[#] DR7 Register

#include <stdio.h>
#include <Windows.h>

#define EXECUTE_COND        0
#define WRITE_COND          1
#define IO_READWRITE_COND   2
#define READWRITE_COND      3

#define SIZE_BYTE  0
#define SIZE_WORD  1
#define SIZE_DWORD 3
#define SIZE_QWORD 2

// Debug Register 7 field
typedef struct _DR_CONTROL_BIT
{
	unsigned long Dr0_LocalBp : 1;           // 00 (1)
	unsigned long Dr0_GlobalBp : 1;          // 01 (1)
	unsigned long Dr1_LocalBp : 1;           // 02 (1)
	unsigned long Dr1_GlobalBp : 1;          // 03 (1)
	unsigned long Dr2_LocalBp : 1;           // 04 (1)
	unsigned long Dr2_GlobalBp : 1;          // 05 (1)
	unsigned long Dr3_LocalBp : 1;           // 06 (1)
	unsigned long Dr3_GlobalBp : 1;          // 07 (1)
	unsigned long LocalExactBp : 1;          // 08 (1)
	unsigned long GlobalExactBp : 1;         // 09 (1)
	unsigned long Reserved_0 : 3;            // 10 (3)
	unsigned long GeneralDetectEnable : 1;   // 13 (1)
	unsigned long Reserved_1 : 2;            // 14 (2)
	unsigned long Dr0_Control : 2;           // 16 (2)
	unsigned long Dr0_Size : 2;              // 18 (2)
	unsigned long Dr1_Control : 2;           // 20 (2)
	unsigned long Dr1_Size : 2;              // 22 (2)
	unsigned long Dr2_Control : 2;           // 24 (2)
	unsigned long Dr2_Size : 2;              // 26 (2)
	unsigned long Dr3_Control : 2;           // 28 (2)
	unsigned long Dr3_Size : 2;              // 30 (2)
	unsigned long Dummy;                     // 32 (32)

}DR_CONTROL_BIT, * PDR_CONTROL_BIT;


BOOLEAN CreateException(PVOID pTarget, PCONTEXT context, PDR_CONTROL_BIT ControlFlag, DWORD Condition, DWORD Size)
{
	int count = 0;
	for (int i = 0; i < 4; i++)
	{
		if (*((&context->Dr0) + i) != 0)
		{
			count++;
			continue;
		}
		else
		{
			*((&context->Dr0) + i) = (DWORD64)pTarget;
			count++;
			switch (count)
			{
			case 1:
				ControlFlag->Dr0_LocalBp = 1;
				ControlFlag->Dr0_Control = Condition;
				ControlFlag->Dr0_Size = Size;
				return TRUE;

			case 2:
				ControlFlag->Dr1_LocalBp = 1;
				ControlFlag->Dr1_Control = Condition;
				ControlFlag->Dr1_Size = Size;
				return TRUE;

			case 3:
				ControlFlag->Dr2_LocalBp = 1;
				ControlFlag->Dr2_Control = Condition;
				ControlFlag->Dr2_Size = Size;
				return TRUE;

			case 4:
				ControlFlag->Dr3_LocalBp = 1;
				ControlFlag->Dr3_Control = Condition;
				ControlFlag->Dr3_Size = Size;
				return TRUE;
			}
			return FALSE;
		}
	}
	return FALSE;
}


int main()
{
	PVOID pVirtual = VirtualAlloc(0, USN_PAGE_SIZE, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);

	CONTEXT ct = { 0, };
	DR_CONTROL_BIT ControlFlag = { 0, };

	ct.ContextFlags = CONTEXT_AMD64 | CONTEXT_DEBUG_REGISTERS;

	CreateException(pVirtual, &ct, &ControlFlag, READWRITE_COND, SIZE_BYTE);
	memcpy(&ct.Dr7, &ControlFlag, 8);
	SetThreadContext(GetCurrentThread(), &ct);
	
	// Exception Code
	int a = 0x1337;
	memcpy(pVirtual, &a, 4);
}