1 files changed, 80 insertions, 0 deletions
diff --git a/library/std/src/sys/pal/vexos/mod.rs b/library/std/src/sys/pal/vexos/mod.rs
new file mode 100644
index 00000000000..61a34b0f68a
--- /dev/null
+++ b/library/std/src/sys/pal/vexos/mod.rs
@@ -0,0 +1,80 @@
+#[path = "../unsupported/os.rs"]
+pub mod os;
+#[path = "../unsupported/pipe.rs"]
+pub mod pipe;
+pub mod time;
+
+#[expect(dead_code)]
+#[path = "../unsupported/common.rs"]
+mod unsupported_common;
+
+pub use unsupported_common::{
+    decode_error_kind, init, is_interrupted, unsupported, unsupported_err,
+};
+
+use crate::arch::global_asm;
+use crate::ptr;
+use crate::sys::stdio;
+use crate::time::{Duration, Instant};
+
+global_asm!(
+    r#"
+    .section .boot, "ax"
+    .global _boot
+
+    _boot:
+        ldr sp, =__stack_top @ Set up the user stack.
+        b _start             @ Jump to the Rust entrypoint.
+    "#
+);
+
+#[cfg(not(test))]
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn _start() -> ! {
+    unsafe extern "C" {
+        static mut __bss_start: u8;
+        static mut __bss_end: u8;
+
+        fn main() -> i32;
+    }
+
+    // Clear the .bss (uninitialized statics) section by filling it with zeroes.
+    // This is required, since the compiler assumes it will be zeroed on first access.
+    ptr::write_bytes(
+        &raw mut __bss_start,
+        0,
+        (&raw mut __bss_end).offset_from_unsigned(&raw mut __bss_start),
+    );
+
+    main();
+
+    cleanup();
+    abort_internal()
+}
+
+// SAFETY: must be called only once during runtime cleanup.
+// NOTE: this is not guaranteed to run, for example when the program aborts.
+pub unsafe fn cleanup() {
+    let exit_time = Instant::now();
+    const FLUSH_TIMEOUT: Duration = Duration::from_millis(15);
+
+    // Force the serial buffer to flush
+    while exit_time.elapsed() < FLUSH_TIMEOUT {
+        vex_sdk::vexTasksRun();
+
+        // If the buffer has been fully flushed, exit the loop
+        if vex_sdk::vexSerialWriteFree(stdio::STDIO_CHANNEL) == (stdio::STDOUT_BUF_SIZE as i32) {
+            break;
+        }
+    }
+}
+
+pub fn abort_internal() -> ! {
+    unsafe {
+        vex_sdk::vexSystemExitRequest();
+
+        loop {
+            vex_sdk::vexTasksRun();
+        }
+    }
+}