void speaker_sound_device::device_reset()
{
int i;
m_level = 0;
for (i = 0; i < FILTER_LENGTH; i++)
m_composed_volume[i] = 0;
m_composed_sample_index = 0;
m_last_update_time = machine().time();
m_channel_sample_period = HZ_TO_ATTOSECONDS(machine().sample_rate());
m_channel_sample_period_secfrac = ATTOSECONDS_TO_DOUBLE(m_channel_sample_period);
m_interm_sample_period = m_channel_sample_period / RATE_MULTIPLIER;
m_interm_sample_period_secfrac = ATTOSECONDS_TO_DOUBLE(m_interm_sample_period);
m_channel_last_sample_time = m_channel->sample_time();
m_channel_next_sample_time = m_channel_last_sample_time + attotime(0, m_channel_sample_period);
m_next_interm_sample_time = m_channel_last_sample_time + attotime(0, m_interm_sample_period);
m_interm_sample_index = 0;
m_prevx = m_prevy = 0.0;
}
static void configure_screen(crtc6845_state *chip, int postload)
{
if (chip->intf)
{
/* compute the screen sizes */
UINT16 horiz_total = (chip->horiz_total + 1) * chip->intf->hpixels_per_column;
UINT16 vert_total = (chip->vert_total + 1) * (chip->max_ras_addr + 1) + chip->vert_total_adj;
/* determine the visible area, avoid division by 0 */
UINT16 max_x = chip->horiz_disp * chip->intf->hpixels_per_column - 1;
UINT16 max_y = chip->vert_disp * (chip->max_ras_addr + 1) - 1;
/* update only if screen parameters changed, unless we are coming here after loading the saved state */
if (postload ||
(horiz_total != chip->last_horiz_total) || (vert_total != chip->last_vert_total) ||
(max_x != chip->last_max_x) || (max_y != chip->last_max_y))
{
/* update the screen only if we have valid data */
if ((chip->horiz_total > 0) && (max_x < horiz_total) && (chip->vert_total > 0) && (max_y < vert_total))
{
rectangle visarea;
attoseconds_t refresh = HZ_TO_ATTOSECONDS(chip->intf->clock) * (chip->horiz_total + 1) * vert_total;
visarea.min_x = 0;
visarea.min_y = 0;
visarea.max_x = max_x;
visarea.max_y = max_y;
if (LOG) logerror("CRTC6845 config screen: HTOTAL: %x VTOTAL: %x MAX_X: %x MAX_Y: %x FPS: %f\n",
horiz_total, vert_total, max_x, max_y, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
video_screen_configure(chip->intf->scrnum, horiz_total, vert_total, &visarea, refresh);
chip->has_valid_parameters = TRUE;
}
else
chip->has_valid_parameters = FALSE;
chip->last_horiz_total = horiz_total;
chip->last_vert_total = vert_total;
chip->last_max_x = max_x;
chip->last_max_y = max_y;
update_timer(chip);
}
}
}
inline void crt9007_device::recompute_parameters()
{
// check that necessary registers have been loaded
if (!HAS_VALID_PARAMETERS) return;
// screen dimensions
int horiz_pix_total = CHARACTERS_PER_HORIZONTAL_PERIOD * m_hpixels_per_column;
int vert_pix_total = SCAN_LINES_PER_FRAME;
// refresh rate
attoseconds_t refresh = HZ_TO_ATTOSECONDS(clock()) * horiz_pix_total * vert_pix_total;
// horizontal sync
m_hsync_start = 0;
m_hsync_end = HORIZONTAL_SYNC_WIDTH * m_hpixels_per_column;
// visible line time
m_vlt_start = HORIZONTAL_DELAY * m_hpixels_per_column;
m_vlt_end = (HORIZONTAL_DELAY + CHARACTERS_PER_DATA_ROW) * m_hpixels_per_column;
