This code was unobfuscated. (see Listing8.txt)

  0x420899: 8B44240C       MOV      EAX,DWORD PTR [ESP+0xC]
  0x42089D: 33C9           XOR      ECX,ECX               
  0x42089F: 334804         XOR      ECX,DWORD PTR [EAX+0x4]
  0x4208A2: 334808         XOR      ECX,DWORD PTR [EAX+0x8]
  0x4208A5: 33480C         XOR      ECX,DWORD PTR [EAX+0xC]
  0x4208A8: 334810         XOR      ECX,DWORD PTR [EAX+0x10]
  0x4208AB: 8B642408       MOV      ESP,DWORD PTR [ESP+0x8]
  0x4208AF: 648F0500000000 POP      DWORD PTR FS:[0x0]    
  0x4208B6: 83C404         ADD      ESP,0x4               
  0x4208B9: 0F31           RDTSC                          
  0x4208BB: 2B0424         SUB      EAX,DWORD PTR [ESP]   
  0x4208BE: 83C404         ADD      ESP,0x4               
  0x4208C1: 3D78563412     CMP      EAX,0x12345678        
  0x4208C6: 7606           JBE      0x4208CE  
  0x4208C8: 5E             POP      ESI                   
  0x4208C9: C6460F01       MOV      BYTE PTR [ESI+0xF],0x1
  0x4208CD: 56             PUSH     ESI