Update to upstreamed avr rust

README.md

@@ -38,38 +38,26 @@ able to compile this crate. Also, because of some remaining bugs in
 the LLVM AVR backend, Rust's stock `libcore` cannot be compiled yet;
 we need to use Xargo to link to a slightly stripped down version.
 
-## 1. Build branch of LLVM with AVR support + kludges
+## 1. Install the Rust nightly compiler and the rust-src rustup component
 
-```
-$ git clone -b avr-rust-demo https://github.com/avr-rust/llvm.git llvm-avr
-$ mkdir -p build/llvm
-$ cd build/llvm
-$ cmake ../../llvm-avr -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=AVR -DLLVM_TARGETS_TO_BUILD=X86
-$ make
-$ cd ../...
-```
+Install [rustup](https://rustup.rs/).
 
-## 2. Build branch of `rustc` with AVR support
+Then install the Rust nightly compiler, and then add the `rust-src` component to Rustup.
 
-```
-$ git clone -b avr-support https://github.com/avr-rust/rust.git rust-avr
-$ mkdir -p build/rust
-$ cd build/rust
-$ ../../rust-avr/configure --llvm-root=$(realpath ../llvm)
-$ make
-$ cd ../..
+```bash
+# add the rust-src component which is used for building libcore
+rustup component add rust-src
 ```
 
-## 3. Register freshly-built Rust AVR toolchain with `rustup` (needed to work around [a Xargo bug][xargo-rustup])
+## 2. Enable the nightly compiler by default with `rustup`
 
-```
-$ rustup toolchain link avr-toolchain $(realpath build/rust/build/x86_64-unknown-linux-gnu/stage1
-$ rustup default avr-toolchain
+```bash
+$ rustup default nightly
 ```
 
-## 4. Build `chip8-avr` and all its dependencies using Xargo
+## 3. Build `chip8-avr` and all its dependencies using Xargo
 
-```
+```bash
 $ git clone https://github.com/gergoerdi/rust-avr-chip8-avr chip8-avr
 $ cd chip8-avr
 $ sh build.sh

avr-atmega328p.json

@@ -3,16 +3,18 @@
   "cpu": "atmega328p",
   "target-endian": "little",
   "target-pointer-width": "16",
+  "target-c-int-width": "16",
   "os": "unknown",
   "target-env": "",
   "target-vendor": "unknown",
   "arch": "avr",
-  "data-layout": "e-p:16:8-i8:8-i16:8-i32:8-i64:8-f32:8-f64:8-n8-a:8",
+  "data-layout": "e-P1-p:16:8-i8:8-i16:8-i32:8-i64:8-f32:8-f64:8-n8-a:8",
 
   "executables": true,
 
   "linker": "avr-gcc",
   "linker-flavor": "gcc",
+  "eh-frame-header": false,
   "pre-link-args": {
     "gcc": ["-Os", "-mmcu=atmega328p", "-T", "lookup-text.ld"]
   },

build.sh

@@ -1,3 +1,3 @@
 sh roms.sh
-XARGO_RUST_SRC=/ xargo build --target=avr-atmega328p --release $@
+cargo build -Z build-std=core --target=avr-atmega328p.json --release $@
 

src/keypad.rs

@@ -27,7 +27,7 @@ pub fn scan_key_row(row: u8) -> u8 {
             _ => {}
         };
 
-        asm!("NOP");
+        llvm_asm!("NOP");
 
         let mut result = 0;
         let mut buf = 0;

src/main.rs

@@ -1,5 +1,5 @@
 #![feature(lang_items)]
-#![feature(asm)]
+#![feature(llvm_asm)]
 #![feature(abi_avr_interrupt)]
 #![feature(unwind_attributes)]
 #![feature(core_intrinsics)]
@@ -18,10 +18,9 @@ pub mod std {
     pub unsafe extern "C" fn rust_eh_personality(state: (), exception_object: *mut (), context: *mut ()) -> () {
     }
 
-    #[lang = "panic_fmt"]
-    #[unwind]
-    pub extern fn rust_begin_panic(msg: (), file: &'static str, line: u32) -> ! {
-        loop{}
+    #[panic_handler]
+    fn panic(info: &core::panic::PanicInfo) -> ! {
+        loop { }
     }
 }
 

src/serial_ram.rs

@@ -21,7 +21,7 @@ pub fn setup() {
 #[inline(never)]
 pub fn write_ram(addr: u16, value: u8) {
     unsafe {
-        asm!("CLI");
+        llvm_asm!("CLI");
 
         volatile_store(PORTD, volatile_load(PORTD) & !(1 << 6));
         spi::sync(0x02);
@@ -30,14 +30,14 @@ pub fn write_ram(addr: u16, value: u8) {
         spi::sync(value);
         volatile_store(PORTD, volatile_load(PORTD) | (1 << 6));
 
-        asm!("SEI");
+        llvm_asm!("SEI");
     }
 }
 
 #[inline(never)]
 pub fn read_ram(addr: u16) -> u8 {
     unsafe {
-        asm!("CLI");
+        llvm_asm!("CLI");
 
         volatile_store(PORTD, volatile_load(PORTD) & !(1 << 6));
         spi::sync(0x03);
@@ -46,7 +46,7 @@ pub fn read_ram(addr: u16) -> u8 {
         let value = spi::sync(0);
         volatile_store(PORTD, volatile_load(PORTD) | (1 << 6));
 
-        asm!("SEI");
+        llvm_asm!("SEI");
 
         value
     }

src/timer.rs

@@ -15,7 +15,7 @@ pub fn setup() {
         volatile_store(TIMSK1, volatile_load(TIMSK1) | 1 << 1);
 
         // Good to go!
-        asm!("SEI")
+        llvm_asm!("SEI")
     }
 }
 
@@ -44,7 +44,7 @@ pub fn sleep_ms(duration_ms: u16) {
     while outer < duration_ms {
         let mut inner = 0;
         while inner < INNER_LOOP_ITERATIONS {
-            unsafe { asm!(""); }
+            unsafe { llvm_asm!(""); }
             inner += 1;
         }
         outer += 1;