2021-05-06 01:59:16 +00:00
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#![macro_use]
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2021-05-06 18:33:29 +00:00
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2021-05-09 23:19:07 +00:00
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use core::future::Future;
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use core::task::Poll;
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use embassy::traits;
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use embassy::util::{AtomicWaker, Unborrow};
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2021-07-29 11:44:51 +00:00
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use embassy_hal_common::unborrow;
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2021-05-09 23:19:07 +00:00
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use futures::future::poll_fn;
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use rand_core::{CryptoRng, RngCore};
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2021-05-06 18:33:29 +00:00
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2021-05-09 23:19:07 +00:00
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use crate::pac;
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2021-06-03 15:09:29 +00:00
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use crate::peripherals;
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2021-05-06 18:33:29 +00:00
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2021-05-13 18:28:53 +00:00
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pub(crate) static RNG_WAKER: AtomicWaker = AtomicWaker::new();
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2021-04-26 18:11:46 +00:00
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2021-08-26 18:03:54 +00:00
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#[cfg_attr(feature = "defmt", derive(defmt::Format))]
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2021-05-14 14:11:43 +00:00
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pub enum Error {
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SeedError,
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ClockError,
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}
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2021-04-26 18:11:46 +00:00
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pub struct Random<T: Instance> {
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2021-05-11 04:34:10 +00:00
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_inner: T,
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2021-04-26 18:11:46 +00:00
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}
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impl<T: Instance> Random<T> {
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2021-05-09 23:19:07 +00:00
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pub fn new(inner: impl Unborrow<Target = T>) -> Self {
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2021-06-09 11:54:53 +00:00
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T::enable();
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T::reset();
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2021-04-26 18:11:46 +00:00
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unborrow!(inner);
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2021-05-11 04:34:10 +00:00
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let mut random = Self { _inner: inner };
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2021-05-06 20:38:53 +00:00
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random.reset();
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random
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}
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pub fn reset(&mut self) {
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unsafe {
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T::regs().cr().modify(|reg| {
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reg.set_rngen(true);
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reg.set_ie(true);
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});
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T::regs().sr().modify(|reg| {
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reg.set_seis(false);
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reg.set_ceis(false);
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});
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}
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// Reference manual says to discard the first.
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let _ = self.next_u32();
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2021-04-26 18:11:46 +00:00
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}
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}
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2021-05-06 18:33:29 +00:00
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impl<T: Instance> RngCore for Random<T> {
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fn next_u32(&mut self) -> u32 {
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loop {
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let bits = unsafe { T::regs().sr().read() };
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if bits.drdy() {
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2021-05-09 23:19:07 +00:00
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return unsafe { T::regs().dr().read() };
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2021-05-06 18:33:29 +00:00
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}
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}
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}
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fn next_u64(&mut self) -> u64 {
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let mut rand = self.next_u32() as u64;
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rand |= (self.next_u32() as u64) << 32;
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rand
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}
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fn fill_bytes(&mut self, dest: &mut [u8]) {
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for chunk in dest.chunks_mut(4) {
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let rand = self.next_u32();
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for (slot, num) in chunk.iter_mut().zip(rand.to_be_bytes().iter()) {
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*slot = *num
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}
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}
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}
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fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand_core::Error> {
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2021-05-09 23:19:07 +00:00
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self.fill_bytes(dest);
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2021-05-06 18:33:29 +00:00
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Ok(())
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}
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}
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2021-05-09 23:19:07 +00:00
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impl<T: Instance> CryptoRng for Random<T> {}
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2021-05-06 18:33:29 +00:00
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impl<T: Instance> traits::rng::Rng for Random<T> {
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type Error = Error;
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2021-05-09 23:19:07 +00:00
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#[rustfmt::skip]
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2021-08-04 17:39:54 +00:00
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type RngFuture<'a> where Self: 'a = impl Future<Output=Result<(), Self::Error>> + 'a;
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2021-05-06 18:33:29 +00:00
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fn fill_bytes<'a>(&'a mut self, dest: &'a mut [u8]) -> Self::RngFuture<'a> {
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unsafe {
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T::regs().cr().modify(|reg| {
