root/initcode.S

/*   */

   1 # Initial process execs /init.
   2 # This code runs in user space.
   3 
   4 #include "syscall.h"
   5 #include "traps.h"
   6 
   7 
   8 # exec(init, argv)
   9 .globl start
  10 start:
  11   pushl $argv
  12   pushl $init
  13   pushl $0  // where caller pc would be
  14   movl $SYS_exec, %eax
  15   int $T_SYSCALL
  16 
  17 # for(;;) exit();
  18 exit:
  19   movl $SYS_exit, %eax
  20   int $T_SYSCALL
  21   jmp exit
  22 
  23 # char init[] = "/init\0";
  24 init:
  25   .string "/init\0"
  26 
  27 # char *argv[] = { init, 0 };
  28 .p2align 2
  29 argv:
  30   .long init
  31   .long 0
  32 

/*   */