/*
 * mem-phys.c
 *
 *  Created on: Aug 27, 2011
 *      Author: Tiberiu
 */

#include <stdlib.h>
#include "mem.h"

uint32* FrameMap;
uint32 TotalFrames;
uint32 TotalMemory;

void ConvertIndexToFrame (uint32 index, uint32* address, uint32* offset)
{
	*address = (index >> 5);
	*offset = index & 0x1f;
}

uint32 ConvertFrameToIndex (uint32 address, uint32 offset)
{
	return (address<<5) | offset;
}

void MemPhSetFrame (uint32 frame, uint8 value)
{
	uint32 addr, off;
	ConvertIndexToFrame(frame, &addr, &off);

	if (value) FrameMap[addr] |= 1<<off;
	else FrameMap[addr] &= ~(1<<off);
}

uint32 MemPhGetFrame (uint32 frame)
{
	uint32 addr, off;
	ConvertIndexToFrame(frame, &addr, &off);

	return FrameMap[addr] & (1<<off);
}

uint32 MemPhFindFreeFrame()
{
	uint32 addr, pos;

	for (addr = 0; addr < TotalFrames >> 5; addr++)
		if (FrameMap[addr] != 0xffffffff)
		{
			for (pos = 0; (FrameMap[addr] & (1<<pos)) != 0; pos++) ;

			return ConvertFrameToIndex(addr, pos);
		}

	return 0;
}

void MemPhAllocFrame(uint8 isKernel, uint8 isWriteable)
{
	//if (page->Frame != 0) return;

	uint32 free = MemPhFindFreeFrame();
	if (!free) return;

	LogMem("Physical: allocated frame %u.\n", free);

	MemPhSetFrame(free, 1);
	/*page->Present = 1;
	page->User = (isKernel) ? 0 : 1;
	page->Writeable = (isWriteable) ? 1 : 0;
	page->Frame = free;*/
}

/*void MemPhFreeFrame()//Page* page)
{
	uint32 frame = page->Frame;
	if (!frame) return;

	MemPhSetFrame(frame, 0);
	page->Frame = 0;
}*/

void MemPhInitialize(uint32 SystemMemoryKb)
{
	LogMem("Starting physical memory manager...\n");
	TotalFrames = SystemMemoryKb >> 2;
	TotalMemory = SystemMemoryKb;

	FrameMap = (uint32*) malloc(sizeof(uint32) * (1 + (TotalFrames>>5)));
	memset(FrameMap, 0, sizeof(uint32) * (1 + (TotalFrames>>5)));
	LogMem("Started ok!, found %ukb total_frames=%u\n", SystemMemoryKb, TotalFrames);
}

void MemPhReserveFrames (uint32 address, uint32 length)
{
	address >>= 12;
	length = (length>>12) + ((length & 0xfff) > 0);
	uint32 end = address + length;

	for (; address < end && address < TotalFrames ; address++)
		MemPhSetFrame(address, 1);
}