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mg_notes:general:mem_map [2017/10/12 14:13]
M.G. created
mg_notes:general:mem_map [2017/10/12 14:21] (current)
M.G. [Main RAM / IIgs Bank 0]
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 ===== Main RAM / IIgs Bank 0 ===== ===== Main RAM / IIgs Bank 0 =====
  
-The IIgs supports shadowing of the Bank 0 screen buffers to bank $E0 Mega II "Slow RAM".+The IIgs screen buffers listed are not where the hardware actually draws them from.  The real screen buffers are in Mega II "Slow RAM" bank $E0 and $E1.  The IIgs hardware ​supports shadowing of the Bank 0 screen buffers to bank $E0.
  
 ^ Address(es) ^ Use ^ ^ Address(es) ^ Use ^
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 | 0800--09FF | Boot firmware loads block 0 here | | 0800--09FF | Boot firmware loads block 0 here |
 | 0800--0CFF | Text screen 2 | | 0800--0CFF | Text screen 2 |
-| 1000--.... | ProDOS 8 loads ATINIT here |+| 1000--.... | ProDOS 8 loads ATINIT here (ATINIT size must not stomp on the ProDOS init code) |
 | 1000--12FF | ProDOS 8 copies QUIT code here and jumps to it | | 1000--12FF | ProDOS 8 copies QUIT code here and jumps to it |
-| 2000--.... | ProDOS 8 system programs load here |+| 2000--BEFF | ProDOS 8 system programs load here |
 | 2000--4000 | HGR page 1 | | 2000--4000 | HGR page 1 |
 | 4000--6000 | HGR page 2 | | 4000--6000 | HGR page 2 |
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 | BE00--BEFF | BASIC.SYSTEM global page | | BE00--BEFF | BASIC.SYSTEM global page |
 | BF00--BFFF | ProDOS 8 global page | | BF00--BFFF | ProDOS 8 global page |
 +| C000--CFFF | I/O space \\ On IIgs this is mapped to Mega II |
 | C000--C0FF | [[mg_notes:​general:​io_page|I/​O Page]] | | C000--C0FF | [[mg_notes:​general:​io_page|I/​O Page]] |
 | C080--C0FF | Slots (or ports) 0--7 Device Select $C080+$n0--$C08F+$n0 (usually H/W) | | C080--C0FF | Slots (or ports) 0--7 Device Select $C080+$n0--$C08F+$n0 (usually H/W) |
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 ===== Aux RAM / IIgs Bank 1 ===== ===== Aux RAM / IIgs Bank 1 =====
  
-The IIgs supports shadowing of the Bank 1 screen buffers to bank $E1 Mega II "Slow RAM".+The IIgs screen buffers listed are not where the hardware actually draws them from.  The real screen buffers are in Mega II "Slow RAM" bank $E0 and $E1.  The IIgs hardware ​supports shadowing of the Bank 1 screen buffers to bank $E1.
  
 | 0000--00FF | Aux Zero Page | | 0000--00FF | Aux Zero Page |