Something

o600 sub (horizontal pass)
G0 Z[#<z_safe>] 		
X[#<x_min>+#<dia_offset>+#<edge_finish>] Y[#<y_now>]
Z[#<z_now>+#<z_pass>+#<z_vertrapid>]
G1 F[#<feed_plunge>] Z[#<z_now>]	
F[#<feed_linear>] X[#<x_max>-#<dia_offset>-#<edge_finish>]	
G0 Z[#<z_safe>]
o600 endsub

o600 call [#<x_min>] [#<x_max>] [#<y_now>] [#<dia_offset>] [#<edge_finish>] [#<feed_linear>] [#<feed_plunge>] [#<z_now>] [#<z_pass>] [#<z_vertrapid>] [#<z_safe>]