title: What was CS register's value at boot time?
body: <p>I'm a green hand to assembly language. These days I used bochs to simulate the boot procedure from virtual floppy. But one thing I don't know is what the <code>CS</code> register value is when the system initializes. </p>
  
  <pre><code>;;  init registers
  
  org 0x7c00
  
  BaseOfStack equ 0x7c00
  
  Label_Start:
  
  mov ax, cs
  mov ds, ax
  mov es, ax
  mov ss, ax
  mov sp, BaseOfStack
  
  ;; clear screen
  
  mov ax, 0600h
  mov bx, 0700h
  mov cx, 0
  mov dx, 0184h
  int 10h
  </code></pre>
  
  <p>The above code is only part of it. When the <code>ORG</code> command was executed, what was the <code>CS</code> register value at the instruction <code>mov ax, cs</code>. Is it the same as <em>0x7c00</em>? Thanks.  </p>
  
  <p>Below is bochsrc configuration:</p>
  
  <pre><code>romimage: file="$BXSHARE/BIOS-bochs-latest"
  vgaromimage: file="$BXSHARE/VGABIOS-lgpl-latest"
  boot: floppy
  floppy_bootsig_check: disabled=0
  floppya: type=1_44, 1_44="myboot.img", status=inserted
  pci: enabled=1, chipset=i440fx
  vga: extension=vbe, update_freq=15
  cpu: ips=15000000
  log: bochsout.txt
  mouse: enabled=0
  megs: 32
  </code></pre>