multiboot.cpp


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#include "textoutput.hpp"

#include <cstdint>

extern TextOutput& term;

std::uint32_t multiboot_magic;
std::uint32_t *multiboot_ptr;

std::uint32_t lowerMem = 0;
std::uint32_t upperMem = 0;

bool multiboot_initialize()
{
    if (multiboot_magic != 0x36d76289) {
        term.write("Not multiboot!");
        return false;
    }

    term.write("Found multiboot headers: ");

    auto ptr = multiboot_ptr + 2;
    while (ptr[0] != 0 && ptr[1] != 8) {
        term.write(ptr[0]);
        term.write(", ");

        if (ptr[0] == 4) {
            lowerMem = ptr[2] * 1024;
            upperMem = ptr[3] * 1024;
        }
    
        auto next = reinterpret_cast<std::uintptr_t>(ptr);
        next += ptr[1];
        next = (next + 7) & ~7;
        ptr = reinterpret_cast<std::uint32_t *>(next);
    }

    term.write('\n');
    return true;
}