Lost all oil pressure no oil getting to top of engine

mileage?..over heated? oil to top is function of oil pump and oil passageways ..bad worn lower engine (crankshaft/bearings)......oil pump push rod..under distributor driven gear down into block to oil pump in oil pan..clogged passages/oil filter/oil filter bypass...... do a oil pressure test while cranking from port on side of block low and determine if bottom end has the pressure first