Anyone recognise this routine, or can give a summery of it's function.

I have a routine which is called regularly in one client, but not in another... it's confusing the operation of the one where it is used, and I'm getting lost in it's logic. I believe it's a standard MS VC RT static routine, though I could be wrong... I have no idea what it is supposed to be doing though.

Here is the routine:-

Code:

MOV EDX,DWORD PTR SS:[ARG.3] MOV ECX,DWORD PTR SS:[ARG.1] TEST EDX,EDX ; Cascaded IF (cases 0..3, 3 exits) JE SHORT Jump1 XOR EAX,EAX MOV AL,BYTE PTR SS:[ARG.2] PUSH EDI MOV EDI,ECX CMP EDX,4 JB SHORT Jump2 NEG ECX ; Default case of cascaded IF AND ECX,00000003 JE SHORT Jump3 SUB EDX,ECX Jump4: MOV BYTE PTR DS:[EDI],AL ADD EDI,1 SUB ECX,1 JNE SHORT Jump4 Jump3: MOV ECX,EAX SHL EAX,8 ADD EAX,ECX MOV ECX,EAX SHL EAX,10 ADD EAX,ECX MOV ECX,EDX AND EDX,00000003 SHR ECX,2 JE SHORT Jump2 REP STOS DWORD PTR ES:[EDI] TEST EDX,EDX JE SHORT Jump5 Jump2: MOV BYTE PTR DS:[EDI],AL ; Cases 1, 2, 3 of cascaded IF ADD EDI,1 SUB EDX,1 JNE SHORT Jump2 Jump5: MOV EAX,DWORD PTR SS:[ARG.1] POP EDI RETN Jump1: MOV EAX,DWORD PTR SS:[ARG.1] ; Case 0 of cascaded RETN

I know it's a long shot, and I may be better off asking in a RCE forum, but if someone here has seen this logic in a client and made sense of it, or knows it from MSVC I'd be very greatful if you could untie the knotts in my brain right now.:lol: