XLIB	Compare

; ******************************************************************************
;
;	Compare two signed 8bit integers in A and B.
;
;	Design & programming by Gunther Strube,	Copyright	(C) InterLogic	1995
;
;	Result return as:
;		Fz =	1:	A >=	B
;		Fz =	0:	A < B
;
;	Register affected on return:
;		A.BCDEHL/IXIY
;		.F....../....
;
.Compare			PUSH	BC
				LD	C,A					; preserve original	value of A
				CP	B					; execute	real	comparison
				LD	A,0
				LD	B,A					; now use	registers	as logical flags
				CALL	PE,Set_Overflow		; set overflow	flag
				CALL	M,Set_Minus			; set minus flag
				XOR	B					; perform	P/V XOR S
				LD	A,C					; restore	A
				POP	BC					; restore	BC
				RET						; if	(P/V	XOR S) = 0, then A >= B
.Set_overflow		CPL						; A logical true
				RET
.Set_minus		LD	B,$FF				; B logical true
				RET