Removed inline asm, bumped MSRV

Cargo.toml

@@ -15,10 +15,9 @@ version = "0.0.1"
 edition = "2018"
 
 [features]
-default = ["inline-asm", "jlink-quirks"]
-inline-asm = []
+default = ["jlink-quirks"]
 jlink-quirks = []
 no-semihosting = []
 
 [dependencies]
-riscv = "0.7.0"
+riscv = "0.8.0"

README.md

@@ -11,8 +11,8 @@ This project is developed and maintained by the [Cortex-M team][team].
 
 # Minimum Supported Rust Version (MSRV)
 
-This crate is guaranteed to compile on stable Rust 1.33.0 and up. It *might*
-compile with older versions but that may change in any new patch release.
+This crate is guaranteed to compile on stable Rust 1.59.0 and up. It **won't**
+compile with older versions.
 
 ## License
 

src/lib.rs

@@ -151,14 +151,6 @@
 //!
 //! # Optional features
 //!
-//! ## `inline-asm`
-//!
-//! When this feature is enabled semihosting is implemented using inline assembly (`llvm_asm!`) and
-//! compiling this crate requires nightly.
-//!
-//! When this feature is disabled semihosting is implemented using FFI calls into an external
-//! assembly file and compiling this crate works on stable and beta.
-//!
 //! ## `jlink-quirks`
 //!
 //! When this feature is enabled, return values above `0xfffffff0` from semihosting operation
@@ -179,10 +171,11 @@
 //!
 //! [pdf]: http://infocenter.arm.com/help/topic/com.arm.doc.dui0471e/DUI0471E_developing_for_arm_processors.pdf
 
-#![cfg_attr(feature = "inline-asm", feature(asm))]
 #![deny(missing_docs)]
 #![no_std]
 
+use core::arch::asm;
+
 #[macro_use]
 mod macros;
 
@@ -192,11 +185,6 @@ pub mod export;
 pub mod hio;
 pub mod nr;
 
-#[cfg(not(feature = "inline-asm"))]
-extern "C" {
-    fn __sh_syscall(nr: usize, arg: usize) -> usize;
-}
-
 /// Performs a semihosting operation, takes a pointer to an argument block
 #[inline(always)]
 pub unsafe fn syscall<T>(nr: usize, arg: &T) -> usize {
@@ -207,7 +195,7 @@ pub unsafe fn syscall<T>(nr: usize, arg: &T) -> usize {
 #[inline(always)]
 pub unsafe fn syscall1(_nr: usize, _arg: usize) -> usize {
     match () {
-        #[cfg(all(feature = "inline-asm", not(feature = "no-semihosting")))]
+        #[cfg(not(feature = "no-semihosting"))]
         () => {
             let mut nr = _nr;
             // The instructions below must always be uncompressed, otherwise