#include "f256.h"


char error;


#define MAX_COL  80
#define MAX_ROW  60


static char  row  = 0;
static char  col  = 0;
static char *line = (char *)TEXT_MATRIX;


void cls(void) {
	int   i;
	char *vram = (char *)TEXT_MATRIX;
	unsigned char mmu;

	mmu = PEEK(MMU_IO_CTRL);  // Get current MMU state.
	POKE(MMU_IO_CTRL, 2);     // Swap I/O page 2 into bank 6.

	for (i = 0; i < 80*60; i++) {
		*vram++ = 32;
	}

	row = col = 0;
	line = (char *)TEXT_MATRIX;

	POKE(MMU_IO_CTRL, mmu);  // Restore MMU state.

	POKE(CURSOR_SETTINGS, 9);  // Disable cursor flash.
	POKE(CURSOR_CHARACTER, '_');  // Set cursor shape.

	POKE(CURSOR_X_LOW, col);  // Set cursor X position.
	POKE(CURSOR_X_HIGH, 0);

	POKE(CURSOR_Y_LOW, row);  // Set cursor Y position.
	POKE(CURSOR_Y_HIGH, 0);

	POKE(0xd011, 0);
}


static void scroll() {
	int i;
	char *vram = (char *)TEXT_MATRIX;

	for (i = 0; i < 80*59; i++) {
		vram[i] = vram[i+80];
	}
	vram += i;
	for (i = 0; i < 80; i++) {
		*vram++ = 32;
	}
}


void print(char *message) {
	int x = 0;
	unsigned char mmu;

	mmu = PEEK(MMU_IO_CTRL);  // Get current MMU state.
	POKE(MMU_IO_CTRL, 2);     // Swap I/O page 2 into bank 6.

	while (message[x] != 0) {
		switch (message[x]) {
			default:
				line[col] = message[x];
				col++;
				if (col != MAX_COL) {
					break;
				}
				// Fall through.
			case 10:
			case 13:
				col = 0;
				row++;
				if (row == MAX_ROW) {
					scroll();
					row--;
					break;
				}
				line += 80;
				break;
		}
		x++;
	}

	POKE(MMU_IO_CTRL, mmu);  // Restore MMU state.

	POKE(CURSOR_X_LOW, col);
	POKE(CURSOR_Y_LOW, row);
}