int 0x30 - exit task
int 0x31 - yield to scheduler
int 0x33 - extend data section by eax bytes
           actual amount extended returned in eax

int 0x32 - system call
system call number in eax
args in ebx, ecx, edx, esi, edi
result in eax

 function      | eax | eax out   | ebx           | ecx    | edx    | esi | edi
---------------|-----|-----------|---------------|--------|--------|-----|-----
 vga_blank     | 0x0 |           |               |        |        |     |
 vga_set_color | 0x1 |           | color         |        |        |     |
 vga_printch   | 0x2 |           | char          |        |        |     |
 vga_printsz   | 0x3 |           | sz string     |        |        |     |
 vga_printsn   | 0x4 |           | non-sz string | length |        |     |
               |     |           |               |        |        |     |
 fs_open       | 0x5 | handle    | path          |        |        |     |
 fs_open_root  | 0x6 | handle    |               |        |        |     |
 fs_new        | 0x7 | handle    | path          |        |        |     |
 fs_close      | 0x8 |           | handle        |        |        |     |
 fs_delete     | 0x9 |           | path          |        |        |     |
 fs_exists     | 0xa | does      | path          |        |        |     |
 fs_seek       | 0xb | seeked by | handle        | by     |        |     |
 fs_tell       | 0xc | position  | handle        |        |        |     |
 fs_read       | 0xd | read      | handle        | max    | buffer |     |
 fs_write      | 0xe | written   | handle        | max    | buffer |     |
               |     |           |               |        |        |     |
 plef_run      | 0xf | handle    | image path    |        |        |     |