Start writing bare-metal stm32 kernel in rust

1 files changed, 61 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..a3e8071
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,61 @@
+#![no_main]
+#![no_std]
+
+use core::panic::PanicInfo;
+
+#[link_section = ".on_reset"]
+#[no_mangle]
+pub static __RESET_VECTOR: fn() -> ! = on_reset;
+
+#[no_mangle]
+pub static mut DEADBEEF: u32 = 0xdeadbeef;
+pub static mut OTHER: u32 = 0;
+
+/** Load into the data segments */
+pub fn load_data_segments() -> () {
+    extern "C" {
+        static mut __data_load: u32;
+        static mut __data_store_start: u32;
+        static mut __data_store_end: u32;
+        static mut __bss_start: u32;
+        static mut __bss_end: u32;
+    }
+
+    unsafe {
+        let mut data_load_addr: *mut u32 = &mut __data_load;
+        let mut store_cursor: *mut u32 = &mut __data_store_start;
+        let data_store_end_addr: *mut u32 = &mut __data_store_end;
+
+        while store_cursor < data_store_end_addr {
+            store_cursor.write_volatile(*data_load_addr);
+            data_load_addr = data_load_addr.offset(1);
+            store_cursor = store_cursor.offset(1);
+        }
+
+        let bss_end: *mut u32 = &mut __bss_end;
+        let mut bss_cursor: *mut u32 = &mut __bss_start;
+
+        while bss_cursor < bss_end {
+            bss_cursor.write_volatile(0);
+            bss_cursor = bss_cursor.offset(1);
+        }
+    }
+
+    return;
+}
+
+pub fn on_reset() -> ! {
+    load_data_segments();
+
+    unsafe {
+        DEADBEEF += 100;
+        OTHER = DEADBEEF;
+    }
+
+    loop {}
+}
+
+#[panic_handler]
+fn panic(_info: &PanicInfo) -> ! {
+    loop {}
+}