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struct RSDPDescriptor {
 char Signature[8];
 char Checksum;
 char OEMID[6];
 char Revision;
 unsigned int RsdtAddress;

 unsigned int Length;
 double XsdtAddress;
 char ExtendedChecksum;
 char reserved[3];
};

k_main() // like main in a normal C program
{
	
	int i =0;
        char *address = (char *)0x0000040E;

	struct RSDPDescriptor *rsdp;

	for(i=0;i<1024;i+=16)
	{
		rsdp = (struct RSDPDescriptor *)(address + i);
		if(mystrcmp((*rsdp).Signature,"RSD PTR ") == 0)
		{
			k_printf("Found RSDP1",8);
		}
	}

	char *address2 = (char *)0x0E0000;

	while(address2<=0x0FFFFF)
	{
		rsdp = (struct RSDPDescriptor *)address2;
		if((*rsdp).Signature == "RSD PTR ")
		{
			k_printf("Found RSDP2",9);
		}
		address2 += 16;
	}
	
	k_printf("Not Found",10);
	
}

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#ifndef ACPI_H
#define ACPI_H

#pragma pack(push, 1)

typedef struct _RSDP
{
	char Signature[8];
 	uint8 Checksum;
 	char OemId[6];
 	uint8 Revision;
 	uint32 RsdtAddress;
} RSDP_t;

typedef struct _RSDT
{
	char Signature[4];
	uint32 Length;
	uint8 Revision;
	uint8 Checksum;
	char OemId[6];
	char OemTableId[8];
	uint32 OemRevision;
	char CreatorId[4];
	uint32 CreatorRevision;
} RSDT_t;

typedef struct _MADT
{
	char Signature[4];
	uint32 Length;
	uint8 Revision;
	uint8 Checksum;
	char OemId[6];
	char OemTableId[8];
	uint32 OemRevision;
	char CreatorId[4];
	uint32 CreatorRevision;
	uint32 LapicAddress;
	uint32 Flags;
} MADT_t;

typedef struct _MADTSubtable
{
	uint8 Type;
	uint8 Length;
} MADTSubtable_t;

typedef struct _AcpiLapic
{
	uint8 Type;
	uint8 Length;
	uint8 AcpiId;
	uint8 LapicId;
	uint32 Flags;
} AcpiLapic_t;

typedef struct _AcpiIoApic
{
	uint8 Type;
	uint8 Length;
	uint8 IoApicId;
	uint8 Reserved;
	uint32 Address;
	uint8 IRQBase;
} AcpiIoApic_t;

#pragma pack(pop)

#define MADT_LAPIC 0
#define MADT_IOAPIC 1

bool inline AcpiChecksum(void* ptr, int size)
{
	uint8 accum = 0;
	for(int i = 0; i < size; i++)
	{
		accum += ((uint8*)ptr)[i];
	}
	return (accum == 0);
}

#endif

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#ifndef MP_H
#define MP_H

// Processor Descriptor
typedef struct _Processor
{
	PML4 Pml4; // Processor Specific PML4
	IDT Idt; // Interupt Descriptor Table
	TSS_t* Tss; // System TSS
	virt_addr Stack; // Address of stack for this processor
	CpuFeatures_t Features; // Features retrieved from CPUID
	uint8 LapicId; // Local APIC ID of this processor
	int8 Stage; // Processor Initialization Stage
} Processor_t;

EXTERN Processor_t* MpProcessorTable;
EXTERN uint32 MpProcessorCount;

#endif

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static bool MpGetInfo()
{
	// Try to find the RSDP in the BIOS
	void* i;
	for(i = PTOV(0xE0000); i < PTOV(0xFFFFF); i += 16)
	{
		if(memcmp(i, "RSD PTR", 7) == 0)
		{
			if(!AcpiChecksum(i, sizeof(RSDP_t)))
				continue;
			return MpGetInfoAcpi(i);
		}
	}
	
