Merge pull request #204 from bjorn3/new_asm_for_0_9

Use new inline assembly syntax for the 0.9 series

src/e820.s

@@ -51,4 +51,5 @@ do_e820:
 	stc			# "function unsupported" error exit
 	ret
 
+.global mmap_ent
 mmap_ent: .word 0

src/main.rs

@@ -1,6 +1,6 @@
 #![feature(lang_items)]
 #![feature(global_asm)]
-#![feature(llvm_asm)]
+#![feature(asm)]
 #![no_std]
 #![no_main]
 
@@ -10,6 +10,7 @@ compile_error!("The bootloader crate must be compiled for the `x86_64-bootloader
 extern crate rlibc;
 
 use bootloader::bootinfo::{BootInfo, FrameRange};
+use core::arch::asm;
 use core::{arch::global_asm, convert::TryInto, panic::PanicInfo};
 use core::{mem, slice};
 use fixedvec::alloc_stack;
@@ -41,8 +42,8 @@ global_asm!(include_str!("video_mode/vga_320x200.s"));
 global_asm!(include_str!("video_mode/vga_text_80x25.s"));
 
 unsafe fn context_switch(boot_info: VirtAddr, entry_point: VirtAddr, stack_pointer: VirtAddr) -> ! {
-    llvm_asm!("call $1; ${:private}.spin.${:uid}: jmp ${:private}.spin.${:uid}" ::
-         "{rsp}"(stack_pointer), "r"(entry_point), "{rdi}"(boot_info) :: "intel");
+    asm!("mov rsp, {1}; call {0}; 2: jmp 2b",
+         in(reg) entry_point.as_u64(), in(reg) stack_pointer.as_u64(), in("rdi") boot_info.as_u64());
     ::core::hint::unreachable_unchecked()
 }
 
@@ -87,8 +88,12 @@ extern "C" {
 #[no_mangle]
 pub unsafe extern "C" fn stage_4() -> ! {
     // Set stack segment
-    llvm_asm!("mov bx, 0x0
-          mov ss, bx" ::: "bx" : "intel");
+    asm!(
+        "push rbx
+          mov bx, 0x0
+          mov ss, bx
+          pop rbx"
+    );
 
     let kernel_start = 0x400000;
     let kernel_size = &_kernel_size as *const _ as u64;