timer.c

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/*****************************************************************************
 * ugBASIC - an isomorphic BASIC language compiler for retrocomputers        *
 *****************************************************************************
 * Copyright 2021-2026 Marco Spedaletti (asimov@mclink.it)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
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/****************************************************************************
 * INCLUDE SECTION 
 ****************************************************************************/
 
#include "../../ugbc.h"
 
/****************************************************************************
 * CODE SECTION 
 ****************************************************************************/

/* <usermanual>
@keyword TIMER
 
@english
This variable represents a "timer", which is the number of sixtieths / fiftieths 
of a second that have passed since the machine was turned on. This variable, 
when used as a value, measures the elapsed time. However, it can be set to an 
arbitrary value, such as 0, to measure a defined period of time. 
 
The refresh rate of this timer depends on the type of video standard used, 
that is, PAL (50Hz) or NTSC (60Hz).
 
This variable can be abbreviated as ''TI''.
 
@italian
Questa variable rappresenta un "timer", ovvero il numero di sessantesimi / 
cinquantesimi di secondo che sono passati dall'accensione della macchina. 
Questa variabile, se usata come valore, misura il tempo passato. Può essere 
comunque impostata ad un valore arbitrario, come ad esempio 0, per misurare un 
periodo di tempo definito. 
 
La frequenza di aggiornamento di questo timer dipende dal tipo di standard 
video utilizzato, ovvero se PAL (50Hz) oppure NTSC (60Hz).
 
Questa variabile può essere abbreviata come ''TI''.
 
@syntax = TIMER
@syntax TIMER = [50th/60th seconds]
 
@example PRINT TIMER
 
@usedInExample contrib_sierpinski.bas
@usedInExample contrib_sierpinski2.bas
@usedInExample contrib_sierpinski3.bas
 
@seeAlso TI
@target c128
</usermanual> */
/* <usermanual>
@keyword TI
 
@english
 
@italian
 
@alias TIMER
</usermanual> */
Variable * get_timer( Environment * _environment ) {
 
    Variable * result = variable_temporary( _environment, VT_WORD, "(result of get timer)");
 
    char resultAddress[MAX_TEMPORARY_STORAGE]; 
    cpu_move_8bit( _environment, "$A2", result->realName );
    sprintf(resultAddress, "%s", address_displacement(_environment, result->realName, "1") );
    cpu_move_8bit( _environment, "$A1", resultAddress );
    // sprintf(resultAddress, "%s", address_displacement(_environment, result->realName, "2") );
    // cpu_move_8bit( _environment, "$A2", resultAddress );
    
    return result;
    
}

/* <usermanual>
@keyword TIMER
</usermanual> */
 
void set_timer( Environment * _environment, char * _value ) {
 
    Variable * value = variable_retrieve_or_define( _environment, _value, VT_WORD, 0 );
 
    char valueAddress[MAX_TEMPORARY_STORAGE]; 
    cpu_move_8bit( _environment, value->realName, "$A2" );
    sprintf(valueAddress, "%s", address_displacement(_environment, value->realName, "1") );
    cpu_move_8bit( _environment, valueAddress, "$A1" );
    cpu_move_8bit( _environment, "#0", "$A0" );
        
}