bu/load.S

   1 #define ASM_FILE 1
   2 #include <multiboot.h>
   3 #define EXT_C(func)                    func
   4 #define STACK_SIZE                     0x4000
   5 #define MULTIBOOT_HEADER_FLAGS         0x00000003
   6
   7 .text
   8 .global start,_start
   9
  10 start:
  11  _start:
  12         jmp     multiboot_entry
  13         .align  4
  14
  15 multiboot_header:
  16         .long   MULTIBOOT_HEADER_MAGIC
  17         .long   MULTIBOOT_HEADER_FLAGS
  18         .long   -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
  19
  20 multiboot_entry:
  21         movl    $(stack + STACK_SIZE), %esp
  22         pushl   $0
  23         popf
  24         pushl   %ebx
  25         pushl   %eax
  26
  27         call    EXT_C(cstart)
  28
  29 loop:
  30         hlt
  31         jmp    loop
  32
  33
  34 .comm   stack, STACK_SIZE