G-code format

how do i set g28.1 to use g28

i got this g28.1 (x-2 y2 z.2)
<<<<<codes>>>>>>>>>
g28
but g28 go to xyz zeros

i tried g28.1 =
but it no like the =
thanks

i think i see.

g0 x1 y1 z1
g28.1
<<<<codes>>>

g28

will bring it back to x1 y1 z1 when it hit g28
but it has to go to that point FIRST to be recorded.
i don't see the point, why not just put g0 x1 y1 z1 at the end of the file?
why make the move to start with?

and can someone explain how to use global in subroutine?

i have;

%
g17 g20 g40 g49 g54 g80 g90 g94
(Mill Four Ports)
#<feed> = 4
o100 sub
f#<1>
x.04 y.04
y2.27
x1.21
y.04
x.04

x.02 y.02
y2.29
x1.23
y.02
x.02
x.04 y.04
o100 endsub

g64 p.005 q.005
g0 x.05 y.05
m6 t5
z.1
o100 call [1]

where does the [1] get its' value? SWPadnos says it nothing to do with "#<feed> = 4" from above,i agree
but no one wants to tell me how to USE <feed> in the sub.i want to be able to change the feed every now a then
and don't want to have to look thru the whole file. i understand a little about functions in c++ and know
i can't use the value of one function in another. but all i need to do put the values outside the function.
is that about the same? THANKS