sd:appendix_3_memory_map
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| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| sd:appendix_3_memory_map [2026/02/25 02:50] – appledog | sd:appendix_3_memory_map [2026/02/27 01:41] (current) – appledog | ||
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| == Memory Map | == Memory Map | ||
| - | === BANK 0 - User RAM & System Variables ($00, | + | === BANK 0 – User RAM & System Variables ($00, |
| ^ Address Range ^ Size ^ Name / Area ^ Description / Notes ^ | ^ Address Range ^ Size ^ Name / Area ^ Description / Notes ^ | ||
| Line 12: | Line 12: | ||
| **Total free in Bank 0:** ≈65,280 bytes | **Total free in Bank 0:** ≈65,280 bytes | ||
| - | === BANK 1 - KERNAL ROM & HARDWARE ($010000–$01FFFF) | + | === BANK 1 – KERNAL ROM & HARDWARE ($010000–$01FFFF) |
| ^ Address Range ^ Size ^ Name / Symbol ^ Description / Notes ^ | ^ Address Range ^ Size ^ Name / Symbol ^ Description / Notes ^ | ||
| - | | $010000–$0100FF | 256 bytes | Kernal | + | | $010000–$0100FF | 256 bytes | Kernal |
| | $010100–$013FFF | ~16 KB | Kernal Code | Main KERNAL routines + limited expansion space | | | $010100–$013FFF | ~16 KB | Kernal Code | Main KERNAL routines + limited expansion space | | ||
| | $014000–$01DBFF | 40,960 bytes | RESERVED | Reserved for future KERNAL expansion | | | $014000–$01DBFF | 40,960 bytes | RESERVED | Reserved for future KERNAL expansion | | ||
| Line 25: | Line 25: | ||
| | $01EC00–$01ECFF | 256 bytes | SCRATCH_BUFFER | General-purpose scratch space (used by INPUT, expression eval, parsing, etc.) | | | $01EC00–$01ECFF | 256 bytes | SCRATCH_BUFFER | General-purpose scratch space (used by INPUT, expression eval, parsing, etc.) | | ||
| | $01ED00–$01EDFF | 256 bytes | INPUT_BUFFER | Input line buffer (also used as part of PATB system variables) | | | $01ED00–$01EDFF | 256 bytes | INPUT_BUFFER | Input line buffer (also used as part of PATB system variables) | | ||
| - | | $01EE00–$01EEFF | 256 bytes | PATB_VARIABLES + stacks etc. | PATB_BASIC variables, expression stack, GOSUB/FOR stacks, program pointers… | | + | | $01EE00–$01EEFF | 256 bytes | PATB_VARIABLES + stacks etc. | PATB_BASIC variables, expression stack, GOSUB/FOR stacks, program pointers | |
| - | | $01EF00–$01EF0B | 12 bytes | Video System Registers | VIDEO_MODE, VIDEO_COLUMNS, | + | | $01EF00–$01EF0B | 12 bytes | Video System Registers | VIDEO_MODE, VIDEO_COLUMNS, |
| | $01EF0C–$01EF0F | 4 bytes | Cursor System | CURSOR_BLINK, | | $01EF0C–$01EF0F | 4 bytes | Cursor System | CURSOR_BLINK, | ||
| | $01EF10–$01EF31 | 34 bytes | Keyboard System | KBD_STATUS_FLAGS, | | $01EF10–$01EF31 | 34 bytes | Keyboard System | KBD_STATUS_FLAGS, | ||
| Line 33: | Line 33: | ||
| | $01EF43–$01EF49 | 7 bytes | Extended Video System | VIDEO_COLOR_MODE, | | $01EF43–$01EF49 | 7 bytes | Extended Video System | VIDEO_COLOR_MODE, | ||
| | $01EF4A–$01EF7F | 54 bytes | FREE | Reserved for hardware expansion | | | $01EF4A–$01EF7F | 54 bytes | FREE | Reserved for hardware expansion | | ||
| - | | $01EF80–$01EFBF | 64 bytes | Sound System (4 voices) | 4 × SID-like voices (frequency, gate, ADSR, volume, etc.) | | + | | $01EF80–$01EFBF | 64 bytes | Sound System (4 voices) | see: [[Appendix 5 Sound System|SD-450 Sound System]] |
| | $01EFC0–$01EFFF | 64 bytes | FREE | Reserved for sound system expansion | | | $01EFC0–$01EFFF | 64 bytes | FREE | Reserved for sound system expansion | | ||
| - | | $01F000–$01F3E7 | 1,000 bytes | VM1_TEXT_BASE | Video Mode 1 – 40×25 text character map | | + | | $01F000–$01F3E7 | 1,000 bytes | VM1_TEXT_BASE | Video Mode 1 -- 40×25 text character map | |
| - | | $01F3E8–$01F7FF | 1,048 bytes | FREE (text area) | — | | + | | $01F3E8–$01F7FF | 1,048 bytes | FREE (text area) | | |
| - | | $01F800–$01FBE7 | 1,000 bytes | VM1_COLOR_BASE | Video Mode 1 – 40×25 color attribute map | | + | | $01F800–$01FBE7 | 1,000 bytes | VM1_COLOR_BASE | Video Mode 1 -- 40×25 color attribute map | |
| - | | $01FBE8–$01FFFF | 1,048 bytes | FREE (color area) | — | | + | | $01FBE8–$01FFFF | 1,048 bytes | FREE (color area) | | |
| - | === BANK 2 – USER RAM ($020000–$02FFFF) | + | === BANK 2 -- USER/ |
| ^ Address Range ^ Size ^ Name / Area ^ Description ^ | ^ Address Range ^ Size ^ Name / Area ^ Description ^ | ||
| - | | $020000–$02FFFF | 65,536 B | User RAM | Completely free | | + | | $020000–$02FFFF | 65,536 B | User RAM | Mode 1: Free | |
| + | | $020000–$02FFFF | 65,536 B | User RAM | Mode 2: Free | | ||
| + | | $020000–$02FFFF | 65,536 B | User RAM | Mode 3+: Reserved | ||
| - | === BANK 3 – USER RAM ($030000–$03FFFF) | + | === BANK 3 -- USER RAM ($030000-$03FFFF) |
| ^ Address Range ^ Size ^ Name / Area ^ Description ^ | ^ Address Range ^ Size ^ Name / Area ^ Description ^ | ||
| - | | $030000–$03FFFF ^ 65,536 B | User RAM | Completely | + | | $030000–$03FFFF ^ 65,536 B | User RAM | free | |
| === Quick Free Space Summary | === Quick Free Space Summary | ||
| Line 55: | Line 57: | ||
| | 0 | 65,280 | Mostly user RAM + small BASIC area | | | 0 | 65,280 | Mostly user RAM + small BASIC area | | ||
| | 1 | ~40,960 | Reserved for future KERNAL expansion | | | 1 | ~40,960 | Reserved for future KERNAL expansion | | ||
| - | | 2 | 65,536 | Completely free | | + | | 2 | 65,536 | Mode 1 and 2: Free / Graphics Mode 3 and up: Reserved |
| | 3 | 65,536 | Completely free | | | 3 | 65,536 | Completely free | | ||
| | **Total** | **237,312** | Available for user programs & data | | | **Total** | **237,312** | Available for user programs & data | | ||
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