]
#[doc = ""]
#[doc = "Applies the Xorshift128 scramble over the 128-bit state."]
#[inline(always)]
pub fn nextu(&mut self) -> [u32; $size] {
let mut t = self.x3;
t ^= t << 11;
t ^= t >> 8;
let s = self.x0;
self.x3 = self.x2;
self.x2 = self.x1;
self.x1 = s;
self.x0 = t ^ s ^ (s >> 19);
bytemuck::cast(self.x0)
}
impl_methods!($size, 32);
}
}
};
($($size:expr),+ $(,)*) => {
$(impl_xorshift128_variants!($size);)+
};
}
macro_rules! impl_xorwow_variants {
($size:expr) => {
::pastey::paste! {
#[doc = concat!("Xorwow producing ", stringify!($size), " values per call via `wide` SIMD vectors.")]
#[doc = ""]
#[doc = "Portable-SIMD counterpart of [`crate::rng32::Xorwow`]. Combines a Xorshift state with a"]
#[doc = "Weyl (linear) counter; each `nextu` call returns an array of `u32`, one per lane."]
#[doc = ""]
#[doc = "# Example"]
#[doc = "```"]
#[doc = concat!("use urng::wide::Xorwowx", stringify!($size), ";")]
#[doc = ""]
#[doc = concat!("let mut rng = Xorwowx", stringify!($size), "::new(1);")]
#[doc = concat!("let v = rng.nextu();")]
#[doc = concat!("assert_eq!(v.len(), ", stringify!($size), ");")]
#[doc = "```"]
#[allow(dead_code)]
#[repr(C, align(64))]
pub struct [<Xorwowx $size>] {
x0: [<u32x $size>],
x1: [<u32x $size>],
x2: [<u32x $size>],
x3: [<u32x $size>],
x4: [<u32x $size>],
c: [<u32x $size>],
}
#[allow(dead_code)]
impl [<Xorwowx $size>] {
#[doc = "Creates a new generator, seeding the five state words and the Weyl counter of every lane from `seed`."]
pub fn new(seed: u32) -> Self {
let mut seedgen = SplitMix32::new(seed);
Self {
x0: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
x1: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
x2: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
x3: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
x4: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
c: [<u32x $size>]::from([0u32; $size].map(|_| seedgen.nextu())),
}
}
#[doc = "Generates the next block of `u32` values, one per SIMD lane."]
#[doc = ""]
#[doc = "Applies the Xorwow scramble and adds the advancing Weyl counter."]
#[inline(always)]
pub fn nextu(&mut self) -> [u32; $size] {
let mut t = self.x4;
let s = self.x0;
self.x4 = self.x3;
self.x3 = self.x2;
self.x2 = self.x1;
self.x1 = s;
t ^= t >> 2;
t ^= t << 1;
t ^= s ^ (s << 4);
self.x0 = t;
self.c += [<u32x $size>]::splat(362437);
bytemuck::cast(t + self.c)
}
impl_methods!($size, 32);
}
}
};
($($size:expr),+ $(,)*) => {
$(impl_xorwow_variants!($size);)+
};
}
impl_xorshift32_variants!(4, 8, 16);
impl_xorshift128_variants!(4, 8, 16);
impl_xorwow_variants!(4, 8, 16);
#[cfg(test)]
mod tests {
use super::*;
crate::safe_test!(Xorshift32x4);
crate::safe_test!(Xorshift32x8);
crate::safe_test!(Xorshift32x16);
crate::safe_test!(Xorshift128x4);
crate::safe_test!(Xorshift128x8);
crate::safe_test!(Xorshift128x16);
crate::safe_test!(Xorwowx4);
crate::safe_test!(Xorwowx8);
crate::safe_test!(Xorwowx16);
}