.bin/cargo-card10

-#!/usr/bin/env bash
-
-set -e
-
-cargo build --release
-arm-none-eabi-objcopy -O binary target/thumbv7em-none-eabi/release/$2 card10.bin
-python c/bootloader/crc_patch.py card10.bin
-
-echo "Copy this file to the device in USB Mass Storage mode:"
-ls -l card10.bin

.gitlab-ci.yml

@@ -29,4 +29,5 @@ firmware:
       - apps
       - main.py
       - menu.py
+      - card10.cfg
     expire_in: 1 week

.gitmodules

-[submodule "c"]
-	path = c
+[submodule "card10-sys/firmware"]
+	path = card10-sys/firmware
 	url = https://git.card10.badge.events.ccc.de/card10/firmware.git

0001-feat-nix-add-jailbreak-arg.patch

-From 93c318a284f7b0f3bce2046e1f631599190eaa10 Mon Sep 17 00:00:00 2001
-From: Astro <astro@spaceboyz.net>
-Date: Fri, 23 Aug 2019 19:44:45 +0200
-Subject: [PATCH] feat(nix): add jailbreak arg
-
----
- default.nix | 12 ++++++++++--
- 1 file changed, 10 insertions(+), 2 deletions(-)
-
-diff --git a/default.nix b/default.nix
-index dc9649bc..c49d0ab2 100644
---- a/default.nix
-+++ b/default.nix
-@@ -1,4 +1,8 @@
--with import <nixpkgs> {};
-+{ pkgs ? import <nixpkgs> {},
-+  jailbreak ? false,
-+}:
-+
-+with pkgs;
- 
- let
-   py = python36;
-@@ -12,6 +16,10 @@ let
-       sha256 = "15nkx0pa4lskwin84flpk8fsw3jqg6wic6v3s83syjqg76h6my61";
-     };
-   };
-+  mesonOpt =
-+    if jailbreak
-+    then "-Djailbreak_card10=true"
-+    else "";
- in stdenv.mkDerivation rec {
-   name = "card10";
-   nativeBuildInputs = [
-@@ -39,7 +47,7 @@ in stdenv.mkDerivation rec {
-     done
- 
-     # Actually run the build.
--    meson --cross-file card10-cross.ini "$build"
-+    meson --cross-file card10-cross.ini ${mesonOpt} "$build"
-     ninja -C "$build" -j $NIX_BUILD_CORES
- 
-     # Copy ELFs for debugging
--- 
-2.22.0
-

0001-hack-epicardium-reduce-init-delay-from-2s-to-0.1s.patch

+From baef13b1adb6f7bf01a7dfd7f4f44a5a3e950b1d Mon Sep 17 00:00:00 2001
+From: Astro <astro@spaceboyz.net>
+Date: Thu, 5 Sep 2019 02:22:45 +0200
+Subject: [PATCH] hack(epicardium): reduce init delay from 2s to 0.1s
+
+---
+ epicardium/main.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/epicardium/main.c b/epicardium/main.c
+index 51edbe93..7607d39d 100644
+--- a/epicardium/main.c
++++ b/epicardium/main.c
+@@ -32,7 +32,7 @@ int main(void)
+ 	epic_disp_print(10, 20, "Epicardium", 0xfe20, 0x0000);
+ 	epic_disp_print(off > 0 ? off : 0, 40, version_buf, 0xfe20, 0x0000);
+ 	epic_disp_update();
+-	mxc_delay(2000000);
++	mxc_delay(100000);
+ 
+ 	LOG_DEBUG("startup", "Initializing tasks ...");
+ 
+-- 
+2.22.1
+

Cargo.toml

 [workspace]
 members = [
-  "l0dable",
+  "card10-sys",
+  "card10-alloc",
+  "card10-l0dable",
   "example",
   "rkanoid",
+  "draw-image",
 ]
+
 default-members = [
   "example",
   "rkanoid",
+  "draw-image",
 ]
 
