Registers and Variables

[dromenox]

Using this UDF, how do I save the value of a register in a variable? 

 

 

With C ++ do so: 

 

int variable; 
__asm mov variable, eax;

 

[trancexx]

eax will be the return value of the procedure, so that's easy.

Which register?

[dromenox]

eax will be the return value of the procedure, so that's easy.

Which register?

Any register

[dromenox]

I created this function, but it only works the first time I call.

[Danyfirex]

I think maybe something like this:

#Include "FASM.au3"
Opt("MustDeclareVars", 1)

; Initial a FASM object
Global $Fasm = FasmInit()

ConsoleWrite("AutoIt Embedded Flat Assembler (v" & FasmGetVersion() & ") Demo" & @CRLF)

; Demo 1: Using Parameters
    FasmReset($Fasm)
    FasmAdd($Fasm, "use32")
    FasmAdd($Fasm, "org " & FasmGetBasePtr($Fasm))
    FasmAdd($Fasm, "mov ebx, 10")
    FasmAdd($Fasm, "mov ecx, 40")
   Local $t= Registro("ebx,ecx")

ConsoleWrite($t.ebx & @CRLF)
ConsoleWrite($t.ecx & @CRLF)
FasmExit($Fasm)

Exit

Func Registro($reg)
Local $tStructure=DllStructCreate("DWORD ebx;DWORD ecx")
Local $pt=DllStructGetPtr($tStructure)
Local $split=StringSplit($reg,",")
FasmAdd($Fasm, "mov [" & $pt & "],"  & $split[1])
FasmAdd($Fasm, "mov [" & $pt+4 & "],"  & $split[2])
FasmAdd($Fasm, "ret")
ConsoleWrite(String(FasmGetBinary($Fasm)) & @CRLF)
Local $Ret = MemoryFuncCall("int", FasmGetFuncPtr($Fasm))
Return $tStructure

EndFunc

Saludos

[LarsJ]

dromenox, "Any register"? Do you mean this and this?

[dromenox]

dromenox, "Any register"? Do you mean this and this?

Yes, mainly EAX, EBX, ECX, EDX, ESI, EIP, EBP

[Danyfirex]

Well this is my try:

Edited...

expandcollapse popup

; ------------------------------------------------------------------
; The Embedded Flat Assembler 1.69 UDF Demo (2011.6.4)
; Purpose: Demonstrate the usage of embedded flat assembler
; Author:  Ward
; ------------------------------------------------------------------

#Include "FASM.au3"
#include <WinAPI.au3>
#include <Array.au3>
Opt("MustDeclareVars", 1)


;Strings For printf
Global Enum $eax,$ecx,$edx,$ebx,$esp,$ebp,$esi,$edi
Global $aRegistro[8]=["eax","ecx","edx","ebx","esp","ebp","esi","edi"]
Global $tStrings[8]
Global $pStrings[8]

CreateStructuresAndPointer()

;Get printf Funtion pointer
Global $hModule = _WinAPI_GetModuleHandle("msvcrt.dll")

If $hModule Then
    Global $pFunction = _WinAPI_GetProcAddress($hModule, "printf")
    ConsoleWrite("The address of the function is " & $pFunction & @CRLF)
EndIf



;Start Assembly
Global $Fasm = FasmInit()

ConsoleWrite("AutoIt Embedded Flat Assembler (v" & FasmGetVersion() & ") Demo" & @CRLF)
    FasmReset($Fasm)
    FasmAdd($Fasm, "use32")
    FasmAdd($Fasm, "org " & FasmGetBasePtr($Fasm))
    FasmAdd($Fasm, "mov ebx, 10")
    FasmAdd($Fasm, "mov ecx, 40")
    ;Debug
    Debug($ebx)
    Debug($ecx)
    Debug($edx)
    Debug($esp)
    Debug($ebp)
    Debug($eax)
    Debug($esi)
    Debug($edi)
    ;End Debug
    FasmAdd($Fasm, "mov eax, 100")
    FasmAdd($Fasm, "mov ecx, 100")
    FasmAdd($Fasm, "add ecx, eax")
    ;Debug
    Debug($eax)
    Debug($ecx)
    ;EndDebug
    FasmAdd($Fasm, "ret")
    ConsoleWrite(String(FasmGetBinary($Fasm)) & @CRLF)
    Local $Ret = MemoryFuncCall("int", FasmGetFuncPtr($Fasm))
    MsgBox(0,"",$Ret[0])
   FasmExit($Fasm)

