/*-------------------------------------------------------------------
**
**  Soluciones del examen de Programación de Sistemas y Dispositivos
**  Curso 2022-23, Primera Convocatoria, 18 de enero de 2023
**
**-----------------------------------------------------------------*/

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

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

#define MAXLEN 100

void timer0_isr( void ) __attribute__ ((interrupt ("IRQ")));

volatile boolean flag;
volatile char s[MAXLEN];

void main( void )
{  
    sys_init();
    uart0_init();
    timers_init();

    flag = FALSE;
    timer0_open_ms( timer0_isr, 20, TIMER_INTERVAL );
    while( 1 )
        if( flag )
        {
            uart0_puts( s );
            flag = FALSE;
        }
}

void timer0_isr( void )
{
    static char *p = s;
    char ch;
    
    if( UFSTAT0 & 0xF )
    {
        ch = URXH0;
        *p++ = ch;
        if( ch == '\n' )
        {
            *p = '\0';
            p = s;
            flag = TRUE;
        }
    }
    I_ISPC = BIT_TIMER0;
}

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

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

extern uint8 lcd_buffer[];

void lcd_putWindow( uint8 *bmp, uint16 xleft, uint16 yup, uint16 xright, uint16 ydown )
{
    uint32 headerSize;

    uint16 x, ySrc, yDst;
    uint16 offsetSrc, offsetDst;

    headerSize = bmp[10] + (bmp[11] << 8) + (bmp[12] << 16) + (bmp[13] << 24);

    bmp = bmp + headerSize;

    for( ySrc=LCD_HEIGHT-ydown, yDst=ydown-1; ySrc<LCD_HEIGHT-yup; ySrc++, yDst-- )
    {
        offsetDst = yDst*LCD_WIDTH/2;
        offsetSrc = ySrc*LCD_WIDTH/2;
        for( x=xleft/2; x<xright/2; x++ )
            lcd_buffer[offsetDst+x] = ~bmp[offsetSrc+x];
    }
}

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

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

void memcpy_dma( uint8 *dest, uint8 *src, uint16 n )
{
   
    ZDISRC0  = (0 << 30) | (1 << 28) | (uint32) src;     // datos de 8b, dirección post-incrementada, origen: src
    ZDIDES0  = (2 << 30) | (1 << 28) | (uint32) dest;    // recomendada, dirección post-incrementada, destino: dest
    ZDICNT0  = (2 << 28) | (1 << 26) | n;                // tamaño: n
    ZDICNT0 |= (1 << 20);                                // enable DMA (según manual debe hacerse en escritura separada a la escritura del resto de registros)
    ZDCON0   = 1;                                        // start DMA     
    while( ZDCCNT0 & 0xFFFFF );                          // espera a que termine la transferencia DMA
}


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


#define LCD_COLS   (LCD_WIDTH/2)
#define LCD_ROWS   (LCD_HEIGHT)

extern uint8 lcd_buffer[];

void lcd_vflip( void )
{
    uint8 rowAux[LCD_COLS];
    uint8 *rowA, *rowB;
    uint16 ySrc, yDst;

    for( ySrc=0, yDst=LCD_HEIGHT-1; ySrc<=LCD_ROWS/2; ySrc++, yDst-- )
    {
        rowA = lcd_buffer + ySrc*LCD_COLS;
        rowB = lcd_buffer + (yDst-1)*LCD_COLS;

        memcpy_dma( rowAux, rowA,   LCD_COLS );    // rowAux <- rowA
        memcpy_dma( rowA,   rowB,   LCD_COLS );    // rowA   <- rowB
        memcpy_dma( rowB,   rowAux, LCD_COLS );    // rowB   <- rowAux
    }
}