 [profile.release]
@@ -16,3 +21,6 @@ debug = true
 opt-level = "s"
 lto = true
 panic = "abort"
+
+[patch.crates-io]
+alloc-cortex-m = { git = 'https://github.com/rust-embedded/alloc-cortex-m' }

README.md

 # Rust support for the card10 CCCamp19 badge
 
+## Prepare your card10
+
+**Jailbreaking is no longer necessary!**
+
+Starting with firmware v1.9, running ELF binaries requires a
+`/card10.cfg` with the following content:
+
+```
+execute_elf=true
+```
+
 ## Prebuilt binaries
 
 By courtesy of this Gitlab's CI system, and NixOS, we build `.elf`
 files for you drop into the `apps/` directory of your card10 badge.
 
-Because running ELF binaries requires a jailbroken base firmware
-starting with v1.5, we build this one too. It includes this project's
-Rust binaries.
+For each commit in this repository, we also build complete firmware
+images with the required configuration and our example binaries.
 
 https://git.card10.badge.events.ccc.de/astro/rust-card10/-/jobs
 
@@ -40,31 +50,65 @@ firmware including the matching libc.
    git submodule update --init --recursive
    ```
 
-## Setup a Rust enabled firmware
+## Build and run Rust loadables
 
-To allow rust based apps on card10 you need a firmware which allows
-to run custom elf binaries on the core. This requires a custom build
-with `-Djailbreak_card10=true` as bootstrapping flag.
+### Setup
 
-Assuming that you installed all required dependencies mentioned in
-https://firmware.card10.badge.events.ccc.de/how-to-build.html this
-should work as following:
+If you want to come up with your own rust based loadable crate a few
+preparations are required:
 
-```shell
-cd c/
-./bootstrap -Djailbreak_card10=true
-ninja -C build/
+  - Setup the new crate repository.
+ 
+  - Add `card10-l0dable = "^0.1"` as a dependency to your new crate.
+ 
+  - Change the configuration of the default cargo release profile inside your
+    `Cargo.toml` file:
+ 
+    ```
+    [profile.release]
+    opt-level = "s"
+    panic = "abort"
     ```
 
-And then copy `build/pycardium/pycardium_epicardium.bin` as
-`card10.bin` onto your badge.
+  - Create (or update) the `thumbv7em-none-eabi` target configuration at
+    `$PROJECT/.cargo/config` with the following rustflags:
  
-## Build and run Rust loadables
+    ```
+    [target.thumbv7em-none-eabi]
+    rustflags = [
+      "-C", "linker=arm-none-eabi-gcc",
+      "-C", "link-args=-Tl0dable.ld -n -pie -fPIC",
+      "-C", "relocation-model=pic",
+    ]
+
+    [build]
+    target = "thumbv7em-none-eabi"
+    ```
+
+  - Ensure that your crate is marked as a `non_std` project and make
+    `card10-l0dable` aware of your custom main function. This should require
+    the following update to your `main.rs` file.
+
+    ```main.rs
+    #![no_std]
+    #![no_main]
+
+    use card10_l0dable::main;
+
+    main!(main);
+    fn main() {}
+    ```
+
+### Compilation
+
+To compile the project use the nightly toolchain and define the proper target.
 
 ```shell
-cargo +nightly build --release --target thumbv7-none-eabi
+cargo +nightly build --release --target thumbv7em-none-eabi
 ```
 
+### Transfer to card10
+
 Then copy the resulting executable from the target directory 
 `target/thumbv7em-none-eabi/release/example` into the
 `apps` directory of your badge.
@@ -74,29 +118,32 @@ extension (e.g `example` must be renamed as `example.elf`).
 
 ## Crates
 
-| Crate    | Description                                               |
-| ----     | ---                                                       |
-| l0dable  | Helper crate for building l0dables                        |
-| example  | l0dable example                                           |
-| rkanoid  | Arkanoid clone                                            |
+| Crate          | Documentation             | Description                                      |
+| ----           | ---                       | ---                                              |
+| card10-sys     | [docs.rs][card10-sys]     | Unsafe C bindings for l0dables                   |
+| card10-alloc   | [docs.rs][card10-alloc]   | alloc::* support for l0dables                    |
+| card10-l0dable | [docs.rs][card10-l0dable] | High-level crate for building l0dables           |
+| example        |                           | l0dable example                                  |
+| rkanoid        |                           | Arkanoid clone                                   |
+| draw-image     |                           | Example of drawing a static image to the display |
+
+[card10-sys]: https://docs.rs/card10-sys/
+[card10-alloc]: https://docs.rs/card10-alloc/
+[card10-l0dable]: https://docs.rs/card10-l0dable/
 
 
 ## Misc
 
 ### How to update the firmware bindings
 
-1) Update the `c/` submodule to the latest firmware state.
+1) Update the `card10-sys/firmware` submodule to the latest firmware state.
 
 2) Rebuild the firmware as described above.
 
 3) Run the following script from the project root directory
 
    ```shell
-   python c/epicardium/api/genapi.py -H c/epicardium/epicardium.h -c l0dable/src/client.c -s l0dable/src/server.c
+   python card10-sys/firmware/epicardium/api/genapi.py -H card10-sys/firmware/epicardium/epicardium.h -c card10-sys/vendor/client.c -s card10-sys/vendor/server.c
    ```
 
 4) Rebuild your app :)
-
-## TODO
-
-- [ ] alloc

c @ c8dbb334

-Subproject commit c8dbb334d9bfb99ddf0e9daacbe8b3ab88b60ed6

l0dable/Cargo.toml → card10-alloc/Cargo.toml

 [package]
-edition = "2018"
-name = "card10-l0dable"
+
+name = "card10-alloc"
 version = "0.1.1"
-authors = ["Astro <astro@spaceboyz.net>", "Kloenk <me@kloenk.de>"]
+authors = ["Astro <astro@spaceboyz.net>"]
 license = "MIT/Apache-2.0"
+edition = "2018"
+
+description = "Dynamic memory allocation for card10 l0dables"
 repository = "https://git.card10.badge.events.ccc.de/astro/rust-card10"
 homepage = "https://git.card10.badge.events.ccc.de/astro/rust-card10"
+documentation = "https://docs.rs/card10-alloc"
+
+categories = ["no-std", "memory-management"]
 keywords = [
     "CCC",
     "CCCamp2019",
@@ -13,21 +19,7 @@ keywords = [
     "card10",
     "l0dable",
 ]
-categories = ["no-std"]
-description = """
-make l0dables for the Card10 (CCCamp 2019) badge
-"""
-include = [
-    "**/*.rs",
-    "Cargo.toml",
-    "l0dable.ld",
-    "../c/",
-]
 
 [dependencies]
-r0 = "0.2"
-panic-abort = "0.3"
-