m_vlt_bottom = VERTICAL_DELAY + (VISIBLE_DATA_ROWS_PER_FRAME * SCAN_LINES_PER_DATA_ROW) - 1;
// data row boundary
m_drb_bottom = VERTICAL_DELAY + (VISIBLE_DATA_ROWS_PER_FRAME * SCAN_LINES_PER_DATA_ROW) - SCAN_LINES_PER_DATA_ROW;
// vertical sync
m_vsync_start = 0;
m_vsync_end = VERTICAL_SYNC_WIDTH;
// visible area
rectangle visarea;
visarea.set(m_hsync_end, horiz_pix_total - 1, m_vsync_end, vert_pix_total - 1);
if (LOG)
{
logerror("CRT9007 '%s' Screen: %u x %u @ %f Hz\n", tag(), horiz_pix_total, vert_pix_total, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
logerror("CRT9007 '%s' Visible Area: (%u, %u) - (%u, %u)\n", tag(), visarea.min_x, visarea.min_y, visarea.max_x, visarea.max_y);
}
m_screen->configure(horiz_pix_total, vert_pix_total, visarea, refresh);
m_hsync_timer->adjust(m_screen->time_until_pos(0, 0));
m_vsync_timer->adjust(m_screen->time_until_pos(0, 0));
m_vlt_timer->adjust(m_screen->time_until_pos(0, m_vlt_start), 1);
m_drb_timer->adjust(m_screen->time_until_pos(0, 0));
}
inline void upd3301_device::recompute_parameters()
{
int horiz_pix_total = (m_h + m_z) * m_width;
int vert_pix_total = (m_l + m_v) * m_r;
attoseconds_t refresh = HZ_TO_ATTOSECONDS(clock()) * horiz_pix_total * vert_pix_total;
rectangle visarea;
visarea.set(0, (m_h * m_width) - 1, 0, (m_l * m_r) - 1);
if (LOG)
{
if (LOG) logerror("UPD3301 '%s' Screen: %u x %u @ %f Hz\n", tag(), horiz_pix_total, vert_pix_total, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
if (LOG) logerror("UPD3301 '%s' Visible Area: (%u, %u) - (%u, %u)\n", tag(), visarea.min_x, visarea.min_y, visarea.max_x, visarea.max_y);
}
m_screen->configure(horiz_pix_total, vert_pix_total, visarea, refresh);
update_hrtc_timer(0);
update_vrtc_timer(0);
}
void crtc_ega_device::recompute_parameters(bool postload)
{
UINT16 hsync_on_pos, hsync_off_pos, vsync_on_pos, vsync_off_pos;
/* compute the screen sizes */
UINT16 horiz_pix_total = (m_horiz_char_total + 2) * m_hpixels_per_column;
UINT16 vert_pix_total = m_vert_total + 1;
/* determine the visible area, avoid division by 0 */
UINT16 max_visible_x = ( m_horiz_disp + 1 ) * m_hpixels_per_column - 1;
UINT16 max_visible_y = m_vert_disp_end;
/* determine the syncing positions */
int horiz_sync_char_width = ( m_horiz_retr_end + 1 ) - ( m_horiz_retr_start & 0x1f );
int vert_sync_pix_width = m_vert_retr_end - ( m_vert_retr_start & 0x0f );
if (horiz_sync_char_width <= 0)
horiz_sync_char_width += 0x10;
if (vert_sync_pix_width <= 0)
vert_sync_pix_width += 0x10;
hsync_on_pos = m_horiz_retr_start * m_hpixels_per_column;
hsync_off_pos = hsync_on_pos + (horiz_sync_char_width * m_hpixels_per_column);
vsync_on_pos = m_vert_retr_start; /* + 1 ?? */
vsync_off_pos = vsync_on_pos + vert_sync_pix_width;
if (hsync_off_pos > horiz_pix_total)
hsync_off_pos = horiz_pix_total;
if (vsync_off_pos > vert_pix_total)
vsync_off_pos = vert_pix_total;
if ( vsync_on_pos >= vsync_off_pos )
{
vsync_on_pos = vsync_off_pos - 2;
}
/* update only if screen parameters changed, unless we are coming here after loading the saved state */
if (postload ||
