35 lines
1.1 KiB
C++
35 lines
1.1 KiB
C++
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#include "MMU.h"
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void MMU::enable(){
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//set each entry to not present
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int i;
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for(i = 0; i < 1024; i++)
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{
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// This sets the following flags to the pages:
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// Supervisor: Only kernel-mode can access them
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// Write Enabled: It can be both read from and written to
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// Not Present: The page table is not present
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this->page_directory[i] = 0x00000002;
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}
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// holds the physical address where we want to start mapping these pages to.
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// in this case, we want to map these pages to the very beginning of memory.
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//we will fill all 1024 entries in the table, mapping 4 megabytes
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for(unsigned int i = 0; i < 1024; i++)
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{
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// As the address is page aligned, it will always leave 12 bits zeroed.
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// Those bits are used by the attributes ;)
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first_page_table[i] = (i * 0x1000) | 3; // attributes: supervisor level, read/write, present.
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}
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// attributes: supervisor level, read/write, present
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this->page_directory[0] = ((unsigned int)first_page_table) | 3;
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loadPageDirectory(this->page_directory);
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enablePaging();
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}
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