-[build-dependencies]
-cc = "1.0"
-bindgen = "0.51"
+alloc-cortex-m = "0.3"
+card10-sys = { path = "../card10-sys" }

card10-alloc/src/lib.rs

+//! Support for dynamically allocated memory
+//!
+//! Reproduces l0dable hardware.c's `_sbrk()`
+//!
+//! Unfortunately, we cannot link `_sbrk()` directly because it
+//! references the unwieldy `errno`.
+//!
+//! ## Example
+//!
+//! ```rust
+//! #![no_std]
+//! #![no_main]
+//!
+//! extern crate alloc;
+//! use alloc::vec;
+//! use card10_l0dable::*;
+//!
+//! main!(main);
+//! fn main() {
+//!     // Pass stack headroom
+//!     card10_alloc::init(128 * 1024);
+//!     let mut xs = vec![];
+//!     xs.push(23);
+//! }
+//! ```
+#![no_std]
+#![feature(asm)]
+#![feature(alloc_error_handler)]
+
+use core::alloc::Layout;
+use alloc_cortex_m::CortexMHeap;
+use card10_sys as _;
+
+#[global_allocator]
+static ALLOCATOR: CortexMHeap = CortexMHeap::empty();
+
+extern "C" {
+    static mut __heap_start: u32;
+}
+
+#[inline(always)]
+fn sp() -> usize {
+    let mut value;
+    unsafe {
+        asm!("mov $0, sp" : "=r" (value) ::: "volatile");
+    }
+    value
+}
+
+/// Call this before using anything from `alloc`.
+///
+/// Consider the size of your stack-allocated variables for the
+/// `stack_headroom` parameter.
+///
+/// Returns heap size
+pub fn init(stack_headroom: usize) -> usize {
+    let start = unsafe { &__heap_start } as *const _ as usize;
+    let size = sp() - stack_headroom - start;
+    unsafe { ALLOCATOR.init(start, size); }
+    size
+}
+
+#[alloc_error_handler]
+fn on_oom(_layout: Layout) -> ! {
+    panic!("OOM")
+}

card10-l0dable/Cargo.toml

+[package]
+edition = "2018"
+name = "card10-l0dable"
+version = "0.3.0"
+authors = [
+    "Astro <astro@spaceboyz.net>",
+    "Kloenk <me@kloenk.de>",
+    "Bruno Kirschner <bruno.kirschner@online.de>",
+    "Puzzlewolf <camp@nora.pink>",
+    "Raphael Nestler <raphael.nestler@gmail.com>",
+    "Danilo Bargen <mail@dbrgn.ch>",
+    "toon <toon@c3d2.de>",
+    "Sergey Pepyakin <sergei@parity.io>",
+
+]
+license = "MIT/Apache-2.0"
+repository = "https://git.card10.badge.events.ccc.de/astro/rust-card10"
+homepage = "https://git.card10.badge.events.ccc.de/astro/rust-card10"
+keywords = [
+    "CCC",
+    "CCCamp2019",
+    "CCCamp19",
+    "card10",
+    "l0dable",
+]
+categories = ["no-std"]
+description = "make l0dables for the Card10 (CCCamp 2019) badge"
+documentation = "https://docs.rs/card10-l0dable"
+
+[dependencies]
+card10-sys = { path = "../card10-sys" }
+embedded-graphics = "0.5"

l0dable/src/bhi160.rs → card10-l0dable/src/bhi160.rs

+/// Accelerometer, Gyroscope, Orientation
+
 use core::{
     fmt::{self, Display, Write},
     marker::PhantomData,
     mem::MaybeUninit,
 };
 
-use crate::{bindings::*, errno};
+use card10_sys::*;
 
 pub trait SensorType {
     /// sensor_type in C, sensor_id in Python
@@ -12,6 +14,7 @@ pub trait SensorType {
     fn convert_single(value: i16) -> f32;
 }
 
+#[derive(Debug)]
 pub struct Accelerometer;
 impl SensorType for Accelerometer {
     fn sensor_type() -> u32 {
@@ -22,6 +25,7 @@ impl SensorType for Accelerometer {
     }
 }
 
+#[derive(Debug)]
 pub struct Gyroscope;
 impl SensorType for Gyroscope {
     fn sensor_type() -> u32 {
@@ -32,6 +36,7 @@ impl SensorType for Gyroscope {
     }
 }
 
+#[derive(Debug)]
 pub struct Orientation;
 impl SensorType for Orientation {
     fn sensor_type() -> u32 {
