simplify boot.S

src/boot.S

@@ -1,33 +1,10 @@
-/*
-The linker script specifies _start as the entry point to the kernel and the
-bootloader will jump to this position once the kernel has been loaded. It
-doesn't make sense to return from this function as the bootloader is gone.
-*/
-.section .text
 .global hos_start
 .type hos_start, @function
 hos_start:
+    /* Set stack pointer. */
     mov $_stack_end, %esp
  
-    /*
-    This is a good place to initialize crucial processor state before the
-    high-level kernel is entered. It's best to minimize the early
-    environment where crucial features are offline. Note that the
-    processor is not fully initialized yet: Features such as floating
-    point instructions and instruction set extensions are not initialized
-    yet. The GDT should be loaded here. Paging should be enabled here.
-    C++ features such as global constructors and exceptions will require
-    runtime support to work as well.
-    */
-
-    /*
-    Enter the high-level kernel. The ABI requires the stack is 16-byte
-    aligned at the time of the call instruction (which afterwards pushes
-    the return pointer of size 4 bytes). The stack was originally 16-byte
-    aligned above and we've pushed a multiple of 16 bytes to the
-    stack since (pushed 0 bytes so far), so the alignment has thus been
-    preserved and the call is well defined.
-    */
+    /* Jump to C. */
     push $0
     push $0
     push $0