Add initial outline for bare-metal Rust day.

src/SUMMARY.md

@@ -233,6 +233,32 @@
 
 ----
 
+# Day 5A: Morning
+
+- [Welcome](welcome-no_std.md)
+- [`no_std`](no_std/no_std.md)
+  - [`core`]()
+  - [`alloc`]()
+- [Microcontrollers]()
+  - [PACs]()
+  - [HAL crates]()
+  - [The type state pattern]()
+
+# Day 5A: Afternoon
+
+- [Application processors]()
+  - [MMIO]()
+  - [Let's write a UART driver]()
+  - [Logging]()
+- [Useful crates]()
+  - [`zerocopy`]()
+  - [`aarch64_paging`]()
+  - [`buddy_system_allocator`]()
+  - [`tinyvec`]()
+  - [`spin` and `once_cell`]()
+
+---
+
 # Solutions
 
 ----

src/no_std/no_std.md

@@ -0,0 +1,39 @@
+# `no_std`
+
+## `core`
+
+* Slices, `&str`, `CStr`
+* `NonZeroU8`...
+* `Option`, `Result`
+* `Display`, `Debug`, `write!`...
+* `Iterator`
+* `panic!`, `assert_eq!`...
+* `NonNull` and all the usual pointer-related functions
+* `Future` and `async`/`await`
+* `fence`, `AtomicBool`, `AtomicPtr`, `AtomicU32`...
+* `Duration`
+
+## `alloc`
+
+* `Box`, `Cow`, `Arc`, `Rc`
+* `Vec`, `BinaryHeap`, `BtreeMap`, `LinkedList`, `VecDeque`
+* `String`, `CString`, `format!`
+
+## `std`
+
+* `Error`
+* `HashMap`
+* `Mutex`, `Condvar`, `Barrier`, `Once`, `RwLock`, `mpsc`
+* `File` and the rest of `fs`
+* `println!`, `Read`, `Write`, `Stdin`, `Stdout` and the rest of `io`
+* `Path`, `OsString`
+* `net`
+* `Command`, `Child`, `ExitCode`
+* `spawn`, `sleep` and the rest of `thread`
+* `SystemTime`, `Instant`
+
+<details>
+
+* `HashMap` depends on RNG.
+
+</details>

src/welcome-no_std.md

@@ -0,0 +1 @@
+# Welcome to `no_std`