Crate voladdress

A crate for working with volatile addresses / memory mapped IO / MMIO.

Types here are only intended be used for values that can be read or written in a single machine instruction. Depending on your target, this generally means individual scalar values, or repr(transparent) wrappers around said values.

If the target data type of a VolAddress can’t be read in a single machine instruction then you can get unwanted data tearing.

If your data is a number of identical values in a row consider using VolBlock or VolSeries. If your data is irregular you may need to use a grab-bag of VolAddress entries or something like that.

Example

use voladdress::*;

// some examples for the GBA

// general read/write; safe, just has to be volatile
pub const MOSAIC: VolAddress<u16, Safe, Safe> =
  unsafe { VolAddress::new(0x0400_004C) };

// a read-only location
pub const VCOUNT: VolAddress<u8, Safe, ()> =
  unsafe { VolAddress::new(0x0400_0006) };

// a block of 256 entries
pub const BG_PALRAM: VolBlock<u16, Safe, Safe, 256> =
  unsafe { VolBlock::new(0x0500_0000) };

// address for a DMA transfer, unsafe to write, but safe to read
pub const DMA0_SRC: VolAddress<usize, Unsafe, Safe> =
  unsafe { VolAddress::new(0x0400_00B0) };

Structs

Safe	Lets you put “Safe” into a generic type parameter.
Unsafe	Lets you put “Unsafe” into a generic type parameter.
VolAddress	A volatile address.
VolBlock	A volatile memory block.
VolBlockIter	An iterator over a volatile block.
VolSeries	A volatile memory “series”.
VolSeriesIter	An iterator over a volatile series.