@@ -50,6 +55,10 @@ pub struct Sensor<S: SensorType> {
 }
 
 impl<S: SensorType> Sensor<S> {
+    /// Use one of:
+    /// - `BHI160::<Accelerometer>::start()`
+    /// - `BHI160::<Gyroscope>::start()`
+    /// - `BHI160::<Orientation>::start()`
     fn new(stream_id: i32) -> Self {
         Self {
             stream_id,
@@ -118,7 +127,7 @@ pub struct SensorData<S> {
 }
 
 impl<'a, S: SensorType> IntoIterator for &'a SensorData<S> {
-    type Item = SensorDataItem;
+    type Item = SensorDataItem<S>;
     type IntoIter = SensorDataIter<'a, S>;
 
     fn into_iter(self) -> Self::IntoIter {
@@ -132,25 +141,26 @@ pub struct SensorDataIter<'a, S> {
 }
 
 impl<'a, S: SensorType> Iterator for SensorDataIter<'a, S> {
-    type Item = SensorDataItem;
+    type Item = SensorDataItem<S>;
 
     fn next(&mut self) -> Option<Self::Item> {
         while self.pos < self.data.n {
-            self.pos += 1;
-
             let vec = &self.data.buf[self.pos];
             if vec.data_type != DATA_TYPE_VECTOR {
                 writeln!(crate::UART, "Sensor: skip type {}\r", vec.data_type).ok();
                 continue;
             }
 
-            let item = SensorDataItem {
-                x: S::convert_single(vec.x),
-                y: S::convert_single(vec.y),
-                z: S::convert_single(vec.z),
+            let item = SensorDataItem::<S> {
+                x_raw: vec.x,
+                y_raw: vec.y,
+                z_raw: vec.z,
                 status: vec.status,
+                _kind: PhantomData,
             };
 
+            self.pos += 1;
+
             return Some(item);
         }
 
@@ -159,11 +169,26 @@ impl<'a, S: SensorType> Iterator for SensorDataIter<'a, S> {
 }
 
 #[derive(Debug, Clone)]
-pub struct SensorDataItem {
-    x: f32,
-    y: f32,
-    z: f32,
-    status: u8,
+pub struct SensorDataItem<S: SensorType> {
+    pub x_raw: i16,
+    pub y_raw: i16,
+    pub z_raw: i16,
+    pub status: u8,
+    _kind: PhantomData<S>,
+}
+
+impl<S: SensorType> SensorDataItem<S> {
+    pub fn get_x(&self) -> f32 {
+        S::convert_single(self.x_raw)
+    }
+
+    pub fn get_y(&self) -> f32 {
+        S::convert_single(self.y_raw)
+    }
+
+    pub fn get_z(&self) -> f32 {
+        S::convert_single(self.z_raw)
+    }
 }
 
 #[repr(C)]

l0dable/src/bme680.rs → card10-l0dable/src/bme680.rs

+/// Enviromental sensor
+
+use card10_sys::*;
 use core::mem::uninitialized;
-use super::bindings::*;
 
 pub struct BME680;
 pub type SensorData = bme680_sensor_data;
@@ -7,7 +9,7 @@ pub type SensorData = bme680_sensor_data;
 impl BME680 {
     pub fn start() -> Self {
         if unsafe { epic_bme680_init() } != 0 {
-            panic!("Cannot start light sensor");
+            panic!("Cannot start BME680 sensor");
         }
         BME680
     }
@@ -24,6 +26,8 @@ impl BME680 {
 
 impl Drop for BME680 {
     fn drop(&mut self) {
-        unsafe { epic_bme680_deinit(); }
+        unsafe {
+            epic_bme680_deinit();
+        }
     }
 }

l0dable/src/buttons.rs → card10-l0dable/src/buttons.rs

-use super::bindings::*;
+use card10_sys::*;
 
+/// Button inputs
 pub struct Buttons {
     state: u32,
 }
 
 impl Buttons {
+    /// Read the current button state
     pub fn read() -> Self {
-        let mask =
-            epic_button_BUTTON_LEFT_BOTTOM |
-            epic_button_BUTTON_RIGHT_BOTTOM |
-            epic_button_BUTTON_LEFT_TOP |
