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pkedpker Master Cheater Reputation: 1
Joined: 11 Oct 2006 Posts: 412
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Posted: Fri Aug 22, 2008 3:07 am Post subject: |
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naw nop is no operaion is just ignores it.. its one opcode 0x90 why would it mean change eax? for it to change eax over eax it would need a total of 2 opcodes. the opcode for operation and opcode where 1 byte means 2 registers.
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hcavolsdsadgadsg I'm a spammer Reputation: 26
Joined: 11 Jun 2007 Posts: 5801
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Posted: Fri Aug 22, 2008 3:23 am Post subject: |
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pkedpker wrote: | it does do something it moves the edi back into the edi.. so it moves it self back to it self i think so but it does something doesn't do nothing.. it still processes the command now replacing it with nops will make it looks messier though.. like
mov edi, edi is like correct me im wrong but its like gonna be omg. like man lemme do this.. 2 NOPS! man.. thats heavy |
mov reg, reg is essentially a true 2 byte NOP, as it has no effect on the program other than moving EIP along.
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Symbol I'm a spammer Reputation: 0
Joined: 18 Apr 2007 Posts: 5094 Location: Israel.
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Posted: Fri Aug 22, 2008 3:26 am Post subject: |
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pkedpker wrote: | naw nop is no operaion is just ignores it.. its one opcode 0x90 why would it mean change eax? for it to change eax over eax it would need a total of 2 opcodes. the opcode for operation and opcode where 1 byte means 2 registers. |
"NOP" is an alias for "XCHG EAX,EAX", type "XCHG EAX,EAX" in any disassembler, ollydbg for example, and you'll see it'll write "0x90", but when it reads "0x90" it treats it as "NOP".
I made a disassembler not long ago, so I checked for xchg parameters, appearntly its only 1 byte. I thought there was a byte for "xchg reg" and for the other register.
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DoomsDay Grandmaster Cheater Reputation: 0
Joined: 06 Jan 2007 Posts: 768 Location: %HomePath%
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Posted: Fri Aug 22, 2008 3:48 am Post subject: |
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It does have, but its one byte encoding: Code: | XCHG - Exchange Register/Memory with Register
register1 with Register2 1000 011w: 11 reg1 reg2
AX or EAX with reg 1001 0 reg
memory with reg 1000 011w:mod reg r/m |
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sponge I'm a spammer Reputation: 1
Joined: 07 Nov 2006 Posts: 6009
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Posted: Fri Aug 22, 2008 3:55 am Post subject: |
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pkedpker wrote: | naw nop is no operaion is just ignores it.. its one opcode 0x90 why would it mean change eax? for it to change eax over eax it would need a total of 2 opcodes. the opcode for operation and opcode where 1 byte means 2 registers. | If nop really was no-operation, it wouldn't take 1 clock cycle. Your attitude is annoying; next time take the time to verify shit.
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pkedpker Master Cheater Reputation: 1
Joined: 11 Oct 2006 Posts: 412
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Posted: Fri Aug 22, 2008 5:08 pm Post subject: |
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first of all if you don't like what I write learn to ignore reading it.. English isn't my strong point as far as langauges go.. Most strong point is patterns math and finding connections and common sense..
Of course nop would take some power from CPU even if it is a No operation.. because after all cpu is the brains of the whole thing.. RAM can't just ignore nops.. it has to be processed threw a cpu. if even ram could posbbily somehow modify it self which it cant
its just data on paper letters on paper dont move man.
I try to explain things as basic as it could be.. but thing is.. all you try to do is flame me! atleast ignore me geez *sigh*
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WafflesFTW Expert Cheater Reputation: 0
Joined: 21 Mar 2008 Posts: 131
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Posted: Fri Aug 22, 2008 5:15 pm Post subject: |
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pkedpker wrote: | first of all if you don't like what I write learn to ignore reading it.. English isn't my strong point as far as langauges go.. Most strong point is patterns math and finding connections and common sense..
Of course nop would take some power from CPU even if it is a No operation.. because after all cpu is the brains of the whole thing.. RAM can't just ignore nops.. it has to be processed threw a cpu. if even ram could posbbily somehow modify it self which it cant
its just data on paper letters on paper dont move man.
I try to explain things as basic as it could be.. but thing is.. all you try to do is flame me! atleast ignore me geez *sigh* |
Because you are full of shit. Do you know what cout does? Can you code hello world yet?
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sponge I'm a spammer Reputation: 1
Joined: 07 Nov 2006 Posts: 6009
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Posted: Fri Aug 22, 2008 5:37 pm Post subject: |
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Funny how you IGNORE what people say. NOP = xchg eax, eax.
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igoticecream Grandmaster Cheater Supreme Reputation: 0
Joined: 23 Apr 2006 Posts: 1807 Location: 0x00400000
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Posted: Sat Aug 23, 2008 10:48 am Post subject: |
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Yes, Nop is an alias of xchg eax, eax
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blackmorpheus Expert Cheater Reputation: 0
Joined: 05 Apr 2008 Posts: 159
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Posted: Fri Oct 24, 2008 11:28 am Post subject: |
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What exactly is trampolining, and why do you have to do it?
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