Update linux-bootstrap-3.md

Booting/linux-bootstrap-3.md

@@ -515,7 +515,25 @@ It takes two parameters:
 
 Let's look inside `protected_mode_jump`. As I wrote above, you can find it in `arch/x86/boot/pmjump.S`. The first parameter will be in the `eax` register and the second one is in `edx`.
 
-First of all, we put the address of `boot_params` in the `esi` register and the address of the code segment register `cs` in `bx`. After this, we shift `bx` by 4 bits and add it to the memory location labeled `2` (which is `(cs << 4) + in_pm32`, the physical address to jump after transitioned to 32-bit mode) and jump to label `1`. So after this `in_pm32` in label `2` will be overwritten with `(cs << 4) + in_pm32`.
+First of all, we put the address of `boot_params` in the `esi` register and the address of the code segment register `cs` in `bx`. 
+
+```assembly
+GLOBAL(protected_mode_jump)
+	movl	%edx, %esi	# Pointer to boot_params table
+
+	xorl	%ebx, %ebx
+	movw	%cs, %bx
+```
+
+After this, we shift `bx` by 4 bits and add it to the memory location labeled `2` (which is `(cs << 4) + in_pm32`, the physical address to jump after transitioned to 32-bit mode) and jump to label `1`. 
+
+```assembly
+	shll	$4, %ebx
+	addl	%ebx, 2f 	# Add %ebx to the value stored at label 2
+	jmp	1f		# Short jump to serialize on 386/486
+```
+
+So after this `in_pm32` in label `2` will be overwritten with `(cs << 4) + in_pm32`.
 
 Next we put the data segment and the task state segment in the `cx` and `di` registers with: