home *** CD-ROM | disk | FTP | other *** search
/ Apple II Magazines (PO) / Nibble Volume 10, No. 10 (1989-10)(MindCraft Publishing)(Side A).zip / Nibble Volume 10, No. 10 (1989-10)(MindCraft Publishing)(Side A).po / HR.INVERTER.S < prev    next >
Text File  |  1996-12-24  |  652b  |  25 lines
  1. **********************************
  2. * HR.INVERTER SOURCE CODE        *
  3. * BY ERNIE ALEXANDER             *
  4. * COPYRIGHT(C) 1989              *
  5. * MINDCRAFT PUBL. CORP.          *
  6. * CONCORD, MA. 01742             *
  7. **********************************
  8. * EDITOR ASSEMBLER
  9.           ORG $300 STARTING ADDRESS
  10. SCREEN    EQU $00 zero page usage (2 bytes)
  11.           LDA #$20 Page # ($20 or $40)
  12.           STA SCREEN+1
  13.           LDY #$00
  14.           STY SCREEN
  15.           LDX #$20
  16. INVERT    LDA (SCREEN),Y
  17.           EOR #$FF   *or #$7F
  18.           STA (SCREEN),Y
  19.           INY
  20.           BNE INVERT
  21.           INC SCREEN+1
  22.           DEX
  23.           BNE INVERT
  24.           RTS
  25.