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Index > Main > [solved] Xor qword

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AE



Joined: 07 Apr 2022
Posts: 29
AE
What would be the shortest way to implement such a pseudocode
Code:
xor rax, 7E7E7E7E7E7E7E7Eh    
Post 11 Apr 2022, 17:37
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ProMiNick



Joined: 24 Mar 2012
Posts: 671
Location: Russian Federation, Sochi
ProMiNick
if operand cannot be encoded as imm part of instruction fastest way to place it in initialized data:
Code:
format PE64 GUI
entry start

section '.text' code readable executable

  start:
        xor     rax,qword[xorpattern]

section '.data' data readable writeable

  xorpattern db 8 dup ($7E)    
Post 11 Apr 2022, 17:48
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 18622
Location: In your JS exploiting you and your system
revolution
You can do 64-bit loads into an unused register.
Code:
mov r8, 0x7E7E7E7E7E7E7E7E
xor rax, r8    
Post 11 Apr 2022, 20:05
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AE



Joined: 07 Apr 2022
Posts: 29
AE
Thanks! That's it.
Post 11 Apr 2022, 20:27
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