COM_UnMunge2 written in x64/x86 ASM

com_munge2.asm

;64 bit verison
proc INETWorker_Munge buf, len, npacket
	mov r13d, r8d
	xor eax, eax
	not r13d
	shr edx, 2 ;div 4
	jz @f
	.loop:
		and al, 0x3F
		mov r15d, [rcx]
		mov r12d, [IW_mungeTable + eax]
		xor r15d, r13d
		bswap r15d
		xor r15d, r12d
		xor r15d, r8d
		add eax, 4
		mov [rcx], r15d
		add ecx, 4
		dec edx
		jnz .loop
	@@:
	ret
endp

;64 bit version
proc INETWorker_UnMunge buf, len, npacket
	mov r13d, r8d
	xor eax, eax
	not r13d
	shr edx, 2 ;div 4
	jz @f
	.loop:
		and al, 0x3F
		mov r15d, [rcx]
		mov r12d, [IW_mungeTable + eax]
		xor r15d, r8d
		bswap r15d
		xor r15d, r12d
		xor r15d, r13d
		add eax, 4
		mov [rcx], r15d
		add ecx, 4
		dec edx
		jnz .loop
	@@:
	ret
endp

;32 bit version
proc INETWorker_UnMunge uses ebx esi edi, buf, len, npacket
	mov ebx, [npacket]
	mov esi, [buf]
	xor eax, eax
	not ebx
	shr [len], 2 ;div 4
	jz @f
	.loop:
		and al, 0x3F
		mov ecx, [esi]
		xor ecx, [npacket]
		bswap ecx
		xor ecx, [IW_mungeTable + eax]
		xor ecx, ebx
		add al, 4
		mov [esi], ecx
		add esi, 4
		dec [len]
		jnz .loop
	@@:
	ret
endp

IW_mungeTable:
	dd 0xFFFFE7A5, 0xBFEFFFE5, 0xFFBFEFFF, 0xBFEFBFED
	dd 0xBFAFEFBF, 0xFFBFAFEF, 0xFFEFBFAD, 0xFFFFEFBF
	dd 0xFFEFF7EF, 0xBFEFE7F5, 0xBFBFE7E5, 0xFFAFB7E7
	dd 0xBFFFAFB5, 0xBFAFFFAF, 0xFFAFA7FF, 0xFFEFA7A5