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enigma2: better star blink rate
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@happppp
happppp committed Dec 4, 2024
1 parent 706502c commit 521ff6d
Showing 1 changed file with 31 additions and 30 deletions.
61 changes: 31 additions & 30 deletions src/mame/misc/enigma2.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,6 @@ enigma2b (1981)
Conversion like enigma2a, but boots with 1981 copyright and Phantoms II title
TODO:
- enigma2 - Star blinking frequency
- enigma2b - bad sound ROM?
Expand Down Expand Up @@ -202,7 +201,7 @@ class enigma2_state : public driver_device
optional_region_ptr<uint8_t> m_stars;
required_shared_ptr<uint8_t> m_videoram;

int m_blink_count = 0;
uint8_t m_blink_count = 0;
uint8_t m_sound_latch = 0;
uint8_t m_last_sound_data = 0;
uint8_t m_protection_data = 0;
Expand Down Expand Up @@ -263,13 +262,13 @@ TIMER_CALLBACK_MEMBER(enigma2_state::interrupt_assert_callback)
uint16_t next_counter;
int next_vpos;

/* compute vector and set the interrupt line */
// compute vector and set the interrupt line
int vpos = m_screen->vpos();
uint16_t counter = vpos_to_vysnc_chain_counter(vpos);
uint8_t vector = 0xc7 | ((counter & 0x80) >> 3) | ((~counter & 0x80) >> 4);
m_maincpu->set_input_line_and_vector(0, ASSERT_LINE, vector); // Z80

/* set up for next interrupt */
// set up for next interrupt
if (counter == INT_TRIGGER_COUNT_1)
next_counter = INT_TRIGGER_COUNT_2;
else
Expand Down Expand Up @@ -353,17 +352,20 @@ uint32_t enigma2_state::screen_update_enigma2(screen_device &screen, bitmap_rgb3
uint8_t bit;
uint8_t color;

/* read the video RAM */
// read the video RAM
if ((x & 0x07) == 0x00)
{
offs_t color_map_address = (y >> 3 << 5) | (x >> 3);

/* the schematics shows it like this, but it doesn't work as this would
produce no stars, due to the contents of the PROM -- maybe there is
a star disabled bit somewhere that's connected here instead of flip_screen() */
/* star_map_address = (y >> 4 << 6) | (enigma2_flip_screen_get() << 5) | (x >> 3); */
//offs_t star_map_address = (y >> 4 << 6) | (m_flip_screen ? 0x20 : 0) | (x >> 3);
offs_t star_map_address = (y >> 4 << 6) | 0x20 | (x >> 3);
if (m_blink_count & 0x08)

// blink rate is with an RC osc, this is an estimation based on PCB video
// (yes, the intervals are uneven like this)
if (m_blink_count & 0x30)
star_map_address |= 0x400;

offs_t videoram_address = (y << 5) | (x >> 3);
Expand All @@ -382,7 +384,7 @@ uint32_t enigma2_state::screen_update_enigma2(screen_device &screen, bitmap_rgb3
star_color = m_stars[star_map_address] & 0x07;
}

/* plot the current pixel */
// plot the current pixel
if (m_flip_screen)
{
bit = video_data & 0x80;
Expand All @@ -398,30 +400,28 @@ uint32_t enigma2_state::screen_update_enigma2(screen_device &screen, bitmap_rgb3
color = fore_color;
else
{
/* stars only appear at certain positions */
// stars only appear at certain positions
color = ((x & y & 0x0f) == 0x0f) ? star_color : 0;
}

bitmap.pix(bitmap_y, x) = m_palette->pen_color(color);

/* next pixel */
// next pixel
x = x + 1;

/* end of line? */
// end of line?
if (x == 0)
{
/* end of screen? */
// end of screen?
if (bitmap_y == visarea.max_y)
break;

/* next row */
// next row
y = y + 1;
bitmap_y = bitmap_y + 1;
}
}

m_blink_count++;

return 0;
}

Expand All @@ -439,19 +439,19 @@ uint32_t enigma2_state::screen_update_enigma2a(screen_device &screen, bitmap_rgb
uint8_t bit;
pen_t pen;

/* read the video RAM */
// read the video RAM
if ((x & 0x07) == 0x00)
{
offs_t videoram_address = (y << 5) | (x >> 3);

