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Text File  |  1995-03-30  |  2KB  |  76 lines
  1. ORG 53100
  2. ;----------------------------------------------
  3. ;16K VDC RAM - TOOL  BY  KLAUS HEGEMANN 1989
  4. ;----------------------------------------------
  5. :ZERO = 251
  6.  
  7.               JSR $AEFD   ;VDC ANFG.
  8.               JSR $A96B
  9.               LDA $14
  10.               LDX $15
  11.               STA LOW+1
  12.               STX HIGH+1
  13.               JSR ZEROSET
  14.               JSR $AEFD   ;ANFG.
  15.               JSR $A96B
  16.               LDA $14
  17.               LDX $15
  18.               STA ZERO
  19.               STX ZERO+1
  20.               JSR $AEFD   ;ENDE
  21.               JSR $B7EB
  22.               CPX #0
  23.               BNE WRITE
  24.  
  25. :READ         JSR VDCGET
  26.               LDY #0
  27.               STA (ZERO),Y
  28.               JSR ERHOEHERER
  29.               JMP READ
  30.  
  31. :WRITE        LDY #0
  32.               LDA (ZERO),Y
  33.               LDY #31
  34.               JSR VDCPUT
  35.               JSR ERHOEHERER
  36.               JMP WRITE
  37.  
  38. :ERHOEHERER   LDA ZERO
  39.               CLC
  40.               ADC #1
  41.               STA ZERO
  42.               BCC NOPLUS
  43.               INC ZERO+1
  44. :NOPLUS       LDA ZERO
  45.               CMP $14
  46.               BNE LOAD
  47.               LDA ZERO+1
  48.               CMP $15
  49.               BNE LOAD
  50.               PLA
  51.               PLA
  52. :LOAD         RTS
  53.  
  54. :VDCGET       LDY #31
  55.               STY $D600
  56. :GWAIT        BIT $D600
  57.               BPL GWAIT
  58.               LDA $D601
  59.               RTS
  60. :ZEROSET      LDA #80
  61.               LDY #1
  62.               JSR VDCPUT
  63.               LDA #47
  64.               LDY #28
  65.               JSR VDCPUT
  66. :HIGH         LDA #0
  67.               LDY #18
  68.               JSR VDCPUT
  69. :LOW          LDA #0
  70.               INY
  71. :VDCPUT       STY $D600
  72. :PWAIT        BIT $D600
  73.               BPL PWAIT
  74.               STA $D601
  75.               RTS
  76.