page.c

//
// Created by reindeer002-laptop on 3/17/26.
//

#include "page.h"

void kInitializePageTables() {
    PML4TENTRY* pstPML4TEntry;
    PDPTENTRY* pstPDPTEntry;
    PDENTRY* pstPDEntry;
    DWORD dwMappingAddress;

    pstPML4TEntry = ( PML4TENTRY* ) 0x100000;
    kSetPageEntryData(&(pstPML4TEntry[0]), 0, 0x101000, PAGE_FLAGS_DEFAULT, 0);
    for(int i = 1; i < PAGE_MAXENTRYCOUNT; i++) {
        kSetPageEntryData(&(pstPML4TEntry[i]), 0, 0, 0, 0);
    }

    pstPDPTEntry = ( PDPTENTRY* ) 0x101000;
    for(int i = 0; i < PAGE_MAXENTRYCOUNT; i++) {
        if (i < 64) {
            kSetPageEntryData(&(pstPDPTEntry[i]), 0, 0x102000 + (i * PAGE_TABLESIZE), PAGE_FLAGS_DEFAULT, 0);
        } else {
            kSetPageEntryData(&(pstPDPTEntry[i]), 0, 0, 0, 0);
        }
    }

    pstPDEntry = ( PDENTRY* ) 0x102000;
    dwMappingAddress = 0;
    for(int i = 0; i < PAGE_MAXENTRYCOUNT * 64; i++) {
        kSetPageEntryData(&(pstPDEntry[i]), (i * (PAGE_DEFAULTSIZE >> 20)) >> 12, dwMappingAddress, PAGE_FLAGS_DEFAULT | PAGE_FLAGS_PS, 0);
        dwMappingAddress += PAGE_DEFAULTSIZE;
    }
}

void kSetPageEntryData(PTENTRY* pstEntry, DWORD dwUpperBaseAddress, DWORD dwLowerBaseAddress, DWORD dwLowerFlags, DWORD dwUpperFlags) {
    pstEntry->dwAttributeAndLowerBaseAddress = dwLowerBaseAddress | dwLowerFlags;
    pstEntry->dwUpperBaseAddressAndEXB = (dwUpperBaseAddress & 0xFF) | dwUpperFlags;
}