PUBLIC	gcm
; Function compile flags: /Ogtpy
_TEXT	SEGMENT
max$ = 8
n$ = 16
gcm	PROC

; 16   :     U64 c, lcm;
; 17   : 
; 18   :     for( c = 1; ( ~n & 1 ) && ( c < 4096 ); c <<= 1 ) n >>= 1;

	movzx	eax, dl
	mov	r8d, 1
	mov	r9, rdx
	not	al
	test	al, r8b
	je	SHORT $LN1@gcm
$LL3@gcm:
	cmp	r8, 4096				; 00001000H
	jae	SHORT $LN1@gcm
	shr	r9, 1
	add	r8, r8
	movzx	eax, r9b
	not	al
	test	al, 1
	jne	SHORT $LL3@gcm
$LN1@gcm:

; 19   :     lcm = n * 4096;

	shl	r9, 12

; 20   :     return ( max / lcm ) * lcm;

	xor	edx, edx
	mov	rax, rcx
	div	r9
	imul	rax, r9

; 21   : }

	ret	0
gcm	ENDP