; ; ;routine to get the key stroke status for two key roll over check. ;this maintains two active key strokes in the "key1" and "key2" ;variables. key2 is the second key down code. This routine should ;be called periodically (about once each 10-30 milliseconds) ; KEYfetch cjae key1,#KEY_NONE,keyfet_d ;there is no key 1 mov W,key1 call keycheck ;see if key1 still down jc keyfet_a ;key 1 still down ; mov key1,key2 ;key 1 went away to copy 2 to 1 mov key2,#KEY_NONE jmp keyfetch ;retest the new key 1 ; ;processing section when key1 still down keyfet_a cjae key2,#KEY_NONE,keyfet_b ;look for new key2 if none now mov W,key2 call keycheck ;see if key2 still down jc keyfet_x ;exit if key2 still down ; keyfet_b call keycode ;look for a new key2 cjne keycnt,key1,keyfet_c ;skip if this is same as key1 call keynext ;look beyond the key1 bit keyfet_c mov key2,keycnt ;save the "new" key 2 code jmp keyfet_x ; ;processing section when no key so look for new one keyfet_d call keycode mov key1,keycnt ;save the "new" key 1 code ; keyfet_x ret