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> Compiler Internals > More-than-one-byte NOPs.Goto page Previous 1, 2 |
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Teehee 11 Jun 2011, 14:19
i dont got it.
Whats the difference betwen using NOPs and another thing to simulate a nop? _________________ Sorry if bad english. |
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11 Jun 2011, 14:19 |
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Teehee 11 Jun 2011, 14:43
gotcha
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11 Jun 2011, 14:43 |
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CandyMan 24 Apr 2012, 22:11
use this macro:
Code: macro align value { virtual align value ..align = $ - $$ end virtual virtual at 0 lea eax,[dword 0] ..bitness = $ end virtual if ..bitness = 6 ;use32 times ..align/8 \ db $3E,$8D,$B4,$26,$00,$00,$00,$00 ;lea esi,[ds:esi*1+$00000000] ..align = ..align mod 8 if ..align = 7 db $8D,$B4,$26,$00,$00,$00,$00 ;lea esi,[esi*1+$00000000] else if ..align = 6 db $8D,$B6,$00,$00,$00,$00 ;lea esi,[esi+$00000000] else if ..align = 5 db $3E,$8D,$74,$26,$00 ;lea esi,[ds:esi+$00] else if ..align = 4 db $8D,$74,$26,$00 ;lea esi,[esi+$00] else if ..align = 3 db $8D,$76,$00 ;lea esi,[esi+$00] else if ..align = 2 db $89,$F6 ;mov esi,esi else if ..align = 1 db $90 ;nop end if else if ..bitness = 7 ;use64 times ..align/8 \ db $48,$8D,$B4,$26,$00,$00,$00,$00 ;lea rsi,[rsi*1+$00000000] ..align = ..align mod 8 if ..align = 7 db $48,$8D,$B6,$00,$00,$00,$00 ;lea rsi,[rsi+$00000000] else if ..align = 6 db $66,$48,$8D,$74,$26,$00 ;lea rsi,[rsi+$00] else if ..align = 5 db $48,$8D,$74,$26,$00 ;lea rsi,[rsi+$00] else if ..align = 4 db $48,$8D,$76,$00 ;lea rsi,[rsi+$00] else if ..align = 3 db $48,$89,$F6 ;mov rsi,rsi else if ..align = 2 db $40,$90 ;rex,nop else if ..align = 1 db $90 ;nop end if else ;use16 times ..align/8 \ db $8D,$B4,$00,$00,$8D,$B4,$00,$00 ;lea si,[si+$0000];lea si,[si+$0000] ..align = ..align mod 8 if ..align = 7 db $8D,$B4,$00,$00,$8D,$74,$00 ;lea si,[si+$0000];lea si,[si+$00] else if ..align = 6 db $8D,$B4,$00,$00,$89,$F6 ;lea si,[si+$0000];mov si,si else if ..align = 5 db $3E,$8D,$B4,$00,$00 ;lea si,[ds:si+$0000] else if ..align = 4 db $8D,$B4,$00,$00 ;lea si,[si+$0000] else if ..align = 3 db $8D,$74,$00 ;lea si,[si+$00] else if ..align = 2 db $89,$F6 ;mov si,si else if ..align = 1 db $90 ;nop end if end if } Test: use16 nop align 32 use32 nop align 32 use64 nop align 32 |
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24 Apr 2012, 22:11 |
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TrDr.Charlie 26 Apr 2012, 13:55
