C02/vic20/pointers.c02

/************************************
 * POINTERS - Test pointer.h02 Library *
 ************************************/
 
#include "include/vic20.h02"
#include <stdio.h02>
#include <pointer.h02>

char savelo, savehi; //Pointer Storage Variable
char ptemp;  //Memory Marker for Compare 

main:
  //Set Pointer to Cassette Buffer
  putstr("SET POINTER TO TBFFR");
  ptrset(&tbffr);
  prpntr();
  newlin();
  
  //Demonstrate Compare
  putstr("COMPARE AGAINST");
  outstr(" TEMP0 $");
  prbyte(ptrcmp(&temp0)); newlin();
  outstr(" TBFFR $");
  prbyte(ptrcmp(&tbffr)); newlin();
  outstr(" PTEMP $");
  prbyte(ptrcmp(&ptemp)); newlin();
  newlin();
  
  anykey();
  
  //Demonstrate Get, Put, Inc, and Dec
  putstr("PUT '*' AT POINTER");
  ptrput('*');
  prpntr();
  putstr("DECREMENT POINTER");
  ptrdec();
  prpntr();
  outstr("GOT FROM POINTER: ");
  putchr(ptrget());
  newlin();
  prpntr();
  putstr("INCREMENT POINTER");
  ptrinc();
  prpntr();
  newlin();
  
  //Demonstrate Add and Subtract
  putstr("ADD $FF TO POINTER");
  ptradd($FF);
  prpntr();
  putstr("SUBTRACT $FF");
  ptrsub($FF);
  prpntr();
  newlin();
  
  anykey();
  
  //Demonstrate Save and Restore
  putstr("SAVE POINTER");
  savelo = ptrlo; savehi = ptrhi;
  putstr("CLEAR POINTER");
  ptrlo = 0; ptrhi = 0;
  prpntr();
  putstr("RESTORE FROM PSAVE");
  ptrlo = savelo; ptrhi = savehi;
  prpntr();
  
  goto exit;

  
//Print Pointer Contents
void prpntr() {
  outstr(" POINTER IS NOW ");
  prbyte(ptrhi); 
  prbyte(ptrlo); 
  newlin();
}

//Wait for Keypress
void anykey() {
  putstr("PRESS ANY KEY...");
  getchr();
  newlin();
  newlin();
}