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/// § 32.8.7.2
/// Address of the Data Buffer.
///
/// Offset: 0x00 & 0x10
/// Reset: 0xxxxxxxxx
/// Property: NA
#[derive(Clone, Copy, Debug)]
#[repr(C, packed)]
pub(crate) struct Addr(u32);
pub(crate) struct R {
bits: u32,
}
pub(crate) struct W {
bits: u32,
}
impl Addr {
pub fn read(&self) -> R {
R { bits: self.0 }
}
pub fn write<F>(&mut self, f: F)
where
F: FnOnce(&mut W) -> &mut W,
{
let mut w = W { bits: self.0 };
f(&mut w);
self.0 = w.bits;
}
pub fn modify<F>(&mut self, f: F)
where
for<'w> F: FnOnce(&R, &'w mut W) -> &'w mut W,
{
let r = R { bits: self.0 };
let mut w = W { bits: self.0 };
f(&r, &mut w);
self.0 = w.bits;
}
}
impl From<u32> for Addr {
fn from(v: u32) -> Self {
Self(v)
}
}
impl R {
/// Value in raw bits.
pub fn bits(&self) -> u32 {
self.bits
}
pub fn addr(&self) -> AddrR {
AddrR(self.bits)
}
}
/// Data Pointer Address Value
///
/// These bits define the data pointer address as an absolute double
/// word address in RAM. The two least significant bits must be zero
/// to ensure the descriptor is 32-bit aligned.
pub(crate) struct AddrR(u32);
impl AddrR {
pub fn bits(&self) -> u32 {
self.0
}
}
impl W {
/// Write raw bits.
pub unsafe fn bits(&mut self, v: u32) -> &mut Self {
self.bits = v;
self
}
pub fn addr(&mut self) -> AddrW {
AddrW { w: self }
}
}
pub(crate) struct AddrW<'a> {
w: &'a mut W,
}
impl<'a> AddrW<'a> {
pub unsafe fn bits(self, v: u32) -> &'a mut W {
// Address must be 32-bit aligned. cf §32.8.7.2 of SAMD21 data
// sheet.
assert!((v & 0x3) == 0);
self.w.bits = v;
self.w
}
// TODO: "safe" method take a pointer instead of raw u32
}
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