kernel.cpp

#include "gdt.h"
#include "interrupts.h"
#include "types.h"

typedef void (*constructor)();
extern "C" constructor start_ctors;
extern "C" constructor end_ctors;
extern "C" void callConstructors()
{
    for(constructor* i = &start_ctors; i != &end_ctors; i++)
        (*i)();
}

void printf(char* str)
{
    static uint16_t* VideoMemory = (uint16_t*) 0xb8000;
    static uint8_t x = 0, y = 0;

    for (int32_t i = 0; str[i] != '\0'; ++i)
    {
        switch (str[i])
        {
        case '\n':
            x = 0;
            y++;
            break;

        default:
            VideoMemory[80*y+x] = (VideoMemory[80*y+x] & 0xFF00) | str[i];
            x++;
            break;
        }

        if (x >= 80)
        {
            x = 0;
            y++;
        }

        if (y >= 25)
        {
            for (y = 0; y < 25; y++)
                for (x = 0; x < 80; x++)
                    VideoMemory[80*y+x] = (VideoMemory[80*y+x] & 0xFF00) | ' ';
            
            x = 0;
            y = 0;
        }
    }
}

extern "C" void kernelMain(void* multiboot_structure, uint32_t /*multiboot_magic*/)
{
    printf("Hello world!\n--8/11/2019\n");

    printf("Activating interrupts...\n");
    GlobalDescriptorTable gdt;
    InterruptManager interrupts(0x20, &gdt);
    interrupts.Activate();

    printf("Interrupts activated.\n");

    while(1)
    {
        // printf("while(1);\n");
    };
}