Hi everyone.
I'm trying to convert an assembly code to its corresponding regular expression. I'm trying to match program patterns to discover anomalies. Being a novice in assembly language, i thought i would try to first convert a simple addition program to its corresponding expression before moving onto other code. Could someone please help me in this regard?
Do you either have the ASM code or the Regular Expression you're trying to create?
Do you either have the ASM code or the Regular Expression you're trying to create?
Not really. I just took the following program off the internet.
It adds 2 numbers and stores the result in a third variable. What i now need is a method to convert this into its corresponding regular expression. I do not have any matching regular expression to compare this with.
TITLE A04ASM1 (EXE) Move and add operations
; ---------------------------------------------
STACK SEGMENT PARA STACK 'Stack'
DW 32 DUP(0)
STACK ENDS
; ----------------------------------------------
DATASEG SEGMENT PARA 'Data'
FLDD DW 215
FLDE DW 125
FLDF DW ?
DATASEG ENDS
; -----------------------------------------------
CODESEG SEGMENT PARA 'Code'
MAIN PROC FAR
ASSUME SS:STACK,DS:DATASEG,CS:CODESEG
MOV AX,DATASEG ;Set address of data
MOV DS,AX ; segment in DS
MOV AX,FLDD ;Move 0215 to AX
ADD AX,FLDE ;Add 0125 to AX
MOV FLDF,AX ;Store sum in FLDF
MOV AX,4C00H ;End processing
INT 21H
MAIN ENDP ;End of procedure
CODESEG ENDS ;End of segment
END MAIN ;End of programNot really. I just took the following program off the internet.
It adds 2 numbers and stores the result in a third variable. What i now need is a method to convert this into its corresponding regular expression. I do not have any matching regular expression to compare this with.TITLE A04ASM1 (EXE) Move and add operations ; --------------------------------------------- STACK SEGMENT PARA STACK 'Stack' DW 32 DUP(0) STACK ENDS ; ---------------------------------------------- DATASEG SEGMENT PARA 'Data' FLDD DW 215 FLDE DW 125 FLDF DW ? DATASEG ENDS ; ----------------------------------------------- CODESEG SEGMENT PARA 'Code' MAIN PROC FAR ASSUME SS:STACK,DS:DATASEG,CS:CODESEG MOV AX,DATASEG ;Set address of data MOV DS,AX ; segment in DS MOV AX,FLDD ;Move 0215 to AX ADD AX,FLDE ;Add 0125 to AX MOV FLDF,AX ;Store sum in FLDF MOV AX,4C00H ;End processing INT 21H MAIN ENDP ;End of procedure CODESEG ENDS ;End of segment END MAIN ;End of program
Admins / Members,
Any suggestions on how I can proceed with this? I seem to be stuck. :(
I'm trying to truly understand how that piece of code would match a regular expression.
If that's what you truly mean.
When I saw the term regular expression, I was expecting you to need either:
1) Some ASM code that does pattern matching of a string (equivalent to a Regex)
2) A Regex that could substitute for ASM code that does pattern matching of a string.
Is this assumption incorrect?
I'm trying to truly understand how that piece of code would match a regular expression.
If that's what you truly mean.
When I saw the term regular expression, I was expecting you to need either:
1) Some ASM code that does pattern matching of a string (equivalent to a Regex)
2) A Regex that could substitute for ASM code that does pattern matching of a string.Is this assumption incorrect?
Sorry for the delayed response.
What i was looking for was to create a program that identifies the working of other programs. The asm i run should be able to verify the functionality of another program
for example if there are codes for addition, subtraction, multiplication, etc. the code i run should be able to identify if the input program is an addition program. This verification needs to be done using regular expression.
That could be a lot of code.
How much time do you have?
That could be a lot of code.
How much time do you have?
Yea.. I figured that a lot of code would be involved and i guess i have enough time. How much do you think i will need? And any suggestions on how to proceed with this?
Can you show me the regular expression you want to use to find a program that does addition?
Regular expressions are usually compared to strings.
Should I assume you are only going to look for the + character to determine it's an "addition" program?
How are you going to tell the difference between a minus - and a hyphen - ?
What i figured after a lot of thought was that the whole program boils down to how i'm going to read a program. I figured i'd temporarily get the input program source code and verify +,-,*,/ bounded by a string on either side. In that case the hyphen does not come into the picture. But the problem comes when the source code contains strings like ++,--, etc. in which case i am stumped.
Programs perform a lot of arithmetic in code, if reading human readable
source code check for an
abundance of these operators (+-*/) and () [] pairs, or look for red-tape
directives such as #include .include include .i386, to identify
the probability of the source-code being a valid program.
The thing is, I just have the program mnemonics. I need to find out the working of the program (ie.) what the program actually does and i need to do this using automated code. I thought i'd use a simple addition program as a test sample but it looks like it not simple at all. As suggested i checked it out on human readable code where "string + string" sequence implies addition program where the string is not a special character and it seems to work. But how can i check this for mnemonics? How do i even start this?
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