Fix rsp segfault, incorrect prologue

Author: kiwiyou

scripts/gen.py

@@ -8,8 +8,14 @@
     sys.exit(1)
 
 with open(binary_path, "rb") as f:
-    # remove prologue
-    code = f.read()[4:]
+    code = f.read()
+
+# remove prologue
+i = 0
+for i, byte in enumerate(code):
+    if byte not in range(0x50, 0x58) and byte != 0x41:
+        break
+code = code[i:]
 
 rem = len(code) % 8
 if rem:

src/codegen.rs

@@ -9,6 +9,9 @@ static ALLOC: allocator::Allocator = allocator::Allocator;
 #[no_mangle]
 #[link_section = ".init"]
 fn _start() -> ! {
+    unsafe {
+        asm!("and rsp, 0xFFFFFFFFFFFFFFF0", options(nomem));
+    }
     solution::main();
     unsafe {
         asm!("syscall", in("rax") 231, in("rdi") 0, options(nomem, noreturn));

src/io.rs

@@ -728,4 +728,3 @@ impl<const N: usize> Writer<N> {
         self.write(unsafe { MaybeUninit::slice_assume_init_ref(&buf[offset..]) });
     }
 }
-