For now, the following functions are implemented and working:
void pinMode(uint8_t pin, uint8_t mode);
void digitalWrite(uint8_t pin, uint8_t value);
void digitalToggle(uint8_t Pin);
int digitalRead(uint8_t pin);
void delay(uint32_t milliSeconds);
void Serial_begin(uint32_t baudRate);
void Serial_print(char * string);
void Serial_println(char * string);
void Serial_printnumber(uint32_t number);
uint32_t millis();
uint16_t analogRead(uint8_t channel );
int32_t map(int32_t x, int32_t in_min, int32_t in_max, int32_t out_min, int32_t out_max);