(horiz_pix_total != m_horiz_pix_total) || (vert_pix_total != m_vert_pix_total) ||
(max_visible_x != m_max_visible_x) || (max_visible_y != m_max_visible_y) ||
(hsync_on_pos != m_hsync_on_pos) || (vsync_on_pos != m_vsync_on_pos) ||
(hsync_off_pos != m_hsync_off_pos) || (vsync_off_pos != m_vsync_off_pos))
{
/* update the screen if we have valid data */
if ((horiz_pix_total > 0) && (max_visible_x < horiz_pix_total) &&
(vert_pix_total > 0) && (max_visible_y < vert_pix_total) &&
(hsync_on_pos <= horiz_pix_total) && (vsync_on_pos <= vert_pix_total) &&
(hsync_on_pos != hsync_off_pos))
{
attoseconds_t refresh = HZ_TO_ATTOSECONDS(m_clock) * (m_horiz_char_total + 2) * vert_pix_total;
rectangle visarea(0, max_visible_x, 0, max_visible_y);
if (LOG) logerror("CRTC_EGA config screen: HTOTAL: 0x%x VTOTAL: 0x%x MAX_X: 0x%x MAX_Y: 0x%x HSYNC: 0x%x-0x%x VSYNC: 0x%x-0x%x Freq: %ffps\n",
horiz_pix_total, vert_pix_total, max_visible_x, max_visible_y, hsync_on_pos, hsync_off_pos - 1, vsync_on_pos, vsync_off_pos - 1, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
if ( m_screen != NULL )
m_screen->configure(horiz_pix_total, vert_pix_total, visarea, refresh);
m_has_valid_parameters = true;
}
else
{
m_has_valid_parameters = false;
if (LOG) logerror("CRTC_EGA bad config screen: HTOTAL: 0x%x VTOTAL: 0x%x MAX_X: 0x%x MAX_Y: 0x%x HSYNC: 0x%x-0x%x VSYNC: 0x%x-0x%x\n",
horiz_pix_total, vert_pix_total, max_visible_x, max_visible_y, hsync_on_pos, hsync_off_pos - 1, vsync_on_pos, vsync_off_pos - 1);
}
m_horiz_pix_total = horiz_pix_total;
m_vert_pix_total = vert_pix_total;
m_max_visible_x = max_visible_x;
m_max_visible_y = max_visible_y;
m_hsync_on_pos = hsync_on_pos;
m_hsync_off_pos = hsync_off_pos;
m_vsync_on_pos = vsync_on_pos;
m_vsync_off_pos = vsync_off_pos;
}
}
void speaker_sound_device::device_start()
{
int i;
double x;
m_channel = machine().sound().stream_alloc(*this, 0, 1, machine().sample_rate(), this);
m_level = 0;
for (i = 0; i < FILTER_LENGTH; i++)
m_composed_volume[i] = 0;
m_composed_sample_index = 0;
m_last_update_time = machine().time();
m_channel_sample_period = HZ_TO_ATTOSECONDS(machine().sample_rate());
m_channel_sample_period_secfrac = ATTOSECONDS_TO_DOUBLE(m_channel_sample_period);
m_interm_sample_period = m_channel_sample_period / RATE_MULTIPLIER;
m_interm_sample_period_secfrac = ATTOSECONDS_TO_DOUBLE(m_interm_sample_period);
m_channel_last_sample_time = m_channel->sample_time();
m_channel_next_sample_time = m_channel_last_sample_time + attotime(0, m_channel_sample_period);
m_next_interm_sample_time = m_channel_last_sample_time + attotime(0, m_interm_sample_period);
m_interm_sample_index = 0;
m_prevx = m_prevy = 0.0;
/* Note: To avoid time drift due to floating point inaccuracies,
* it is good if the speaker time synchronizes itself with the stream timing regularly.
*/
/* Compute filter kernel; */
/* (Done for each device though the data is shared...
* No problem really, but should be done as part of system init if I knew how)
*/
#if 1
/* This is an approximated sinc (a perfect sinc makes an ideal low-pass filter).
