#include <stdlib.h>
#include <string.h>

#include "cv.h"
#include "cvu.h"

#define COLOR ((const cv_vmemp)0x2000)
#define IMAGE ((const cv_vmemp)0x1c00)

#define COLS 32
#define ROWS 24

typedef unsigned char byte;
typedef signed char sbyte;
typedef unsigned short word;

uintptr_t __at(0x6a) font_bitmap_a;
uintptr_t __at(0x6c) font_bitmap_0;

volatile bool vint;
volatile uint_fast8_t vint_counter;

void vint_handler(void)
{
  vint = true;
  vint_counter++;
}

void setup_32_column_font() {
  cv_set_image_table(IMAGE);
  cvu_memtovmemcpy(0x1800, (void *)(font_bitmap_0 - '0'*8), 256*8);
  cv_set_character_pattern_t(0x1800);
  cv_set_screen_mode(CV_SCREENMODE_STANDARD);
  cv_set_color_table(COLOR);
  cvu_vmemset(COLOR, 0x36, 8); // set color for chars 0-63
  cvu_vmemset(COLOR+8, 0x06, 32-8); // set chars 63-255
}

char cursor_x;
char cursor_y;

void clrscr() {
  cvu_vmemset(IMAGE, ' ', COLS*ROWS);
}

#define LOCHAR 0x0
#define HICHAR 0xff

#define CHAR(ch) (ch-LOCHAR)

byte getchar(byte x, byte y) {
  return cvu_vinb(IMAGE + y*COLS + x);
}

void putchar(byte x, byte y, byte attr) {
  cvu_voutb(attr, IMAGE + y*COLS + x);
}

void putstring(byte x, byte y, const char* string) {
  while (*string) {
    putchar(x++, y, CHAR(*string++));
  }
}

void wait_vsync() {
  vint = false;
  while (!vint) ;
}

void delay(byte i) {
  while (i--) {
    wait_vsync();
  }
}

void main() {
  setup_32_column_font();
  cv_set_screen_active(true);
  cv_set_vint_handler(&vint_handler);

  while(1);
}