549
edits
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Line 494:
Line 494: − + − + − + − +
This stuff isn't limited to IO, but is also e.g. used to map VRAM
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|-
| <code>0b11111111100x</code>
| <code>0b11111111100x</code>
| Map IO address range
| Map address range
| Bits 0-19: index of the first IO page to map; Bit 20: Map read-only (otherwise read-write). Another 0b11111111100x must follow this one to denote the (exclusive) end of the IO range to map.
| Describes a memory mapping like the 0b111111111110 descriptor, but an entire range rather than a single page is mapped. Another 0b11111111100x descriptor must follow this one to denote the (exclusive) end of the address range to map.
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|-
| <code>0b111111111110</code>
| <code>0b111111111110</code>
| Map single IO page
| Map memory page
| Bits 0-19: IO page index to map; Bit 20: Map read-only (otherwise read-write)
| Bits 0-19: page index to map (virtual address >> 12; the physical address is determined by subtracting 0x0EB00000); Bit 20: Map read-only (otherwise read-write)
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