* FILTER_STEP determines the cutoff frequency,
* which should be below the Nyquist freq, i.e. half the sample rate.
* Smaller step => kernel extends in time domain => lower cutoff freq
* In this case, with sinc, filter step PI corresponds to the Nyq. freq.
* Since we do not get a perfect filter => must lower the cutoff freq some more.
* For example, step PI/(2*RATE_MULTIPLIER) corresponds to cutoff freq = sample rate / 4;
* With -samplerate 48000, cutoff freq is ca 12kHz while the Nyq. freq is 24kHz.
* With -samplerate 96000, cutoff freq is ca 24kHz while the Nyq. freq is 48kHz.
* For a steeper, more efficient filter, increase FILTER_LENGTH at the expense of CPU usage.
*/
#define FILTER_STEP (M_PI / 2 / RATE_MULTIPLIER)
/* Distribute symmetrically on x axis; center has x=0 if length is odd */
for (i = 0, x = (0.5 - FILTER_LENGTH / 2.) * FILTER_STEP;
i < FILTER_LENGTH;
i++, x += FILTER_STEP)
{
if (x == 0)
m_ampl[i] = 1;
else
m_ampl[i] = sin(x) / x;
}
#else
/* Trivial average filter with poor frequency cutoff properties;
* First zero (frequency where amplification=0) = sample rate / filter length
* Cutoff frequency approx <= first zero / 2
*/
for (i = 0, i < FILTER_LENGTH; i++)
m_ampl[i] = 1;
#endif
save_item(NAME(m_level));
save_item(NAME(m_composed_volume));
save_item(NAME(m_composed_sample_index));
save_item(NAME(m_channel_last_sample_time));
save_item(NAME(m_interm_sample_index));
save_item(NAME(m_last_update_time));
save_item(NAME(m_prevx));
save_item(NAME(m_prevy));
machine().save().register_postload(save_prepost_delegate(FUNC(speaker_sound_device::speaker_postload), this));
}
static void recompute_parameters(crtc_ega_t *crtc_ega, int postload)
{
if (crtc_ega->intf != NULL)
{
UINT16 hsync_on_pos, hsync_off_pos, vsync_on_pos, vsync_off_pos;
/* compute the screen sizes */
UINT16 horiz_pix_total = (crtc_ega->horiz_char_total + 5) * crtc_ega->hpixels_per_column;
UINT16 vert_pix_total = crtc_ega->vert_total + 1;
/* determine the visible area, avoid division by 0 */
UINT16 max_visible_x = ( crtc_ega->horiz_disp + 1 ) * crtc_ega->hpixels_per_column - 1;
UINT16 max_visible_y = crtc_ega->vert_disp_end;
/* determine the syncing positions */
int horiz_sync_char_width = ( crtc_ega->horiz_retr_end + 1 ) - ( crtc_ega->horiz_retr_start & 0x1f );
int vert_sync_pix_width = crtc_ega->vert_retr_end - ( crtc_ega->vert_retr_start & 0x0f );
if (horiz_sync_char_width <= 0)
horiz_sync_char_width += 0x10;
if (vert_sync_pix_width <= 0)
vert_sync_pix_width += 0x10;
hsync_on_pos = crtc_ega->horiz_retr_start * crtc_ega->hpixels_per_column;
hsync_off_pos = hsync_on_pos + (horiz_sync_char_width * crtc_ega->hpixels_per_column);
vsync_on_pos = crtc_ega->vert_retr_start; /* + 1 ?? */
vsync_off_pos = vsync_on_pos + vert_sync_pix_width;
/* the Commodore PET computers program a horizontal synch pulse that extends
past the scanline width. I assume that the real device will clamp it */
if (hsync_off_pos > horiz_pix_total)
hsync_off_pos = horiz_pix_total;
if (vsync_off_pos > vert_pix_total)
vsync_off_pos = vert_pix_total;
/* update only if screen parameters changed, unless we are coming here after loading the saved state */
if (postload ||
(horiz_pix_total != crtc_ega->horiz_pix_total) || (vert_pix_total != crtc_ega->vert_pix_total) ||
(max_visible_x != crtc_ega->max_visible_x) || (max_visible_y != crtc_ega->max_visible_y) ||
