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Rev Author Line No. Line
1 nishi 1 
/* $Id: shiroi.c 1 2024-08-28 08:10:28Z nishi $ */
2 
 
3 
unsigned char inp(unsigned char);
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void outp(unsigned char, unsigned char);
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void write_vram(unsigned short);
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void putchar(char);
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void putstr(char*);
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void scroll_y(void);
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void beep(void);
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void _beep(unsigned long howlong);
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void init_cards(void);
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unsigned short posx;
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unsigned short posy;
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short vdp_addr;
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short vdp_data;
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short psg_addr;
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short psg_data;
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short fpu_addr;
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short fpu_data;
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void main(void) {
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	int i;
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	posx = 0;
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	posy = 0;
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	vdp_addr = -1;
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	psg_addr = -1;
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	fpu_addr = -1;
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	init_cards();
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	if(vdp_addr == -1) {
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		int i;
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		for(i = 0; i < 3; i++) {
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			_beep(3L * 1024);
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			unsigned long j;
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			for(j = 0; j < 3L * 1024; j++)
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				;
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		}
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		while(1)
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			;
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	}
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	outp(vdp_addr, 0x00);
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	outp(vdp_addr, 0x80);
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	outp(vdp_addr, 0xd0);
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	outp(vdp_addr, 0x81);
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	outp(vdp_addr, 0x02);
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	outp(vdp_addr, 0x82);
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	outp(vdp_addr, 0x00);
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	outp(vdp_addr, 0x84);
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	outp(vdp_addr, 0xf4);
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	outp(vdp_addr, 0x87);
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	write_vram(0);
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	for(i = 0; i < 0x800; i++) outp(vdp_data, *((unsigned char*)(0x2000 + i)));
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	beep();
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	putstr("Shiroi Microcomputer BASIC\r\n");
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	if(fpu_addr == -1) {
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		putstr("Math Card Mark I not present\r\n");
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	} else {
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		putstr("Math Card Mark I present\r\n");
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	}
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	if(psg_addr == -1) {
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		putstr("Sound Card Mark I not present\r\n");
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	} else {
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		putstr("Sound Card Mark I present\r\n");
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	}
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	write_vram(0x800 + 40 * 12);
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	for(i = 0; i < 0x100; i++) outp(vdp_data, i);
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	while(1)
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		;
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}
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void init_cards(void) {
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	int i;
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	int port = 2;
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	for(i = 0; i < 256 / 3; i++) {
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		int t = inp(port);
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		if(t != 0) {
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			if(t == 0x01) {
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				vdp_addr = port - 2;
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				vdp_data = port - 1;
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			} else if(t == 0x11) {
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				psg_addr = port - 2;
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				psg_data = port - 1;
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			} else if(t == 0x21) {
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				fpu_addr = port - 2;
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				fpu_data = port - 1;
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			}
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		}
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		port += 3;
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	}
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}
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void beep(void) { _beep(3L * 1024); }
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void _beep(unsigned long howlong) {
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	if(psg_addr == -1) return;
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	unsigned long i;
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	outp(psg_addr, 8);
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	outp(psg_data, 0x0f);
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	outp(psg_addr, 0);
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	outp(psg_data, 0xd6);
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	outp(psg_addr, 1);
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	outp(psg_data, 0x0);
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	outp(psg_addr, 7);
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	outp(psg_data, 0x3e);
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	for(i = 0; i < howlong; i++)
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		;
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	outp(psg_addr, 7);
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	outp(psg_data, 0x3f);
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}
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void write_vram(unsigned short addr) {
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	addr |= 0x4000;
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	outp(vdp_addr, addr & 0x00ff);
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	outp(vdp_addr, ((addr & 0xff00) >> 8));
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}
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void read_vram(unsigned short addr) {
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	outp(vdp_addr, addr & 0x00ff);
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	outp(vdp_addr, ((addr & 0xff00) >> 8));
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}
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143 
void scroll_y(void) {
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	int i;
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	for(i = 0; i < 40 * 23; i++) {
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		read_vram(0x800 + i + 40);
147 
		unsigned char ch = inp(vdp_data);
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		write_vram(0x800 + i);
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		outp(vdp_data, ch);
150 
	}
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	for(i = 0; i < 40; i++) {
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		outp(vdp_data, 0);
153 
	}
154 
}
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156 
void putchar(char c) {
157 
	if(c == '\r') {
158 
		posx = 0;
159 
	} else if(c == '\n') {
160 
		posy++;
161 
	} else {
162 
		write_vram(0x800 + posy * 40 + posx);
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		outp(vdp_data, c);
164 
		posx++;
165 
		if(posx == 40) {
166 
			posx = 0;
167 
			posy++;
168 
		}
169 
	}
170 
	if(posy == 24) {
171 
		scroll_y();
172 
		posy = 23;
173 
		posx = 0;
174 
	}
175 
}
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177 
void putstr(char* str) {
178 
	int i;
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	for(i = 0; str[i] != 0; i++) putchar(str[i]);
180 
}
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182 
unsigned char inp(unsigned char port) __naked { __asm ld hl, #2 add hl, sp ld c, (hl)in a, (c)ld l, a ld h, #0 ret __endasm; }
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void outp(unsigned char port, unsigned char data) __naked { __asm push bc ld hl, #4 add hl, sp ld c, (hl)inc hl ld b, (hl)out(c), b pop bc ret __endasm; }