Draft for a simple markup format to document / design logic

//////////////////////////////////
// KEY                          //
//////////////////////////////////
// TEXT:  tree label            //
// //     comment               //
// |      branch                //
// +      normal node           //
// *      virtual node          //
// ?      logical node          //
// $      blackbox node         //
// *--|   virtual branch        //
//////////////////////////////////


/////////////////
// fat12 tree  //
/////////////////
partition:
    |
    |--+ BPB
    |  | byte jmp_code[3]
    |  | byte oem[8]
    |  | word bytes_per_sector
    |  | byte sectors per cluster
    |  | word reserved_sectors
    |  | byte number_of_fats
    |  | word directory_entries
    |  | word logical_sectors
    |  | byte media_type
    |  | word sectors_per_fat
    |  | word sectors_per_track
    |  | word heads
    |  | dword hidden_sectors
    |  | dword large_sectors
    |
    |--+ EBR
    |  | byte drive
    |  | byte reserved_flags
    |  | byte signiture
    |  | dword serial
    |  | byte label[11]
    |  | byte identifier[8]
    |  | byte boot_code[448]
    |  | word bootable_partition_sign
    |
    |--? DATA
       |--? FATS
       |  |--+ FAT
       |  |
       |  | FAT_ENTRY
       |  ?
       |
       |
       |--? DIRECTORY
       |  |
       |  |--+ DIRECTORY_ENTRY
       |  |  | byte name[11]
       |  |  | byte attributes
       |  |  | word reserved
       |  |  | word creation_time
       |  |  | word creation_date
       |  |  | word access_date
       |  |  | word write_time
       |  |  | word write_date
       |  |  | word cluster_address_lower
       |  |  | dword size
       |  |
       |  ?
       |
       | FILE_DATA
       |
       ?


////////////////
// Boot tree  //
////////////////

_start(magic, mbi):
    |--$ // set up stack + multiboot stuff
    |
    |--+ __init(magic, mbi)
    |  |
    |  |--$ mem_initialize(magic, mbi)  // setup physical memory management
    |  |
    |  | i = __init_array_end - __init_array_start;
    |  |--? (i--)
    |     |--$ (*__init_array_start[i])(magic, mbi);    // setup pre main() kernel plugins
    |     |
    |     ?
    |
    |--+ main(magic, mbi)
    |  |--$ // verify multiboot structure
    |  |
    |  |--? (i = 0, mod = mbi->mods_addr;i < mbi->mods_count;i++, mod++)
    |     |
    |     |--? (fs_table[i]->is_type(mod->mod_start))
    |     |  |
    |     |  |--$ fs_table[i]->load_module(mod->cmdline, mod->mod_start)  // load ramdisk filesystems loaded as multiboot modules
    |     |
    |     |--? (exec_table[i]->is_type(mod->mod_start))
    |     |  |
    |     |  |--$ exec_table[i]->load_module(mod->cmdline, mod->mod_start)  // load executable multiboot modules
    |     |
    |     ?
    |
    |--+ __fini
    |  |
    |  | i = __fini_array_end - __fini_array_start
    |  |--? (i--)
    |     |--$ (*__fini_array_start[i])(magic, mbi);  // setup post main() kernel plugins
    |     |
    |     ?
    |
    |--+ hang
       |--$ hang()


/////////////////////////
// memory manager map  //
/////////////////////////

mem_initialize(magic, mbi):
    |--? (magic != MULTIBOOT_BOOTLOADER_MAGIC)
    |  |--*
    |
    |--? (CHECK_FLAG (mbi->flags, 6))
    |  |
    |  |--? (mmap = mbi->mmap_addr;mmap < mbi->mmap_addr + mbi->mmap_length;mmap = mmap + mmap->size + sizeof(mmap->size))
    |     |
    |     |--? (mmap->type == MULTIBOOT_MEMORY_AVAILABLE && mmap->addr >= &KERNEL_END)
    |     |  | MEM_POOL_SIZE = mmap->len - (mmap->addr - &KERNEL_END);
    |     |  |
    |     |  |--*
    |     |
    |     ?
    |
    *--|
       |--$ // setup memory map as a doubly linked list


combine_free_blocks:
    |---? (p = MEM_POOL;p->next != MEM_POOL_END;p = p->next)
        |
        |---? (p->free)
        |   |
        |   |---? (c = p;;c = c->next)
        |       |
        |       |---? (! c->free)
        |       |   |
        |       |   |--? (c->prev != p)
        |       |   |  |
        |       |   |  | p->next = c
        |       |   |  | c->prev = p
        |       |   |
        |       |   |--*
        |       |
        |       |--? (c->next == MEM_POOL_END)
        |       |  |
        |       |  |--*
        |       |
        |       ?
        *--|
           ?


mget_free_block(p, size):
    |--$ combine_free_blocks
    |
    |--? (p->ptr != MEM_POOL_END)
    |  |--? (p->free && p->next - p->ptr) >= size)
    |  |  |--*
    |  |
    |  | p = p->next;
    |  |
    |  ?
    |
    *--| p

split_block(selected, size):
    | end_marker = selected->next
    | split->free = true
    | split->prev = selected
    | split->ptr = split + sizeof(mem_entry_t)
    | split->next = end_marker
    | selected->next = split
    | end_marker->prev = split