hi;
you can declare variable this way:

variable_1 equ 030h
this is iram location and you can access it
by all instructions for iram manipulation.
e.g.
mov variable_1,#01h
add a,variable_1
cjne a,variable1,xyz
etc.
if you are using variable in xram declaration shall remain same.only access mechanism shall involve use of dptr and r0/r1
e.g.
variable_2 equ 01000h
mov dptr,#variable_2
movx @dptr,a

one important note.one can make by mistake declare a variable bigger than 0ffh and use it for iram accesses
e.g.
variable_3 equ 02000h
mov a,variable_3
for this assembler shall generate size mismatch error.
enjoy
pranav