(hsync_on_pos != crtc_ega->hsync_on_pos) || (vsync_on_pos != crtc_ega->vsync_on_pos) ||
(hsync_off_pos != crtc_ega->hsync_off_pos) || (vsync_off_pos != crtc_ega->vsync_off_pos))
{
/* update the screen if we have valid data */
if ((horiz_pix_total > 0) && (max_visible_x < horiz_pix_total) &&
(vert_pix_total > 0) && (max_visible_y < vert_pix_total) &&
(hsync_on_pos <= horiz_pix_total) && (vsync_on_pos <= vert_pix_total) &&
(hsync_on_pos != hsync_off_pos))
{
rectangle visarea;
attoseconds_t refresh = HZ_TO_ATTOSECONDS(crtc_ega->clock) * (crtc_ega->horiz_char_total + 1) * vert_pix_total;
visarea.min_x = 0;
visarea.min_y = 0;
visarea.max_x = max_visible_x;
visarea.max_y = max_visible_y;
if (LOG) logerror("CRTC_EGA config screen: HTOTAL: 0x%x VTOTAL: 0x%x MAX_X: 0x%x MAX_Y: 0x%x HSYNC: 0x%x-0x%x VSYNC: 0x%x-0x%x Freq: %ffps\n",
horiz_pix_total, vert_pix_total, max_visible_x, max_visible_y, hsync_on_pos, hsync_off_pos - 1, vsync_on_pos, vsync_off_pos - 1, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
crtc_ega->screen->configure(horiz_pix_total, vert_pix_total, visarea, refresh);
crtc_ega->has_valid_parameters = TRUE;
}
else
crtc_ega->has_valid_parameters = FALSE;
crtc_ega->horiz_pix_total = horiz_pix_total;
crtc_ega->vert_pix_total = vert_pix_total;
crtc_ega->max_visible_x = max_visible_x;
crtc_ega->max_visible_y = max_visible_y;
crtc_ega->hsync_on_pos = hsync_on_pos;
crtc_ega->hsync_off_pos = hsync_off_pos;
crtc_ega->vsync_on_pos = vsync_on_pos;
crtc_ega->vsync_off_pos = vsync_off_pos;
update_de_changed_timer(crtc_ega);
update_hsync_changed_timers(crtc_ega);
update_vsync_changed_timers(crtc_ega);
update_vblank_changed_timers(crtc_ega);
}
}
}
static void recompute_parameters(mc6845_t *mc6845, int postload)
{
if (mc6845->intf != NULL)
{
UINT16 hsync_on_pos, hsync_off_pos, vsync_on_pos, vsync_off_pos;
/* compute the screen sizes */
UINT16 horiz_pix_total = (mc6845->horiz_char_total + 1) * mc6845->hpixels_per_column;
UINT16 vert_pix_total = (mc6845->vert_char_total + 1) * (mc6845->max_ras_addr + 1) + mc6845->vert_total_adj;
/* determine the visible area, avoid division by 0 */
UINT16 max_visible_x = mc6845->horiz_disp * mc6845->hpixels_per_column - 1;
UINT16 max_visible_y = mc6845->vert_disp * (mc6845->max_ras_addr + 1) - 1;
/* determine the syncing positions */
UINT8 horiz_sync_char_width = mc6845->sync_width & 0x0f;
UINT8 vert_sync_pix_width = supports_vert_sync_width[mc6845->device_type] ? (mc6845->sync_width >> 4) & 0x0f : 0x10;
if (horiz_sync_char_width == 0)
horiz_sync_char_width = 0x10;
if (vert_sync_pix_width == 0)
vert_sync_pix_width = 0x10;
/* determine the transparent update cycle time, 1 update every 4 character clocks */
mc6845->upd_time = attotime::from_hz(mc6845->clock) * (4 * mc6845->hpixels_per_column);
hsync_on_pos = mc6845->horiz_sync_pos * mc6845->hpixels_per_column;
hsync_off_pos = hsync_on_pos + (horiz_sync_char_width * mc6845->hpixels_per_column);
vsync_on_pos = mc6845->vert_sync_pos * (mc6845->max_ras_addr + 1);
vsync_off_pos = vsync_on_pos + vert_sync_pix_width;
/* the Commodore PET computers program a horizontal synch pulse that extends
past the scanline width. I assume that the real device will clamp it */
if (hsync_off_pos > horiz_pix_total)
hsync_off_pos = horiz_pix_total;
