src/boot/multiboot2.cc


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#include "multiboot2.hpp"
#include "libs/string.hpp"
#include "libs/stdio.hpp"

u32* mb2_find_tag(u32 *mb2_info_addr, char type){
    u32 size=(u32)mb2_info_addr[0];

    char *location=((char*)mb2_info_addr)+8; // Goto first tag
    char *start=(char*)mb2_info_addr;

    while((location-start) < size){
        // Goto next 64bit align address
        while(((u64)location&0x7) != 0)
            location++;
        // Parse type
        u32 cur_type=((u32*)location)[0];
        u32 cur_size=((u32*)location)[1];

        if(cur_type==type){
            return (u32*)location;
        }
        location+=cur_size;
    }

    return 0;
}

char mb2_find_bootloader_name(u32* mb2_info_addr, char *return_name){
    u32* addr=mb2_find_tag(mb2_info_addr,2);
    if(addr){
        u32 size=addr[1];
        memcpy(addr+2, return_name, size);
        return 1;
    }
    return 0;
}
char mb2_find_new_rsdp(u32* mb2_info_addr, u64 *return_addr, u32 *return_size){
    u32* addr=mb2_find_tag(mb2_info_addr,15);
    if(addr){
        *return_size=addr[1];
        *return_addr=(u64)(addr+2);
        return 1;
    }
    return 0;   
}

char mb2_find_old_rsdp(u32* mb2_info_addr, u64 *return_addr, u32 *return_size){
    u32* addr=mb2_find_tag(mb2_info_addr,14);
    if(addr){
        *return_size=addr[1];
        *return_addr=(u64)(addr+2);
        return 1;
    }
    return 0;   
}