Code: ;********************************************************************************************************* ;* * ;* Results from my Intel Pentium(R) Dual-Core, T4400 @ 2.20 GHz * ;* * ;* !!!! Tested in 64-bit mode * ;* * ;********************************************************************************************************* ; Opcode(s) Dynamic ; Latency ; (in Ticks) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// db 1 dup ( 90h ) ; 0.1584, Opcode(s) : 90 db 2 dup ( 90h ) ; 0.7084, Opcode(s) : 90 90 db 3 dup ( 90h ) ; 1.2584, Opcode(s) : 90 90 90 db 4 dup ( 90h ) ; 1.8722, Opcode(s) : 90 90 90 90 db 5 dup ( 90h ) ; 2.4827, Opcode(s) : 90 90 90 90 90 db 6 dup ( 90h ) ; 3.0943, Opcode(s) : 90 90 90 90 90 90 db 7 dup ( 90h ) ; 3.7048, Opcode(s) : 90 90 90 90 90 90 90 db 8 dup ( 90h ) ; 4.3164, Opcode(s) : 90 90 90 90 90 90 90 90 db 9 dup ( 90h ) ; 4.9269, Opcode(s) : 90 90 90 90 90 90 90 90 90 db 10 dup ( 90h ) ; 5.5363, Opcode(s) : 90 90 90 90 90 90 90 90 90 90 db 11 dup ( 90h ) ; 6.1468, Opcode(s) : 90 90 90 90 90 90 90 90 90 90 90 db 12 dup ( 90h ) ; 6.7606, Opcode(s) : 90 90 90 90 90 90 90 90 90 90 90 90 db 13 dup ( 90h ) ; 7.3711, Opcode(s) : 90 90 90 90 90 90 90 90 90 90 90 90 90 db 14 dup ( 90h ) ; 7.9827, Opcode(s) : 90 90 90 90 90 90 90 90 90 90 90 90 90 90 db 15 dup ( 90h ) ; 8.5932, Opcode(s) : 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 ;///////////////////////////////////////////////////////////////////////////////////////////////////////// ; Opcode(s) Dynamic ; Latency ; (in Ticks) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// db 1 dup ( 66h ), 90h ; 0.1804, Opcode(s) : 66 90 db 2 dup ( 66h ), 90h ; 0.1804, Opcode(s) : 66 66 90 db 3 dup ( 66h ), 90h ; 0.1826, Opcode(s) : 66 66 66 90 db 4 dup ( 66h ), 90h ; 0.3652, Opcode(s) : 66 66 66 66 90 db 5 dup ( 66h ), 90h ; 0.3652, Opcode(s) : 66 66 66 66 66 90 db 6 dup ( 66h ), 90h ; 0.3894, Opcode(s) : 66 66 66 66 66 66 90 db 7 dup ( 66h ), 90h ; 0.5731, Opcode(s) : 66 66 66 66 66 66 66 90 db 8 dup ( 66h ), 90h ; 0.5731, Opcode(s) : 66 66 66 66 66 66 66 66 90 db 9 dup ( 66h ), 90h ; 0.7535, Opcode(s) : 66 66 66 66 66 66 66 66 66 90 db 10 dup ( 66h ), 90h ; 0.7535, Opcode(s) : 66 66 66 66 66 66 66 66 66 66 90 db 11 dup ( 66h ), 90h ; 0.9394, Opcode(s) : 66 66 66 66 66 66 66 66 66 66 66 90 db 12 dup ( 66h ), 90h ; 1.1231, Opcode(s) : 66 66 66 66 66 66 66 66 66 66 66 66 90 db 13 dup ( 66h ), 90h ; 1.1231, Opcode(s) : 66 66 66 66 66 66 66 66 66 66 66 66 66 90 db 14 dup ( 66h ), 90h ; 1.3057, Opcode(s) : 66 66 66 66 66 66 66 66 66 66 66 66 66 66 90 ;///////////////////////////////////////////////////////////////////////////////////////////////////////// ; Opcode(s) Dynamic ; Latency ; (in Ticks) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// db 7 dup ( 66h ), 90h ; 1.3057, Opcode(s) : 66 66 66 66 66 66 66 90 66 66 66 66 66 66 90 db 6 dup ( 66h ), 90h ; db 4 dup ( 66h ), 90h ; 1.3057, Opcode(s) : 66 66 66 66 90 66 66 66 66 90 66 66 66 66 90 db 4 dup ( 66h ), 90h ; db 4 dup ( 66h ), 90h ; db 3 dup ( 66h ), 90h ; 1.8722, Opcode(s) : 66 66 66 90 66 66 66 90 66 66 66 90 66 66 90 db 3 dup ( 66h ), 90h ; db 3 dup ( 66h ), 90h ; db 2 dup ( 66h ), 90h ; ;///////////////////////////////////////////////////////////////////////////////////////////////////////// ; Opcode(s) Dynamic ; Latency ; (in Ticks) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// db $EB, 0 ; 1.6247, Opcode(s) : EB 