if (vsync_off_pos > vert_pix_total)
vsync_off_pos = vert_pix_total;
/* update only if screen parameters changed, unless we are coming here after loading the saved state */
if (postload ||
(horiz_pix_total != mc6845->horiz_pix_total) || (vert_pix_total != mc6845->vert_pix_total) ||
(max_visible_x != mc6845->max_visible_x) || (max_visible_y != mc6845->max_visible_y) ||
(hsync_on_pos != mc6845->hsync_on_pos) || (vsync_on_pos != mc6845->vsync_on_pos) ||
(hsync_off_pos != mc6845->hsync_off_pos) || (vsync_off_pos != mc6845->vsync_off_pos))
{
/* update the screen if we have valid data */
if ((horiz_pix_total > 0) && (max_visible_x < horiz_pix_total) &&
(vert_pix_total > 0) && (max_visible_y < vert_pix_total) &&
(hsync_on_pos <= horiz_pix_total) && (vsync_on_pos <= vert_pix_total) &&
(hsync_on_pos != hsync_off_pos))
{
rectangle visarea;
attoseconds_t refresh = HZ_TO_ATTOSECONDS(mc6845->clock) * (mc6845->horiz_char_total + 1) * vert_pix_total;
visarea.min_x = 0;
visarea.min_y = 0;
visarea.max_x = max_visible_x;
visarea.max_y = max_visible_y;
if (LOG) logerror("M6845 config screen: HTOTAL: 0x%x VTOTAL: 0x%x MAX_X: 0x%x MAX_Y: 0x%x HSYNC: 0x%x-0x%x VSYNC: 0x%x-0x%x Freq: %ffps\n",
horiz_pix_total, vert_pix_total, max_visible_x, max_visible_y, hsync_on_pos, hsync_off_pos - 1, vsync_on_pos, vsync_off_pos - 1, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
if ( mc6845->screen != NULL )
mc6845->screen->configure(horiz_pix_total, vert_pix_total, visarea, refresh);
mc6845->has_valid_parameters = TRUE;
}
else
mc6845->has_valid_parameters = FALSE;
mc6845->horiz_pix_total = horiz_pix_total;
mc6845->vert_pix_total = vert_pix_total;
mc6845->max_visible_x = max_visible_x;
mc6845->max_visible_y = max_visible_y;
mc6845->hsync_on_pos = hsync_on_pos;
mc6845->hsync_off_pos = hsync_off_pos;
mc6845->vsync_on_pos = vsync_on_pos;
mc6845->vsync_off_pos = vsync_off_pos;
}
}
static DEVICE_START( speaker )
{
speaker_state *sp = get_safe_token(device);
const speaker_interface *intf = (const speaker_interface *) device->static_config();
int i;
double x;
sp->channel = device->machine().sound().stream_alloc(*device, 0, 1, device->machine().sample_rate(), sp, speaker_sound_update);
if (intf != NULL)
{
assert(intf->num_level > 1);
assert(intf->levels != NULL);
sp->num_levels = intf->num_level;
sp->levels = intf->levels;
}
else
{
sp->num_levels = 2;
sp->levels = default_levels;
}
sp->level = 0;
for (i = 0; i < FILTER_LENGTH; i++)
sp->composed_volume[i] = 0;
sp->composed_sample_index = 0;
sp->last_update_time = device->machine().time();
sp->channel_sample_period = HZ_TO_ATTOSECONDS(device->machine().sample_rate());
sp->channel_sample_period_secfrac = ATTOSECONDS_TO_DOUBLE(sp->channel_sample_period);
sp->interm_sample_period = sp->channel_sample_period / RATE_MULTIPLIER;
sp->interm_sample_period_secfrac = ATTOSECONDS_TO_DOUBLE(sp->interm_sample_period);
sp->channel_last_sample_time = sp->channel->sample_time();
sp->channel_next_sample_time = sp->channel_last_sample_time + attotime(0, sp->channel_sample_period);
sp->next_interm_sample_time = sp->channel_last_sample_time + attotime(0, sp->interm_sample_period);
sp->interm_sample_index = 0;
/* Note: To avoid time drift due to floating point inaccuracies,
* it is good if the speaker time synchronizes itself with the stream timing regularly.
