/*-------------------------------------------------------------------
**
**  Soluciones del examen de Programación de Sistemas y Dispositivos
**  Curso 2021-22, Primera Convocatoria, 19 de enero de 2022
**
**-----------------------------------------------------------------*/

/*-------------------------------------------------------------------
**    Ejercicio 1
**-----------------------------------------------------------------*/

#include <s3c44b0x.h>
#include <common_types.h>
#include <system.h>
#include <timers.h>

#define TICKS_PER_SEC   (1000)

/* Declaración de fifo de punteros a funciones */

#define BUFFER_LEN   (512)

typedef void (*pf_t)(void);

typedef struct fifo {
    uint16 head;
    uint16 tail;
    uint16 size;
    pf_t buffer[BUFFER_LEN];
} fifo_t;

void fifo_init( void );
void fifo_enqueue( pf_t pf );
pf_t fifo_dequeue( void );
boolean fifo_is_empty( void );
boolean fifo_is_full( void );

/* Declaración de recursos */

volatile fifo_t fifo;

/* Declaración de tareas */

void Task1( void );
void Task2( void );
void Task3( void );

/* Declaración de RTI */

void isr_tick( void ) __attribute__ ((interrupt ("IRQ")));

void main( void )
{
    pf_t pf;

    sys_init();
    timers_init();

    fifo_init(); 
    timer0_open_tick( isr_tick, TICKS_PER_SEC );

    while( 1 )
    {
        while( !fifo_is_empty() )
        {
            pf = fifo_dequeue();
            (*pf)();
        }
    }
}

void isr_tick( void )
{
    static uint8 cont10ticks = 10;
    static uint8 cont20ticks = 20;
    static uint8 cont30ticks = 30;

    if( !(--cont10ticks) )
    {
        cont10ticks = 10;
        fifo_enqueue( Task1 );
    }
    if( !(--cont20ticks) )
    {
        cont20ticks = 20;
        fifo_enqueue( Task2 );
    }
    if( !(--cont30ticks) )
    {
        cont30ticks = 30;
        fifo_enqueue( Task3 );
    }
    I_ISPC = BIT_TIMER0;
}


/*-------------------------------------------------------------------
**    Ejercicio 2
**-----------------------------------------------------------------*/

#include <common_types.h>
#include <lcd.h>

extern uint8 font[];

void lcd_putchar_upsidedown( uint16 x, uint16 y, uint8 color, char ch )
{
    uint8 line, row;
    uint8 *bitmap;

    bitmap = font + ch*16;
    for( line=0; line<16; line++ )
        for( row=0; row<8; row++ )
            if( bitmap[line] & (0x80 >> row) )
                lcd_putpixel( x+7-row, y+15-line, color );
            else
                lcd_putpixel( x+7-row, y+15-line, WHITE );
}

/*-------------------------------------------------------------------
**    Ejercicio 3
**-----------------------------------------------------------------*/

#include <s3c44b0x.h>
#include <common_types.h>
#include <lcd.h>

extern uint8 lcd_buffer[];

void lcd_snapshot( uint8 action, uint8 *capture )
{
    uint32 srcAddr, dstAddr;

    if( action ){
        srcAddr = (uint32) lcd_buffer;
        dstAddr = (uint32) capture;
    } else {
        srcAddr = (uint32) capture;
        dstAddr = (uint32) lcd_buffer;
    }
    ZDISRC0 = (2 << 30) | (1 << 28) | srcAddr;            // datos de 32b, dirección post-incrementada
    ZDIDES0 = (2 << 30) | (1 << 28) | dstAddr;            // recomendada, dirección post-incrementada
    ZDICNT0 = (2 << 28) | (1 << 26) | LCD_BUFFER_SIZE;    // whole service, unit transfer, polling mode, no autoreload
    ZDICNT0 |= (1 << 20);                                 // Enable DMA (según manual debe hacerse en escritura separada a la escritura del resto de registros)
    ZDCON0  = 1;                                          // start DMA
}

/*-------------------------------------------------------------------
**    Ejercicio 4
**-----------------------------------------------------------------*/

#include <s3c44b0x.h>
#include <common_types.h>
#include <iis.h>
#include <timers.h>

#define FS (16000)

void isr_timer0( void ) __attribute__ ((interrupt ("IRQ")));

uint16 counter, toggleWave;

void iss_buzz( uint16 freqHz )
{
    if( freqHz ) {
        counter = 0;
        toggleWave = FS / (2*freqHz);
        timer0_open_tick( isr_timer0, FS );
    }
    else
        timer0_close();
}

void isr_timer0( void )
{
    static int16 sample = MAX_INT16;

    if( ++counter == toggleWave ){
        counter = 0;
        sample = -sample;
    }
    iis_putSample( sample, sample );
    I_ISPC = BIT_TIMER0;
}