00 ; jmp $ + 2 db $E9, 0, 0, 0, 0 ; 1.6269, Opcode(s) : E9 00 00 00 00 ; jmp $ + 5 ;///////////////////////////////////////////////////////////////////////////////////////////////////////// ; Opcode(s) Dynamic ; Latency ; (in Ticks) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// db $87, $C0 ; 4.0392, Opcode(s) : 87 C0 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ; xchg eax, eax db $89, $C0 ; 1.1033, Opcode(s) : 89 C0 ; mov eax, eax db $8B, $c0 ; 1.1033, Opcode(s) : 8B C0 ; mov eax, eax ;///////////////////////////////////////////////////////////////////////////////////////////////////////// ; Opcode(s) Dynamic ; Latency ; (in Ticks) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// db $66, $8D, $04, $05, $00, $00, $00, $00 ; 5.4758, Opcode(s) : 66 8D 04 05 00 00 00 00 !!!!!!!!!!!!!!!!!!!! ; lea ax, [1*rax + 00000000h] ( in 64-bit mode it is rax ) db $8D, $04, $05, $00, $00, $00, $00 ; 1.0769, Opcode(s) : 8D 04 05 00 00 00 00 ; lea eax, [1*rax + 00000000h] ( in 64-bit mode it is rax ) db $8D, $80, $00, $00, $00, $00 ; 1.0769, Opcode(s) : 8D 80 00 00 00 00 ; lea eax, [rax + 00000000h] ( in 64-bit mode it is rax ) ;--------------------------------------------------------------------------------------------------------- db $66, $8D, $54, $22, $00 ; 5.4758, Opcode(s) : 66 8D 54 22 00 !!!!!!!!!!!!!!!!!!!!!!!!!!!!! ; lea dx, [rdx + 0] ( in 64-bit mode it is rdx ) db $66, $8D, $44, $20, $00 ; 5.4758, Opcode(s) : 66 8D 44 20 00 !!!!!!!!!!!!!!!!!!!!!!!!!!!!! ; lea ax, [rax + 0] ( in 64-bit mode it is rax ) ; ; !!!!!!!!!!!!! in 64-bit mode ; db $67, $8D, $54, $22, $00 ; 2.4057, Opcode(s) : 67 8D 54 22 00 !!!!!!!!!!!!!!!!!!!!!!!!!!!!! ; lea edx, [edx + 0] ( in 64-bit mode it is edx ) db $67, $8D, $44, $20, $00 ; 2.4057, Opcode(s) : 67 8D 44 20 00 !!!!!!!!!!!!!!!!!!!!!!!!!!!!! ; lea eax, [eax + 0] ( in 64-bit mode it is eax ) ;--------------------------------------------------------------------------------------------------------- db $8D, $44, $20, $00 ; 1.0769, Opcode(s) : 8D 44 20 00 ; lea eax, [rax + 0] ( in 64-bit mode it is rax ) db $8D, $40, $00 ; 1.0747, Opcode(s) : 8D 40 00 ; lea eax, [rax + 0] ( in 64-bit mode it is rax ) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// ; Opcode(s) Dynamic ; Latency ; (in Ticks) ;///////////////////////////////////////////////////////////////////////////////////////////////////////// ; ; !!!!!!!!!!!!! used (e.g.) in my ntoskrnl.exe ; db 0Fh, 1Fh, 00 ; 1.2584, Opcode(s) : 0F 1F 00 ; nop [rax] db 0Fh, 1Fh, 04h, 00 ; 1.2606, Opcode(s) : 0F 1F 04 00 ; nop [rax + 1*rax] db 66h, 0Fh, 1Fh, 04h, 00 ; 1.2606, Opcode(s) : 66 0F 1F 04 00 ; nop [rax + 1*rax] ;********************************************************************************************************* ;* * ;* For now all * ;* * ;********************************************************************************************************* |
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26 Apr 2012, 13:55 |
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