10 ;  ÍÆÉÌÌ   öåò® ±›20 ;›30 ; COPYRIGHT (C) 1982 BY DAVID FOX AND MITCHELL WAITE›40 ;›0100  .TITLE "CLK-MFILL1.ASM;v01.00,810907-820407"›0110  .PAGE "Memory Fill Routine"›0120 ;›0130 ; BY COREY L. KOSAK›0140 ;›0150 ; Called from BASIC with TEMP=USR(MFILL,START,LEN,BYTE)›0160 ;›0170 ; THIS IS THE ATARI BASIC VERSION (USE ver.2 WITH MBASIC)›0180  *=$600›0190 LO=$CB ;POINTER TO DATA›0200 HI=$CC›0210 LENLO=$CD ;LENGTH IN BYTES›0220 LENHI=$CE›0230 MFILL PLA ;REMOVE STACK BIAS›0240  PLA ;ADDRESS...›0250  STA HI ;HI›0260  PLA›0270  STA LO ;LO›0280  PLA ;LENGTH...›0290  STA LENHI ;HI›0300  PLA›0310  STA LENLO ;LO›0320  PLA ;BYTE TO FILL HI (SHOULD BE ZERO - SO IGNORE IT)›0330  PLA ;DATA›0340  LDY #$00›0350  TAX ;SAVE FILL BYTE IN X-REG›0360 LOOP TXA ;AND TRANSFER IT BACK›0370  STA (LO),Y ;STORE BYTE›0380  INY ;BUMP POINTER›0390  BNE OK ;DID IT ROLL OVER?›0400  INC HI ;YES, INC HI BYTE›0410 OK LDA LENLO ;DECREMENT LENGTH BYTES›0420  BNE OK2›0430  DEC LENHI›0440 OK2 DEC LENLO›0450  LDA LENLO ;DOES LENGTH=0?›0460  ORA LENHI ;......?›0470  BNE LOOP ;NO, GO BACK FOR MORE›0480 DONE RTS ;LEAVE.›