// SPDX-License-Identifier: WTFPL
// original idea: https://nanacchig7.blogspot.com/2026/03/msx.html
// zcc +msx -subtype=msxdos nana-20260302.c -o nana0302.com

#include <stdio.h>
#include <msx.h>

#define PCG_TABLE 0x0000

static void init_screen(void)
{
	unsigned char i;

	// screen 1
	// color 15, 4, 7

	for (i = 0; i < 224; i++)
		putchar(i + 32);
}

static void modify_font(unsigned char *d)
{
	int i, j;
	unsigned char p, q, r, s;

	for (i = 0; i < 8; i++) {
		p = 0xa0;
		q = 0x80;
		r = 0x40;
		s = 0x00;

		for (j = 0; j < 6; j++) {
			if ((*d & p) == q) s |= r;
			p >>= 1;
			q >>= 1;
			r >>= 1;
		}

		*d++ |= s;
	}
}

static void modify_chars(void)
{
	unsigned char i;
	unsigned char d[8];

	for (i = 0; i < 224; i++) {
		msx_vread(PCG_TABLE + (i + 32) * 8 + j, d, 8);
		modify_font(d);
		msx_vwrite(d, PCG_TABLE + (i + 32) * 8 + j, 8);
	}
}

int main(int argc, char *argv[])
{
	init_screen();
	modify_chars();

	return 0;
}