; define bit location and its mask:
#define EXTRA_FLAG_1	0x80,00000001b
#define EXTRA_FLAG_2	0x80,00000010b

; create macros:
; - set bit
SET_BIT		MACRO bit_location, bit_mask
	MOV	R0,#bit_location
	MOV	A,#bit_mask
	ORL	A,@R0
	MOV	@R0,A
		ENDM
; - clear bit
CLR_BIT		MACRO bit_location, bit_mask
	MOV	R0,#bit_location
	MOV	A,#bit_mask
	CPL	A
	ANL	A,@R0
	MOV	@R0,A
		ENDM

; somewhere in a program:
	SET_BIT	EXTRA_FLAG_1
; ...
	CLR_BIT	EXTRA_FLAG_2