/* when the screen is flipped, all the video address bits are inverted,
and the adder at 16A is activated */
if (m_flip_screen) videoram_address = (~videoram_address + 0x0400) & 0x1fff;
if (m_flip_screen) videoram_address = (~videoram_address + 0x0400) & 0x1fff;

video_data = m_videoram[videoram_address];
}

/* plot the current pixel */
// plot the current pixel
if (m_flip_screen)
{
bit = video_data & 0x80;
Expand All @@ -466,17 +466,17 @@ uint32_t enigma2_state::screen_update_enigma2a(screen_device &screen, bitmap_rgb
pen = bit ? rgb_t::white() : rgb_t::black();
bitmap.pix(bitmap_y, x) = pen;

/* next pixel */
// next pixel
x = x + 1;

/* end of line? */
// end of line?
if (x == 0)
{
/* end of screen? */
// end of screen?
if (bitmap_y == visarea.max_y)
break;

/* next row */
// next row
y = y + 1;
bitmap_y = bitmap_y + 1;
}
Expand Down Expand Up @@ -518,7 +518,7 @@ uint8_t enigma2_state::dip_switch_r(offs_t offset)

void enigma2_state::sound_data_w(uint8_t data)
{
/* clock sound latch shift register on rising edge of D2 */
// clock sound latch shift register on rising edge of D2
if (!(data & 0x04) && (m_last_sound_data & 0x04))
m_sound_latch = (m_sound_latch >> 1) | (~data << 7 & 0x80);

Expand Down Expand Up @@ -724,7 +724,7 @@ INPUT_PORTS_END

void enigma2_state::enigma2(machine_config &config)
{
/* basic machine hardware */
// basic machine hardware
Z80(config, m_maincpu, CPU_CLOCK);
m_maincpu->set_addrmap(AS_PROGRAM, &enigma2_state::enigma2_main_cpu_map);

Expand All @@ -733,14 +733,15 @@ void enigma2_state::enigma2(machine_config &config)

config.set_maximum_quantum(attotime::from_hz(m_audiocpu->clock() / 4));

/* video hardware */
// video hardware
SCREEN(config, m_screen, SCREEN_TYPE_RASTER);
m_screen->set_raw(PIXEL_CLOCK, HTOTAL, HBEND, HBSTART, VTOTAL, VBEND, VBSTART);
m_screen->set_screen_update(FUNC(enigma2_state::screen_update_enigma2));
m_screen->screen_vblank().set([this] (int state) { if (state) m_blink_count++; });

PALETTE(config, m_palette, palette_device::GBR_3BIT);

/* audio hardware */
// audio hardware
SPEAKER(config, "mono").front_center();

ay8910_device &aysnd(AY8910(config, "aysnd", AY8910_CLOCK));
Expand All @@ -752,7 +753,7 @@ void enigma2_state::enigma2(machine_config &config)

void enigma2_state::enigma2a(machine_config &config)
{
/* basic machine hardware */
// basic machine hardware
I8080(config, m_maincpu, CPU_CLOCK);
m_maincpu->set_addrmap(AS_PROGRAM, &enigma2_state::enigma2a_main_cpu_map);
m_maincpu->set_addrmap(AS_IO, &enigma2_state::enigma2a_main_cpu_io_map);
Expand All @@ -762,12 +763,12 @@ void enigma2_state::enigma2a(machine_config &config)

config.set_maximum_quantum(attotime::from_hz(m_audiocpu->clock() / 4));

/* video hardware */
// video hardware
SCREEN(config, m_screen, SCREEN_TYPE_RASTER);
m_screen->set_raw(PIXEL_CLOCK, HTOTAL, HBEND, HBSTART, VTOTAL, VBEND, VBSTART);
m_screen->set_screen_update(FUNC(enigma2_state::screen_update_enigma2a));

/* audio hardware */
// audio hardware
SPEAKER(config, "mono").front_center();

ay8910_device &aysnd(AY8910(config, "aysnd", AY8910_CLOCK));
Expand Down Expand Up @@ -820,7 +821,7 @@ ROM_START( enigma2b )
ROM_LOAD( "ic32.bin", 0x4000, 0x0800, CRC(098ac15b) SHA1(cce28a2540a9eabb473391fff92895129ae41751) )
ROM_LOAD( "ic42.bin", 0x4800, 0x0800, CRC(240a9d4b) SHA1(ca1c69fafec0471141ce1254ddfaef54fecfcbf0) )

/* this rom was completely broken on this pcb.. */
// this rom was completely broken on this pcb..
ROM_REGION( 0x10000, "audiocpu", 0 )
ROM_LOAD( "sound.bin", 0x0000, 0x0800, BAD_DUMP CRC(5f092d3c) SHA1(17c70f6af1b5560a45e6b1bdb330a98b27570fe9) )
ROM_END
Expand Down

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