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reg.set_rngen(true);
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});
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}
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async move {
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for chunk in dest.chunks_mut(4) {
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2021-05-06 18:58:41 +00:00
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poll_fn(|cx| {
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RNG_WAKER.register(cx.waker());
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unsafe {
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T::regs().cr().modify(|reg| {
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reg.set_ie(true);
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});
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}
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let bits = unsafe { T::regs().sr().read() };
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if bits.drdy() {
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Poll::Ready(Ok(()))
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} else if bits.seis() {
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2021-05-06 20:38:53 +00:00
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self.reset();
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2021-05-06 18:58:41 +00:00
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Poll::Ready(Err(Error::SeedError))
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} else if bits.ceis() {
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2021-05-06 20:38:53 +00:00
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self.reset();
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2021-05-06 18:58:41 +00:00
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Poll::Ready(Err(Error::ClockError))
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} else {
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Poll::Pending
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}
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2021-05-09 23:19:07 +00:00
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})
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.await?;
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2021-05-06 18:33:29 +00:00
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let random_bytes = unsafe { T::regs().dr().read() }.to_be_bytes();
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for (dest, src) in chunk.iter_mut().zip(random_bytes.iter()) {
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*dest = *src
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}
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}
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Ok(())
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}
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2021-04-26 18:11:46 +00:00
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}
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2021-08-27 20:10:01 +00:00
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#[rustfmt::skip]
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type NextFuture<'a> where Self: 'a = impl Future<Output=Result<u32, Self::Error>> + 'a;
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fn next<'a>(&'a mut self, range: u32) -> Self::NextFuture<'a> {
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async move {
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let t = (-(range as i32) % (range as i32)) as u32;
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loop {
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let mut buf = [0; 4];
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traits::rng::Rng::fill_bytes(self, &mut buf).await?;
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let x = u32::from_le_bytes(buf);
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let m = x as u64 * range as u64;
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let l = m as u32;
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if l < t {
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continue;
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}
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return Ok((m >> 32) as u32);
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}
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}
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}
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2021-04-26 18:11:46 +00:00
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}
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pub(crate) mod sealed {
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use super::*;
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pub trait Instance {
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2021-05-06 18:33:29 +00:00
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fn regs() -> pac::rng::Rng;
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2021-04-26 18:11:46 +00:00
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}
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}
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2021-06-09 11:54:53 +00:00
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pub trait Instance: sealed::Instance + crate::rcc::RccPeripheral {}
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2021-04-26 18:11:46 +00:00
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2021-06-03 15:09:29 +00:00
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crate::pac::peripherals!(
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(rng, $inst:ident) => {
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impl Instance for peripherals::$inst {}
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impl sealed::Instance for peripherals::$inst {
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fn regs() -> crate::pac::rng::Rng {
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crate::pac::RNG
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}
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}
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};
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);
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macro_rules! irq {
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($irq:ident) => {
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mod rng_irq {
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use crate::interrupt;
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#[interrupt]
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unsafe fn $irq() {
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let bits = $crate::pac::RNG.sr().read();
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if bits.drdy() || bits.seis() || bits.ceis() {
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$crate::pac::RNG.cr().write(|reg| reg.set_ie(false));
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$crate::rng::RNG_WAKER.wake();
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}
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}
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}
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};
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}
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crate::pac::interrupts!(
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(RNG) => {
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irq!(RNG);
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};
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(RNG_LPUART1) => {
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irq!(RNG_LPUART1);
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};
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(AES_RNG_LPUART1) => {
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irq!(AES_RNG_LPUART1);
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};
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(AES_RNG) => {
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irq!(AES_RNG);
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};
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(HASH_RNG) => {
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irq!(HASH_RNG);
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};
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);
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