	// Try to find the RSDP in the EBDA
	uint16 ebdaSegment = *((uint16*)PTOV(0x040E));
	for(i = PTOV(ebdaSegment<<4); i < PTOV((ebdaSegment<<4)+0x400); i += 16)
	{
		if(memcmp(i, "RSD PTR", 7) == 0)
		{
			if(!AcpiChecksum(i, sizeof(RSDP_t)))
				continue;
			return MpGetInfoAcpi(i);
		}
	}
	
	return false;
}
static bool MpGetInfoAcpi(RSDP_t* rsdp)
{
	// Use the RSDP to find the RSDT
	RSDT_t* rsdt = (RSDT_t*)PTOV(rsdp->RsdtAddress);
	if(!AcpiChecksum(rsdt, rsdt->Length))
		return false;
	
	// Iterate through the tables to find the MADT
	MADT_t* madt;
	int tableCount = (rsdt->Length-sizeof(RSDT_t))/4;
	int i;
	for(i = 0; i < tableCount; i++)
	{
		madt = (MADT_t*)PTOV(*(((uint32*)(rsdt+1))+i));
		if(memcmp(madt, "APIC", 4) == 0)
			break;
	}
	if(i == tableCount) // If we didn't find the MADT, something screwed up
		return false;
	if(!AcpiChecksum(madt, madt->Length)) // Checksum the MADT
		return false;
	
	// Get the number of processors and IO APICs
	MpProcessorCount = 0;
	for(MADTSubtable_t* sub = (MADTSubtable_t*)(madt+1); (void*)sub < ((void*)madt)+madt->Length; sub = (MADTSubtable_t*)(((void*)sub)+sub->Length))
	{
		if(sub->Type == MADT_LAPIC)
			MpProcessorCount++;
	}
	if(MpProcessorCount < 1) // There needs to be at least one processor and one IO APIC
		return false;
		
	// Allocate processor table
	MpProcessorTable = (Processor_t*)MemoryAllocPages(ALIGN_SMALL(sizeof(Processor_t)*MpProcessorCount)/PAGE_SIZE_SMALL, VALLOC_MASK_FLAG_WRITABLE);
	if((virt_addr)MpProcessorTable == INVALID_VIRTUAL_ADDRESS)
		return false;
	
	// Fill the processor and IO APIC tables
	i = 0;
	for(MADTSubtable_t* sub = (MADTSubtable_t*)(madt+1); (void*)sub < ((void*)madt)+madt->Length; sub = (MADTSubtable_t*)(((void*)sub)+sub->Length))
	{
		if(sub->Type == MADT_LAPIC)
		{
			MpProcessorTable[i].LapicId = ((AcpiLapic_t*)sub)->LapicId;
			i++;
		}
	}
	
	return true;
}

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return (accum == 0);

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for(i = PTOV(0xE0000); i < PTOV(0xFFFFF); [b]i += 16[/b])

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if(!AcpiChecksum(rsdt, rsdt->Length))
      return false;

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if(AcpiChecksum(rsdt, rsdt->Length) == 0)
     return false;

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if(!AcpiChecksum(rsdt, rsdt->Length))
     return false;

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typedef struct RSDTable
{
   	char Signature[4];
   	int Length;
   	char Revision;
   	char Checksum;
   	char OemId[6];
   	char OemTableId[8];
   	char OemRevision[4];
   	char CreatorId[4];
   	int CreatorRevision;
}RSDT_t;

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RSDP_t *rsdp;	// Structure to hold the RSDP table, defined in k_acpi_tables.h	
	RSDT_t *rsdt;	// Structure to hold the RSDT structure

	// Searching for RSDP in 16 byte boundaries
	if((rsdp = acpi_find_rsdp())==0)
		k_printf("No multiple CPUs", 7);
	else
	{
		// So RSDP has been found.. now what? --> checksum!!
		
		
		if(acpi_checksum(rsdp,rsdp->Length)!=1)
		{
			k_printf("RSDP checksum failed..",7);
		}
		else
		{
			k_printf("RSDP found!",7);

			// parse RSDT.. but first checksum!
			rsdt = (RSDT_t*)(rsdp->RsdtAddress);

			if(mystrcmp((char*)rsdt,"RSDT",4)== 1)
				k_printf("Signature Match",8);

			if(acpi_checksum(rsdt,rsdt->Length)!=1)
				k_printf("RSDT checksum failed",9);
			else
			{
				k_printf("RSDT Found!",9);
			}				
			
		}
		
	}