kernel/entry.s

   1 ; when our kernel source has functions before _start and we blindly transfer control to the beginning
   2 ; of the kernel binary, it will wrongly execute the other functions
   3 ; the solution is to link a small assembly routine (this) which executes a known label within the kernel
   4 ; so that this routine comes before the kernel in the resulting binary
   5 ; we cannot link the boot sector code and the kernel because the former needs to be a raw binary, while the
   6 ; kernel is compiled into an ELF object file which contains some metadata on the kernel code
   7
   8         bits 32 ; this is started in protected mode
   9         extern _start ; the known label in the kernel source we will execute is, well, not in this assembly routine
  10
  11         call _start ; call the known label
  12         jmp $ ; it should never return, but hang forever if it does