#include <LPC17xx.h>

#define RS_CTRL 0x08000000
#define EN_CTRL 0x10000000
#define DT_CTRL 0x07800000

unsigned int col = 0;
unsigned long int temp1 = 0, temp2 = 0, i, j;
unsigned char flag1 = 0, flag2 = 0;
unsigned char msg[] = ("Long messages work well, heh.");

void lcd_write(void);
void port_write(void);
void delay_lcd(unsigned long);

unsigned long int init_command[] = {
    0x30, 0x30, 0x30, 0x20, 0x28, 0x0C, 0x01, 0x80
};

#define LCD_COLS 16

int main() {
    LPC_GPIO0->FIODIR = DT_CTRL | RS_CTRL | EN_CTRL;

    flag1 = 0;

    
    for (i = 0; i < 8; i++) {
        temp1 = init_command[i];
        lcd_write();
    }

    
    flag1 = 1;

    
    i = 0;

    while (msg[i] != '\0') {
        if (col == LCD_COLS) {
            flag1 = 0;
            temp1 = 0xC0;
            lcd_write();

            flag1 = 1;
        } else if (col == (LCD_COLS * 2)) {
            flag1 = 0;
            temp1 = 0x80;
            lcd_write();

            flag1 = 1;
            col = 0;
        }

        temp1 = msg[i++];
        lcd_write();
        col++;
    }

    while (1)
        ;
}

void lcd_write(void) {
    flag2 = (flag1 == 1) ? 0 :
            (((temp1 == 0x30) || (temp1 == 0x20)) ? 1 : 0);

    temp2 = temp1 & 0xf0;
    temp2 = temp2 << 19;

    port_write();

    if (!flag2) {
        temp2 = temp1 & 0x0f;
        temp2 = temp2 << 23;
        port_write();
    }
}

void port_write(void) {
    LPC_GPIO0->FIOPIN = temp2;

    if (flag1 == 0) {
        LPC_GPIO0->FIOCLR = RS_CTRL;
    } else {
        LPC_GPIO0->FIOSET = RS_CTRL;
    }

    LPC_GPIO0->FIOSET = EN_CTRL;
    delay_lcd(100);
    LPC_GPIO0->FIOCLR = EN_CTRL;

    delay_lcd(500000);
}

void delay_lcd(unsigned long r1) {
    unsigned long r;

    for (r = 0; r < r1; r++)
        ;
    return;
}