MAME SVN History

199869 Revisions

r33742 Monday 8th December, 2014 at 17:48:11 UTC by Curt Coder
fdc_pll: Added write_next_bit_prev_cell() that writes a bit at the position the previous bit was read from. This is needed for FDC's that read and write on the same clock cycle, e.g. the Commodore 8050 and Victor 9000. [Curt Coder]

[src/emu/machine]	fdc_pll.c fdc_pll.h
[src/mess/machine]	victor9k_fdc.c

trunk/src/emu/machine/fdc_pll.c
r242253	r242254
22	22	void fdc_pll_t::reset(const attotime &when)
23	23	{
24	24	ctime = when;
	25	write_ctime = when;
25	26	phase_adjust = attotime::zero;
26	27	freq_hist = 0;
27	28	write_position = 0;
r242253	r242254
65	66	if(next > limit)
66	67	return -1;
67	68
	69	write_ctime = ctime;
68	70	ctime = next;
69	71	tm = next;
70	72
r242253	r242254
130	132	ctime = etime;
131	133	return false;
132	134	}
	135
	136	bool fdc_pll_t::write_next_bit_prev_cell(bool bit, attotime &tm, floppy_image_device *floppy, const attotime &limit)
	137	{
	138	if(write_start_time.is_never()) {
	139	write_start_time = write_ctime;
	140	write_position = 0;
	141	}
	142
	143	attotime etime = write_ctime + period;
	144	if(etime > limit)
	145	return true;
	146
	147	if(bit && write_position < ARRAY_LENGTH(write_buffer))
	148	write_buffer[write_position++] = write_ctime + period/2;
	149
	150	return false;
	151	}

trunk/src/emu/machine/fdc_pll.h
r242253	r242254
12	12	public:
13	13	attotime ctime, period, min_period, max_period, period_adjust_base, phase_adjust;
14	14
	15	attotime write_ctime;
15	16	attotime write_start_time;
16	17	attotime write_buffer[32];
17	18	int write_position;
r242253	r242254
21	22	void reset(const attotime &when);
22	23	int get_next_bit(attotime &tm, floppy_image_device *floppy, const attotime &limit);
23	24	bool write_next_bit(bool bit, attotime &tm, floppy_image_device *floppy, const attotime &limit);
	25	bool write_next_bit_prev_cell(bool bit, attotime &tm, floppy_image_device *floppy, const attotime &limit);
24	26	void start_writing(const attotime &tm);
25	27	void commit(floppy_image_device *floppy, const attotime &tm);
26	28	void stop_writing(floppy_image_device *floppy, const attotime &tm);

trunk/src/mess/machine/victor9k_fdc.c
r242253	r242254
1114	1114
1115	1115	bool victor_9000_fdc_t::pll_write_next_bit(bool bit, attotime &tm, floppy_image_device *floppy, const attotime &limit)
1116	1116	{
1117		return cur_pll.write_next_bit(bit, tm, floppy, limit);
	1117	return cur_pll.write_next_bit_prev_cell(bit, tm, floppy, limit);
1118	1118	}
1119	1119
1120	1120	void victor_9000_fdc_t::checkpoint()

199869 Revisions