Get rid of nightly features by using ‘global_asm’.

Now compiles and runs on stable.

2 files changed, 14 insertions, 25 deletions

diff --git a/src/boot.S b/src/boot.S
new file mode 100644
index 0000000..d31e5fe
--- /dev/null
+++ b/src/boot.S
@@ -0,0 +1,11 @@
+        .global _start
+        .section .text.init
+_start:
+        .option push
+        .option norelax
+        la gp, __global_pointer$
+        .option pop
+        la sp, _stack_top
+
+        csrr a0, mhartid
+        tail main
diff --git a/src/main.rs b/src/main.rs
index c0d41d3..8d95d00 100755
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,11 +1,11 @@
-#![feature(naked_functions)]
-
 #![no_std]
 #![no_main]
 
-use core::arch::asm;
+use core::arch::global_asm;
 use gd32vf103_pac::Peripherals;
 
+global_asm!(include_str!("boot.S"));
+
 #[no_mangle]
 fn main(_hartid: usize) -> ! {
     // let peripherals = Peripherals::take().unwrap();
@@ -49,28 +49,6 @@ fn main(_hartid: usize) -> ! {
     }
 }
 
-#[naked]
-#[link_section = ".text.init"]
-#[export_name = "_start"]
-unsafe extern "C" fn _start() -> ! {
-    // At boot, the hart is in privilege mode M, mstatus fields MIE
-    // and MPRV are 0, the pc is set to a reset vector, the mcause
-    // register specifies why the reset occurred.
-    // c.f.: [^super::rism2] § 3.4 (Reset)
-    asm!(
-        ".option push",
-        ".option norelax",
-        "la gp, __global_pointer$",
-        ".option pop",
-
-        "csrr a0, mhartid",
-        "la sp, _stack_top",
-
-        "tail main",
-        options(noreturn)
-    )
-}
-
 #[panic_handler]
 fn panic(info: &core::panic::PanicInfo) -> ! {
     if let Some(loc) = info.location() {