-            epic_button_BUTTON_RIGHT_TOP |
-            epic_button_BUTTON_RESET;
+        let mask = epic_button_BUTTON_LEFT_BOTTOM
+            | epic_button_BUTTON_RIGHT_BOTTOM
+            | epic_button_BUTTON_LEFT_TOP
+            | epic_button_BUTTON_RIGHT_TOP
+            | epic_button_BUTTON_RESET;
         let state = unsafe { epic_buttons_read(mask as u8) }.into();
         Buttons { state }
     }

l0dable/src/display.rs → card10-l0dable/src/display.rs

-use super::bindings::*;
 use super::framebuffer::FrameBuffer;
+use card10_sys::*;
 
 #[derive(Debug, Clone, Copy)]
 #[repr(C)]
@@ -32,9 +32,7 @@ impl Color {
 
     pub fn rgb8(r8: u8, g8: u8, b8: u8) -> Self {
         let c =
-            ((u16::from(r8) & 0xF8) << 8) |
-            ((u16::from(g8) & 0xFA) << 3) |
-            (u16::from(b8) & 0xF8);
+            ((u16::from(r8) & 0xF8) << 8) | ((u16::from(g8) & 0xFA) << 3) | (u16::from(b8) & 0xF8);
         Color(c)
     }
 
@@ -51,7 +49,7 @@ impl Color {
     }
 
     pub fn g8(&self) -> u8 {
-        self.r() << 2
+        self.g() << 2
     }
 
     pub fn b(&self) -> u8 {
@@ -59,7 +57,7 @@ impl Color {
     }
 
     pub fn b8(&self) -> u8 {
-        self.r() << 3
+        self.b() << 3
     }
 }
 
@@ -77,63 +75,167 @@ pub enum FillStyle {
 
 pub struct Display;
 
+#[repr(u8)]
+pub enum Font {
+    Font8 = disp_font_name_DISP_FONT8 as u8,
+    Font12 = disp_font_name_DISP_FONT12 as u8,
+    Font16 = disp_font_name_DISP_FONT16 as u8,
+    Font20 = disp_font_name_DISP_FONT20 as u8,
+    Font24 = disp_font_name_DISP_FONT24 as u8,
+}
+
+/// Immediate mode routines
 impl Display {
-    pub const W: u16 = 160;
-    pub const H: u16 = 80;
-    pub const FONT_W: u16 = 14;
-    pub const FONT_H: u16 = 20;
+    pub const W: i16 = 160;
+    pub const H: i16 = 80;
+    pub const FONT_W: i16 = 14;
+    pub const FONT_H: i16 = 20;
 
+    /// Open the display, return an instance
     pub fn open() -> Self {
-        unsafe { epic_disp_open(); }
+        unsafe {
+            epic_disp_open();
+        }
         Display
     }
 
+    /// Write Epicardium's framebuffer to the display
     pub fn update(&self) {
-        unsafe { epic_disp_update(); }
+        unsafe {
+            epic_disp_update();
+        }
     }
 
+    /// Clear everything with a solid `color`
     pub fn clear(&self, color: Color) {
-        unsafe { epic_disp_clear(color.0); }
+        unsafe {
+            epic_disp_clear(color.0);
+        }
     }
 
+    /// Print text
+    ///
     /// s must be 0-terminated
-    pub fn print(&self, x: u16, y: u16, s: &[u8], fg: Color, bg: Color) {
+    pub fn print(&self, x: i16, y: i16, s: &[u8], fg: Color, bg: Color) {
         unsafe {
             epic_disp_print(x, y, s.as_ptr(), fg.0, bg.0);
         }
     }
 
-    pub fn pixel(&self, x: u16, y: u16, color: Color) {
+    /// Print text with a selected font
+    ///
+    /// s must be 0-terminated
+    pub fn print_adv(&self, font: Font, x: i16, y: i16, s: &[u8], fg: Color, bg: Color) {
+        unsafe {
+            epic_disp_print_adv(font as u8, x, y, s.as_ptr(), fg.0, bg.0);
+        }
+    }
+
+    /// Set a pixel
+    pub fn pixel(&self, x: i16, y: i16, color: Color) {
         unsafe {
             epic_disp_pixel(x, y, color.0);
         }
     }
 
-    pub fn line(&self, x1: u16, y1: u16, x2: u16, y2: u16, color: Color, linestyle: LineStyle, pixelsize: u16) {
