73 lines
1.8 KiB
PHP
73 lines
1.8 KiB
PHP
;; File: mmu.inc
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;;
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;; About: Address Translation
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;;
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;; Since we don't use segmentation, this is how address translation works
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;; > 31 21 11 0
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;; > +--------+--------+--------+
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;; > | DIR | PAGE | OFFSET |
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;; > +--------+--------+--------+
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;; > |
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;; > v
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;; > Page Translation
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;; > |
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;; > 31 v 0
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;; > +--------------------------+
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;; > | Pyshical address |
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;; > +--------------------------+
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;;
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;; About: Page Translation
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;;
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;; > +--------+--------+--------+ +--------+
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;; > | DIR | PAGE | OFFSET |-----+ | Phys |
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;; > +--------+--------+--------+ +------>| addr |
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;; > | | | |
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;; > | +----+ +--------+
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;; > | Page Dir | +---> Page Frame
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;; > | +---------+ | +--------+ |
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;; > | | | | | | |
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;; > +->| PDE |-+ +->| PTE |-+
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;; > | | | | |
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;; > +---------+ | +--------+
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;; > +----> Page Table
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;; >
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;;
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;; Defines: Page Directory Flags
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;; PDE_P - Present
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;; PDE_W - Writable
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;; PDE_U - User
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;; PDE_PWT - Write-Through
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;; PDE_PS - 4MiB page
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PDE_P = 0x001
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PDE_W = 0x002
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PDE_U = 0x004
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PDE_PWT = 0x008
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PDE_PCD = 0x010
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PDE_A = 0x020
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PDE_D = 0x040
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PDE_PS = 0x080
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PDE_G = 0x100
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;; Defines: Page Table Flags
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;; PTE_P - Present
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;; PTE_W - Writable
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;; PTE_U - User
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;; PTE_PWT - Write-Through
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;; PTE_PCD - Cache Disable
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;; PTE_A - Accessed
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;; PTE_D - Dirty
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;; PTE_PAT - TODO
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;; PTE_G - TODO
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PTE_P = 0x001
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PTE_W = 0x002
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PTE_U = 0x004
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PTE_PWT = 0x008
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PTE_PCD = 0x010
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PTE_A = 0x020
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PTE_D = 0x040
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PTE_PAT = 0x080
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PTE_G = 0x100
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;; PAGE_SIZE: Page size (4Kib)
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PAGE_SIZE = 4096
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