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Text File  |  2023-02-26  |  2KB  |  102 lines
  1. ..
  2.  
  3.  
  4. Commodore VIC-20
  5. Memory Blocks Illustrated
  6. Leif Bloomquist, 
  7. leif@schemafactor.com
  8.  
  9. Table 1
  10. +-----+----+---------+-------+
  11. : Dec : Hex:Block#   : Usage :
  12. +-----+----+---------+-------+
  13. :57344:E000:Block7 ! :KERNAL!:
  14. ------+----+---------+-------+
  15. :49152:C000:Block6 ! :BASIC !:
  16. +-----+----+---------+-------+
  17. :40960:A000:Block5 " :(1)(2)":
  18. +-----+----+---------+-------+
  19. :32768:8000:Block4   :        ->Table2
  20. +-----+----+---------+-------+
  21. :24576:6000:Block3 " :      ":
  22. +-----+----+---------+-------+
  23. :16384:4000:Block2 " :      ":
  24. +-----+----+---------+-------+
  25. :8192 :2000:Block1 " :      ":
  26. +-----+----+---------+-------+
  27. :0    :0000:Block0   :        ->Table3
  28. +-----+----+---------+-------+
  29.  
  30. ->TABLE 2
  31. +-----+----+--------+--------+------+
  32. :Dec  :Hex :Unexpand:3KExpans:8K+Exn:
  33. +-----+----+--------+--------+------+
  34. :38912:9800:  I/O $ :  I/O  $: I/O $:
  35. +-----+----+--------+--------+------+
  36. :38400:9600:Col Memc:Col Memc:   - !:
  37. +-----+----+--------+--------+------+
  38. :37888:9400:   -   !:  -    !:SColMc:
  39. +-----+----+--------+--------+------+
  40. :36864:9000:VICVIA $:VICVIA $:VICVI$:
  41. +-----+----+--------+--------+------+
  42. :32768:8000:CharROM!:CharROM!:CharRO:
  43. +-----+----+--------+--------+------+
  44.  
  45.  
  46. ->TABLE 3
  47. +----+----+--------+--------+-------+
  48. :7680:1E00:ScreMem%:ScreMem%:UsrBasi:
  49. +----+----+--------+--------:       :
  50. :4608:1200:UsrBasic:        :AREA(3):
  51. +----+----:        :        :-------+
  52. :4096:1000:   AREA :        :ScrMem :
  53. +----+----+--------+--------+-------+
  54. :1024:0400:3kAvail":       ":3KAvai":
  55. +----+----+--------+--------+-------+
  56. :   0:0000:BASWMem$:BASWMem$:BASWMe$:
  57. +----+----+--------+--------+-------+
  58.  
  59. BASIC starts at 4097
  60. BASIC starts at 1025
  61. BASIC starts at 4609
  62.  
  63. Legend:
  64. ! =  ROM
  65. * =  RAM Built-in RAM
  66. " =  EXP Avail for external expansion
  67. $ =  I/O Used by Kernal, BASIC, or IO
  68. % =  SCRN RAM Used for screen display
  69. BASWMem = Basic Working Memory
  70.  
  71.  
  72. Notes:
  73. (1) 8K Cartridges normally here
  74. (Autostart).
  75.  
  76. (2) SYS64802 performs a soft-reset
  77. which usually starts Autostart
  78. cartridge mages.
  79.  
  80. (3) User BASIC Area continues beyond
  81. $2000 with 8K+ Expansion.
  82.  
  83. Tips:
  84. - To find where BASIC Area starts
  85. : PEEK(43) + 256*PEEK(44)
  86.  
  87. - To find where BASIC Area ends
  88. : PEEK(55) + 256*PEEK(56) (These can
  89. also be changed to protect memory
  90. from BASIC)
  91.  
  92. - To find which "page" screen memory
  93. starts: PEEK(648)
  94.  
  95. 30 = $1E, meaning $1E00 (Unexpanded
  96. or 3K expanded VIC)
  97.  
  98. 16 = $10, meaning $1000 (8K or more
  99. expansion)
  100.  
  101. ..END..
  102.