+    /// Draw a line
+    pub fn line(
+        &self,
+        x1: i16,
+        y1: i16,
+        x2: i16,
+        y2: i16,
+        color: Color,
+        linestyle: LineStyle,
+        pixelsize: u16,
+    ) {
         unsafe {
             epic_disp_line(x1, y1, x2, y2, color.0, linestyle as u32, pixelsize);
         }
     }
 
-    pub fn rect(&self, x1: u16, y1: u16, x2: u16, y2: u16, color: Color, fillstyle: FillStyle, pixelsize: u16) {
+    pub fn rect(
+        &self,
+        x1: i16,
+        y1: i16,
+        x2: i16,
+        y2: i16,
+        color: Color,
+        fillstyle: FillStyle,
+        pixelsize: u16,
+    ) {
         unsafe {
             epic_disp_rect(x1, y1, x2, y2, color.0, fillstyle as u32, pixelsize);
         }
     }
 
-    pub fn circ(&self, x: u16, y: u16, rad: u16, color: Color, fillstyle: FillStyle, pixelsize: u16) {
+    /// Draw a circle
+    pub fn circ(
+        &self,
+        x: i16,
+        y: i16,
+        rad: u16,
+        color: Color,
+        fillstyle: FillStyle,
+        pixelsize: u16,
+    ) {
         unsafe {
             epic_disp_circ(x, y, rad, color.0, fillstyle as u32, pixelsize);
         }
     }
 
-    pub fn framebuffer<'d>(&'d self) -> FrameBuffer<'d> {
+    /// Obtain a handle for a framebuffer.
+    ///
+    /// Don't use `display.send()` but `framebuffer.send()` as long as
+    /// it is in use.
+    pub fn framebuffer<'d>(&'d mut self) -> FrameBuffer<'d> {
         FrameBuffer::uninitialized(self)
     }
 }
 
 impl Drop for Display {
     fn drop(&mut self) {
-        unsafe { epic_disp_close(); }
-    }
+        unsafe {
+            epic_disp_close();
+        }
+    }
+}
+
+/// Convenience text display
+///
+/// Requires `card10_alloc::init()` and `extern crate alloc;`
+#[macro_export]
+macro_rules! display {
+    ($disp: expr, $x: expr, $y: expr, $fg: expr, $bg: expr,
+     $fmt: expr) => ({
+         use alloc::format;
+         let s = format!(concat!($fmt, "\0"));
+         $disp.print($x, $y, s.as_bytes(), $fg, $bg);
+    });
+    ($disp: expr, $x: expr, $y: expr, $fg: expr, $bg: expr,
+     $fmt: expr, $($arg: tt)*) => ({
+         use alloc::format;
+         let s = format!(concat!($fmt, "\0"), $($arg)*);
+         $disp.print($x, $y, s.as_bytes(), $fg, $bg);
+    });
+}
+
+/// Convenience text display with selected font
+///
+/// Requires `card10_alloc::init()` and `extern crate alloc;`
+#[macro_export]
+macro_rules! display_adv {
+    ($disp: expr, $font: tt, $x: expr, $y: expr, $fg: expr, $bg: expr,
+     $fmt: expr) => ({
+         use alloc::format;
+         use card10_l0dable::Font;
+         let s = format!(concat!($fmt, "\0"));
+         $disp.print_adv(Font::$font, $x, $y, s.as_bytes(), $fg, $bg);
+    });
+    ($disp: expr, $font: tt, $x: expr, $y: expr, $fg: expr, $bg: expr,
+     $fmt: expr, $($arg: tt)*) => ({
+         use alloc::format;
+         let s = format!(concat!($fmt, "\0"), $($arg)*);
+         $disp.print_adv(Font::$font, $x, $y, s.as_bytes(), $fg, $bg);
+    });
 }

l0dable/src/fmt_buffer.rs → card10-l0dable/src/fmt_buffer.rs

@@ -37,7 +37,7 @@ impl<'a> fmt::Write for FmtBuffer<'a> {
     }
 }
 
-/// 256 bytes ought to be enough for any string
+/// 255 bytes ought to be enough for any C string
 pub fn str_to_cstr(s: &str) -> [u8; 256] {
     let mut buf: [u8; 256] = unsafe { uninitialized() };
     let mut fmt = FmtBuffer::new(buf.as_mut());