entry.S

//一部省略
.globl _start
_start = V2P_WO(entry)

.globl wait_main
wait_main:
  .long 0
# Entering xv6 on boot processor, with paging off.
.globl entry
entry:
  #Set Data Segment
  mov $0x10,%ax
  mov %ax,%ds
  mov %ax,%es
  mov %ax,%ss
  mov $0,%ax
  mov %ax,%fs
  mov %ax,%gs

  #Turn off paing
  movl %cr0,%eax
  andl $0x7fffffff,%eax
  movl %eax,%cr0 

  #Set Page Table Base Address
  movl    $(V2P_WO(entrypgdir)), %eax
  movl    %eax, %cr3
  
  #Disable IA32e mode
  movl $0x0c0000080,%ecx
  rdmsr
  andl $0xFFFFFEFF,%eax
  wrmsr

  # Turn on page size extension for 4Mbyte pages
  movl    %cr4, %eax
  orl     $(CR4_PSE), %eax
  andl    $0xFFFFFFDF, %eax
  movl    %eax, %cr4

  #Turn on Paging
  movl    %cr0, %eax
  orl     $0x80010001, %eax
  movl    %eax, %cr0




  # Set up the stack pointer.
  movl $(stack + KSTACKSIZE), %esp
  # Jump to main(), and switch to executing at
  # high addresses. The indirect call is needed because
  # the assembler produces a PC-relative instruction
  # for a direct jump.
#  jz .waiting_main
  movl $main, %edx
  jmp %edx

.comm stack, KSTACKSIZE