*/
/* Compute filter kernel; */
/* (Done for each device though the data is shared...
* No problem really, but should be done as part of system init if I knew how)
*/
#if 1
/* This is an approximated sinc (a perfect sinc makes an ideal low-pass filter).
* FILTER_STEP determines the cutoff frequency,
* which should be below the Nyquist freq, i.e. half the sample rate.
* Smaller step => kernel extends in time domain => lower cutoff freq
* In this case, with sinc, filter step PI corresponds to the Nyq. freq.
* Since we do not get a perfect filter => must lower the cutoff freq some more.
* For example, step PI/(2*RATE_MULTIPLIER) corresponds to cutoff freq = sample rate / 4;
* With -samplerate 48000, cutoff freq is ca 12kHz while the Nyq. freq is 24kHz.
* With -samplerate 96000, cutoff freq is ca 24kHz while the Nyq. freq is 48kHz.
* For a steeper, more efficient filter, increase FILTER_LENGTH at the expense of CPU usage.
*/
#define FILTER_STEP (M_PI / 2 / RATE_MULTIPLIER)
/* Distribute symmetrically on x axis; center has x=0 if length is odd */
for (i = 0, x = (0.5 - FILTER_LENGTH / 2.) * FILTER_STEP;
i < FILTER_LENGTH;
i++, x += FILTER_STEP)
{
if (x == 0)
ampl[i] = 1;
else
ampl[i] = sin(x) / x;
}
#else
/* Trivial average filter with poor frequency cutoff properties;
* First zero (frequency where amplification=0) = sample rate / filter length
* Cutoff frequency approx <= first zero / 2
*/
for (i = 0, i < FILTER_LENGTH; i++)
ampl[i] = 1;
#endif
}
void mc6845_device::recompute_parameters(bool postload)
{
UINT16 hsync_on_pos, hsync_off_pos, vsync_on_pos, vsync_off_pos;
UINT16 video_char_height = m_max_ras_addr + 1; // fix garbage at the bottom of the screen (eg victor9k)
// Would be useful for 'interlace and video' mode support...
