Add support for asm!()

Cargo.toml

@@ -59,3 +59,6 @@ cfg-if = "0.1.10"
 path = "macros/"
 version = "=0.3.2"
 optional = true
+
+[build-dependencies]
+rustversion = "1.0"

README.md

@@ -32,7 +32,7 @@ The version on `crates.io` is pre-built.  The following is only necessary when t
 You need to have [atdf2svd][] (= 0.3.1), [svd2rust][] (= 0.19), [form][] (>= 0.8), [rustfmt][](for the *nightly* toolchain) and [svdtools][] (>= 0.1.9) installed:
 ```bash
 cargo install atdf2svd --version 0.3.1
-cargo install svd2rust --version 0.19
+cargo install svd2rust --version 0.19.0
 cargo install form
 rustup component add --toolchain nightly rustfmt
 pip3 install --user svdtools

build.rs

@@ -0,0 +1,16 @@
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+
+    maybe_enable_asm();
+}
+
+#[rustversion::before(1.59.0)]
+fn maybe_enable_asm() {
+    //
+}
+
+#[rustversion::since(1.59.0)]
+fn maybe_enable_asm() {
+    // https://github.com/rust-lang/rust/pull/92816
+    println!("cargo:rustc-cfg=avr_device_asm_macro");
+}

src/asm.rs

@@ -1,10 +1,15 @@
 //! Assembly instructions
 
+#[cfg(all(target_arch = "avr", avr_device_asm_macro))]
+use core::arch::asm;
+
 /// No Operation
 #[inline(always)]
 pub fn nop() {
     cfg_if::cfg_if! {
-        if #[cfg(target_arch = "avr")] {
+        if #[cfg(all(target_arch = "avr", avr_device_asm_macro))] {
+            unsafe { asm!("nop") }
+        } else if #[cfg(target_arch = "avr")] {
             unsafe { llvm_asm!("nop") }
         } else {
             unimplemented!()
@@ -16,7 +21,9 @@ pub fn nop() {
 #[inline(always)]
 pub fn sleep() {
     cfg_if::cfg_if! {
-        if #[cfg(target_arch = "avr")] {
+        if #[cfg(all(target_arch = "avr", avr_device_asm_macro))] {
+            unsafe { asm!("sleep") }
+        } else if #[cfg(target_arch = "avr")] {
             unsafe { llvm_asm!("sleep") }
         } else {
             unimplemented!()
@@ -28,7 +35,9 @@ pub fn sleep() {
 #[inline(always)]
 pub fn wdr() {
     cfg_if::cfg_if! {
-        if #[cfg(target_arch = "avr")] {
+        if #[cfg(all(target_arch = "avr", avr_device_asm_macro))] {
+            unsafe { asm!("wdr") }
+        } else if #[cfg(target_arch = "avr")] {
             unsafe { llvm_asm!("wdr") }
         } else {
             unimplemented!()

src/interrupt.rs

@@ -10,13 +10,31 @@
 
 pub use bare_metal::{CriticalSection, Mutex, Nr};
 
+#[cfg(all(target_arch = "avr", avr_device_asm_macro))]
+use core::arch::asm;
+
 #[inline]
 /// Disables all interrupts
 ///
 /// Returns a bool, reflecting whether interrupts were enabled prior to calling this method.
 pub fn disable() -> bool {
     cfg_if::cfg_if! {
-        if #[cfg(target_arch = "avr")] {
+        if #[cfg(all(target_arch = "avr", avr_device_asm_macro))] {
+            // Store current state
+            let sreg: u8;
+
+            unsafe {
+                asm!(
+                    "in {sreg}, 0x3F",
+                    sreg = out(reg) sreg,
+                )
+            };
+
+            // Disable interrupts
+            unsafe { asm!("cli") };
+
+            sreg & 0x80 == 0x80
+        } else if #[cfg(target_arch = "avr")] {
             // Store current state
             let sreg: u8;
             unsafe { llvm_asm!("in $0,0x3F" :"=r"(sreg) ::: "volatile") };
@@ -39,7 +57,9 @@ pub fn disable() -> bool {
 /// - Do not call this function inside an [crate::interrupt::free] critical section
 pub unsafe fn enable() {
     cfg_if::cfg_if! {
-        if #[cfg(target_arch = "avr")] {
+        if #[cfg(all(target_arch = "avr", avr_device_asm_macro))] {
+            asm!("sei");
+        } else if #[cfg(target_arch = "avr")] {
             llvm_asm!("sei" :::: "volatile");
         } else {
             unimplemented!()

src/lib.rs

@@ -56,7 +56,8 @@
 //! * `attiny861`
 //! * `attiny88`
 #![no_std]
-#![feature(llvm_asm)]
+#![cfg_attr(avr_device_asm_macro, feature(asm_experimental_arch))]
+#![cfg_attr(not(avr_device_asm_macro), feature(llvm_asm))]
 
 pub mod asm;
 pub mod interrupt;
@@ -167,10 +168,10 @@ pub use crate::devices::atmega644;
 pub use crate::devices::atmega8;
 #[cfg(feature = "atmega8u2")]
 pub use crate::devices::atmega8u2;
-#[cfg(feature = "attiny167")]
-pub use crate::devices::attiny167;
 #[cfg(feature = "attiny1614")]
 pub use crate::devices::attiny1614;
+#[cfg(feature = "attiny167")]
+pub use crate::devices::attiny167;
 #[cfg(feature = "attiny202")]
 pub use crate::devices::attiny202;
 #[cfg(feature = "attiny2313")]