Exit

;Function Debug
Func Debug($eReg)
FasmAdd($Fasm, "pushad")
FasmAdd($Fasm, "push " & $aRegistro[$eReg])
FasmAdd($Fasm, "push " & $pStrings[$eReg])
FasmAdd($Fasm, "call " & $pFunction)
FasmAdd($Fasm, "add esp,8")
FasmAdd($Fasm, "popad")
EndFunc

;Create Strings Structures and Pointer Function
Func CreateStructuresAndPointer()
Local $sString=""
for $i=0 to 8-1
    $sString="!Register " & $aRegistro[$i] & " Value: %d" & chr(10) & chr(0)
    $tStrings[$i]=DllStructCreate("char[" & Stringlen($sString)+1 & "]")
    $pStrings[$i]=DllStructGetPtr($tStrings[$i])
    DllStructSetData($tStrings[$i],1,$sString)
Next
EndFunc
 

Salida:

Saludos

Edited August 24, 2014 by Danyfirex

[trancexx]

I can't see any smart reason for this, unless it's for learning. In that case, you can use some online assembler (like this one) and generate opcodes yourself. Then you can write something like this:

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#include <Memory.au3>

If @AutoItX64 Then Exit MsgBox(4096, "Bzzz...", "x86 instructions below!" & @CRLF & "Re-run script with 32-bit interpretter.")

; allocation of executable space
$tCodeBuffer = _allocate_512_bytes_of_executable_code_and_get_it_to_me_as_dllstruct()

; write opcodes now:

;========================== eax = 778 ==============================
DllStructSetData($tCodeBuffer, 1, _
        "0x" & _
        "B8" & swap_endian(778) & _             ; mov eax, 778
        "C3") ; ret

$iVar = DllCallAddress("int", DllStructGetPtr($tCodeBuffer))[0]

ConsoleWrite("eax = " & $iVar & @CRLF)
;===================================================================

;========================== ecx = 122 ==============================
DllStructSetData($tCodeBuffer, 1, _
        "0x" & _
        "B9" & swap_endian(122) & _             ; mov ecx, 122
        "89C8" & _                              ; mov eax, ecx
        "C3") ; ret

$iVar = DllCallAddress("int", DllStructGetPtr($tCodeBuffer))[0]

ConsoleWrite("ecx = " & $iVar & @CRLF)
;===================================================================

;========================== edx = 77692 ============================
DllStructSetData($tCodeBuffer, 1, _
        "0x" & _
        "BA" & swap_endian(77692) & _           ; mov edx, 77692
        "89D0" & _                              ; mov eax, edx
        "C3") ; ret

$iVar = DllCallAddress("int", DllStructGetPtr($tCodeBuffer))[0]

ConsoleWrite("edx = " & $iVar & @CRLF)
;===================================================================

;========================== ebx = 234445 ===========================
DllStructSetData($tCodeBuffer, 1, _
        "0x" & _
        "BB" & swap_endian(234445) & _          ; mov ebx, 234445
        "89D8" & _                              ; mov eax, ebx (8BC3)
        "C3") ; ret

$iVar = DllCallAddress("int", DllStructGetPtr($tCodeBuffer))[0]

ConsoleWrite("ebx = " & $iVar & @CRLF)
;===================================================================

;========================== esi = 9123 =============================
DllStructSetData($tCodeBuffer, 1, _
        "0x" & _
        "BE" & swap_endian(9123) & _            ; mov esi, 9123
        "89F0" & _                              ; mov eax, esi
        "C3") ; ret

$iVar = DllCallAddress("int", DllStructGetPtr($tCodeBuffer))[0]

ConsoleWrite("esi = " & $iVar & @CRLF)
;===================================================================

;========================== edi = 43 ===============================
DllStructSetData($tCodeBuffer, 1, _
        "0x" & _
        "BF" & swap_endian(43) & _              ; mov edi, 43
        "89F8" & _                              ; mov eax, edi
        "C3") ; ret

$iVar = DllCallAddress("int", DllStructGetPtr($tCodeBuffer))[0]

ConsoleWrite("edi = " & $iVar & @CRLF)
;===================================================================

;...etc
; normally you would free exe buffer when not needed any more (omited here just because)


; few helper functions
Func _allocate_512_bytes_of_executable_code_and_get_it_to_me_as_dllstruct()
    Return DllStructCreate("byte[512]", _MemVirtualAlloc(0, 512, $MEM_COMMIT, $PAGE_EXECUTE_READWRITE))
EndFunc
Func swap_endian($iValue)
    Return Hex(BinaryMid($iValue, 1, 4))
EndFunc