Define a bit array table: just values, no storage
FIRSTBIT        EQU     0
SECOND          EQU     3


TWENTIETH       EQU     .20

Define storage for array

BITFLAGS   EQU    START
BITFALGS1 EQU    START+1


Write some macros, such as:

IFBITON         MACRO           A
BMV1            SET             A/8
BMV2            SET             A-(8*BMV1)
                        BTFSC           BITFLAGS+BMV1,BMV2     ; do next if bit
is set
                ENDM

                IFBITON TWENTIETH
will generate a BTFSC   BITFLAGS+2,4

I find this very helpful: I don't have to remember which byte a particular
flag is in, I just need the flag name.