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base:memory_management [2018-05-29 02:38]
white_flame
base:memory_management [2018-05-29 08:18] (current)
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 ^Name ^Bit ^Region ^0 ^1 ^Notes^ ^Name ^Bit ^Region ^0 ^1 ^Notes^
-|LORAM|0|$A000-BFFF|RAM|BASIC|If KERNAL isn't mapped in, then BASIC won't map in either and this area stays as RAM.|+|LORAM|0|$A000-BFFF|RAM|BASIC|If KERNAL isn't mapped in, then BASIC won't map in either and this region ​stays mapped to RAM.|
 |HIRAM|1|$E000-FFFF|RAM|KERNAL| | |HIRAM|1|$E000-FFFF|RAM|KERNAL| |
-|CHAREN|2|$D000-DFFF|CHARROM|I/​O|If HIRAM and LORAM are both set to 0, then this bit is ignored and the area maps to RAM. This allows for 3 mappings of this area: RAM, CHARROM, or I/O.|+|CHAREN|2|$D000-DFFF|CHARROM|I/​O|If HIRAM and LORAM are both set to 0, then this bit is ignored and the area also maps to RAM. This allows for 3 mappings of this region: RAM, CHARROM, or I/O.|
  
   * All other memory locations ($0000-9FFF,​ $C000-CFFF) always map to RAM.   * All other memory locations ($0000-9FFF,​ $C000-CFFF) always map to RAM.
-  * Writes to a ROM-mapped ​area affect ​the underlying RAM at the same address. +  * Writes to a ROM-mapped ​region are applied to the underlying RAM at the same address
-  * The VIC-II ​sees always the CHARROM at $1000-1FFF and $9000-9FFF, and RAM everywhere else, regardless of these bits.+  * I/O includes the registers for the VIC-II, SID, and CIA chips; color RAM; and two external I/O pages that reach out the expansion port
 +  * The VIC-II always ​sees the CHARROM at $1000-1FFF and $9000-9FFF, and RAM everywhere else, regardless of these bits.
  
 The mappings from combining these 3 bits are listed below. ​ Higher bits of location $01 are used for other purposes and default to %00110xxx. The mappings from combining these 3 bits are listed below. ​ Higher bits of location $01 are used for other purposes and default to %00110xxx.
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 |$37 +55 %111 |BASIC |I/O |KERNAL|Default| |$37 +55 %111 |BASIC |I/O |KERNAL|Default|
  
-The cartridge port also has the GAME and EXROM pins, which meddle with the memory map even further. ​ See the Programmer'​s Reference Guide information ​for that.+The cartridge port also has the GAME and EXROM pins, which meddle with the memory map even further. ​ See the Programmer'​s Reference Guide for that.
  
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base/memory_management.1527554329.txt.gz · Last modified: 2018-05-29 02:38 by white_flame