/*
 Program 
 This needs to be built with the board package of MBedOS 
 (Arduino MbedOS RP2040 boards --> Raspberry Pi Pico
 If you try to upload this program with other Pico board choices, 
 the board will become unresponsive.
 CAUTION1: You need to follow the steps that you did when you
 connected the new board for the first time (pressing BOOTSEL)
 whenever the program becomes unresponsive  because of wrong 
 assembly programs  which may hang the board due to some 
 errors in your program.
*/
#include<stdio.h>
#include<stdlib.h>

// Uncomment this if when you copy this code to run it on HW
//#define RUN_ON_HW

#ifdef RUN_ON_HW
#define Serial1 Serial
#endif

void myPrint(char* fnName, unsigned int result);

// Define external assembly function
extern "C" {
  unsigned int my_asm_fn(void);
}

// the setup function runs once when you press reset or power the board
void setup() {
  // Initialize serial communication
  Serial1.begin(9600);
  // Initialize built-in LED pin as an output
  pinMode(LED_BUILTIN, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  unsigned int asm_ret_val;

  // Call the assembly function and receive the result in R3
  asm_ret_val = my_asm_fn();
  
  // Print the result returned from the assembly function
  myPrint("my_asm_fn()", asm_ret_val);

  // Blink the built-in LED
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
} // end of loop()

// Print function to display results
void myPrint(char* fnName, unsigned int printVal) {
  Serial1.print("The value returned from the assembly fn ");
  Serial1.print(fnName);
  Serial1.print(" : ");
  Serial1.println(printVal);

  Serial1.print("The value returned from the assembly fn ");
  Serial1.print(fnName);
  Serial1.print(" in Hex: 0x");
  Serial1.println(printVal, HEX);
} // myPrint(char*, int)