Elaboration error in vivado at sim_bram_helpers.vhdl

[sasi8985]

ERROR: [VRFC 10-3361] function 'behavioural_initialize' does not always return a value [C:/Users/NALLURI SASI KIRAN/Desktop/microwatt-master/sim_bram_helpers.vhdl:16]
ERROR: [XSIM 43-3321] Static elaboration of top level VHDL design unit core_dram_tb in library work failed.