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Code: Select all

    outb(REG_SCREEN_CTRL, 14);
    int offset = inb(REG_SCREEN_DATA) << 8;
    outb(REG_SCREEN_CTRL, 15);
    offset += inb(REG_SCREEN_DATA);
    return offset;

Code: Select all

    *((volatile char *) 0xB80A0) = 'O'; // If the get_cursor_offset() works right, 'H' should cover the 'O'
    *((volatile char *) 0xB80A0 + get_cursor_offset()) = 'H'; 

Code: Select all

ENTRY(_kstart)
OUTPUT_FORMAT("elf64-x86-64")

PHDRS {
    headers PT_PHDR PHDRS;
    text PT_LOAD FILEHDR PHDRS;
    data PT_LOAD;
}

SECTIONS {
    . = 0xffffffff80000000 + SIZEOF_HEADERS;
    .text : {
        *(.text)
        *(.text.*)
    } :text
    .rodata : {
        *(.rodata)
        *(.rodata.*)
    }

    /* Normally, the overlap between text and data section is handled by having
     * two different pages for the last bits of text and the first bits of data.
     * That way, if the last bits of text are overwritten, it won't affect the
     * text that is actually used. Unfortunately, for the kernel this is not
     * possible. The whole file is loaded into memory en bloc, so the same page
     * would be mapped twice. Therefore, a write access to the writable page
     * would end up being visible in the non-writable side of things. Therefore,
     * we must actually page-align here.
     */
    . = ALIGN(2M);
    .data : {
        *(.data)
        *(.data.*)
    } :data
    .bss : {
        *(.bss)
        *(COMMON)
        *(.bss.*)
    }
}