// UINT16 frame_char_height = (MODE_INTERLACE_AND_VIDEO ? m_max_ras_addr / 2 : m_max_ras_addr) + 1;
/* compute the screen sizes */
UINT16 horiz_pix_total = (m_horiz_char_total + 1) * m_hpixels_per_column;
UINT16 vert_pix_total = (m_vert_char_total + 1) * video_char_height + m_vert_total_adj;
/* determine the visible area, avoid division by 0 */
UINT16 max_visible_x = m_horiz_disp * m_hpixels_per_column - 1;
UINT16 max_visible_y = m_vert_disp * video_char_height - 1;
/* determine the syncing positions */
UINT8 horiz_sync_char_width = m_sync_width & 0x0f;
UINT8 vert_sync_pix_width = m_supports_vert_sync_width ? (m_sync_width >> 4) & 0x0f : 0x10;
if (horiz_sync_char_width == 0)
horiz_sync_char_width = 0x10;
if (vert_sync_pix_width == 0)
vert_sync_pix_width = 0x10;
/* determine the transparent update cycle time, 1 update every 4 character clocks */
m_upd_time = attotime::from_hz(m_clock) * (4 * m_hpixels_per_column);
hsync_on_pos = m_horiz_sync_pos * m_hpixels_per_column;
hsync_off_pos = hsync_on_pos + (horiz_sync_char_width * m_hpixels_per_column);
vsync_on_pos = m_vert_sync_pos * video_char_height;
vsync_off_pos = vsync_on_pos + vert_sync_pix_width;
// the Commodore PET computers have a non-standard 20kHz monitor which
// requires a wider HSYNC pulse that extends past the scanline width
if (hsync_off_pos > horiz_pix_total)
hsync_off_pos = horiz_pix_total;
if (vsync_on_pos > vert_pix_total)
vsync_on_pos = vert_pix_total;
if (vsync_off_pos > vert_pix_total)
vsync_off_pos = vert_pix_total;
/* update only if screen parameters changed, unless we are coming here after loading the saved state */
if (postload ||
(horiz_pix_total != m_horiz_pix_total) || (vert_pix_total != m_vert_pix_total) ||
(max_visible_x != m_max_visible_x) || (max_visible_y != m_max_visible_y) ||
(hsync_on_pos != m_hsync_on_pos) || (vsync_on_pos != m_vsync_on_pos) ||
(hsync_off_pos != m_hsync_off_pos) || (vsync_off_pos != m_vsync_off_pos))
{
/* update the screen if we have valid data */
if ((horiz_pix_total > 0) && (max_visible_x < horiz_pix_total) &&
(vert_pix_total > 0) && (max_visible_y < vert_pix_total) &&
(hsync_on_pos <= horiz_pix_total) && (vsync_on_pos <= vert_pix_total) &&
(hsync_on_pos != hsync_off_pos))
{
rectangle visarea;
attoseconds_t refresh = HZ_TO_ATTOSECONDS(m_clock) * (m_horiz_char_total + 1) * vert_pix_total;
// This doubles the vertical resolution, required for 'interlace and video' mode support.
// Tested and works for super80v, which was designed with this in mind (choose green or monochrome colour in config switches).
// However it breaks some other drivers (apricot,a6809,victor9k,bbc(mode7)).
// So, it is commented out for now.
// Also, the mode-register change needs to be added to the changed-parameter tests above.
if (MODE_INTERLACE_AND_VIDEO)
{
//max_visible_y *= 2;
//vert_pix_total *= 2;
}
if(m_show_border_area)
visarea.set(0, horiz_pix_total-1, 0, vert_pix_total-1);
else
visarea.set(0 + m_visarea_adjust_min_x, max_visible_x + m_visarea_adjust_max_x, 0 + m_visarea_adjust_min_y, max_visible_y + m_visarea_adjust_max_y);
if (LOG) logerror("M6845 config screen: HTOTAL: 0x%x VTOTAL: 0x%x MAX_X: 0x%x MAX_Y: 0x%x HSYNC: 0x%x-0x%x VSYNC: 0x%x-0x%x Freq: %ffps\n",
horiz_pix_total, vert_pix_total, max_visible_x, max_visible_y, hsync_on_pos, hsync_off_pos - 1, vsync_on_pos, vsync_off_pos - 1, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
if ( m_screen != NULL )
m_screen->configure(horiz_pix_total, vert_pix_total, visarea, refresh);
if(!m_reconfigure_cb.isnull())
m_reconfigure_cb(horiz_pix_total, vert_pix_total, visarea, refresh);
m_has_valid_parameters = true;
}
else
m_has_valid_parameters = false;
m_horiz_pix_total = horiz_pix_total;
m_vert_pix_total = vert_pix_total;
m_max_visible_x = max_visible_x;
m_max_visible_y = max_visible_y;
m_hsync_on_pos = hsync_on_pos;
m_hsync_off_pos = hsync_off_pos;
m_vsync_on_pos = vsync_on_pos;
m_vsync_off_pos = vsync_off_pos;
m_line_counter = 0;
}
}
