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#pragma once
#define VCPU_FREQ 600
#define DTST_FREQ 60
#define SCREEN_FREQ 60
#define REG_FLAG 0xF
/**
* @brief Store the entire VCPU state
*
*/
typedef struct VCPU_State {
/// @brief Program Counter (16 bits but only 12 bits used (4096 memory addresses))
unsigned short PC;
/// @brief Index register (16 bits but only 12 bits used (4096 memory addresses))
unsigned short I;
/// @brief Stack register (16 bits)
unsigned short S;
unsigned short stack[100]; // Emulated stack
/// @brief General purpose registers (8 bits each)
unsigned char V[16]; // Note last one often used as a flag register
/// @brief Delay timer (8 bits)
unsigned char DT;
/// @brief Sound timer (8 bits)
unsigned char ST;
/// @brief Intruction (opcode + decoded fields)
unsigned short opcode;
unsigned char X;
unsigned char Y;
unsigned char N;
unsigned char NN;
unsigned short NNN;
/// @brief Keypressed
int keypressed; // Not 0 if a key was pressed
unsigned char key;
/// @brief Count VCPU ticks
int dt_ticks;
int st_ticks;
int screen_ticks;
} VCPU_State;
/**
* @brief Must be called first!
*
*/
void VCPUInit(int width, int height);
/**
* @brief Fetch instruction from memory
*
*/
void VCPUFetch();
/**
* @brief Decode instruction from the last fetch
*
*/
void VCPUDecode();
/**
* @brief Execute decode instruction
*
*/
void VCPUExecute();
/**
* @brief Fetch, decode and execute an instruction
*
*/
void VCPUTick();
/**
* @brief Simple (a bit) binary to BCD convertion
*
* @param x
* @param u
* @param t
* @param h
*/
void VCPUDoubleDabble(unsigned char x, unsigned char *u, unsigned char *t, unsigned char *h);
/**
* @brief Dump VCPU state
*
*/
void VCPUDump();
/**
* @brief To call before terminating the application
*
*/
void VCPUFinish();
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