// mm.c
// 09/01/03 Josh Holtrop

// 0x368000 is first available byte (this is right after the kernel @ 1mb and the initrd @ 2mb, 1440kb.


pageblock *first_pageblock = (pageblock *) 0;
dword	mm_totalmem = 0x100000;				//assume 1mb

void	mm_init()
{
	dword	*memmap_entries = (dword *) 0x9040A;
	memmap_entry	*maps = (memmap_entry *) 0x92000;
	dword a;
	for (a=0;a<(*memmap_entries);a++)
	{
		if (maps[a].attributes == 1)		// (1) mem free to OS
		{
			mm_totalmem += maps[a].limit.lowdword;
			if  ((maps[a].base.lowdword + maps[a].limit.lowdword) > (FREERAM_START+8192))	//goes past where we start freeram
			{
				if (maps[a].base.lowdword < FREERAM_START)
				{
					maps[a].limit.lowdword = maps[a].limit.lowdword - (FREERAM_START - maps[a].base.lowdword);
					maps[a].base.lowdword = FREERAM_START;	//block at least 4kb, starts >= FREERAM_START
				}
				if (first_pageblock == 0)	//no pageblock page set up yet, so set it up here
				{
					first_pageblock = (pageblock *) maps[a].base.lowdword;
					maps[a].base.lowdword += 4096;
					maps[a].limit.lowdword -= 4096;
					mm_init_pageblockpage(first_pageblock);
					first_pageblock->base = maps[a].base.lowdword;
					first_pageblock->length = maps[a].limit.lowdword / 4096;
					first_pageblock->flags = MM_PB_AVAIL;
				}
				else				//first_pageblock already set up, add on segment
				{
					pageblock *pb = first_pageblock;
					for (;;)
					{
						if (pb->flags == MM_PB_NP)
							break;
						else
							pb++;
					}
					pb->base = maps[a].base.lowdword;
					pb->length = maps[a].limit.lowdword / 4096;
					pb->flags = MM_PB_AVAIL;
				}
			}
		}
	}
	if (first_pageblock == 0)
	{
		printf("ERROR! NO INITIAL PAGE BLOCK COULD BE CREATED.");
		asm("cli");
		asm("hlt");
	}
}




void	mm_init_pageblockpage(pageblock *pbp)
{
	pageblock *pb = pbp;
	int a;
	for (a=0; a<512; a++)
	{
		pb->base = 0;
		pb->length = 0;
		pb->flags = MM_PB_NP;
		if (a<511)
			pb->link = (dword)++pb + sizeof(pageblock);
		else
			pb->link = 0;
	}
}


void   *mm_palloc(dword numpages)
{


}


int	mm_pfree(void *ptr)
{



}