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sega/megadriv.cpp: replace irq_callback with vpa_after / vpa_sync cpu_space_map #14038

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sega/megadriv.cpp: replace irq_callback with vpa_after / vpa_sync cpu_space_map #14038

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75a82e0
sega/megadriv.cpp: replace irq_callback with vpa_after / vpa_sync cpu…
angelosa Aug 10, 2025
c7d84fa
video/315_5313.h: unify VDP acknowledge signal
angelosa Aug 11, 2025
6e08fd8
sega/segac2.cpp: convert to cpu_space_map
angelosa Aug 12, 2025
ea92a81
hash/megadriv.xml: update QA
angelosa Aug 12, 2025
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19 changes: 5 additions & 14 deletions hash/megadriv.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -3055,14 +3055,11 @@ No [VDP] sprites


<!-- This was marked as rev. A on the EA sticker, but its header (and ROM markings) uses the Jpn title... weird situation :-) -->
<software name="fatalrewa" cloneof="fatalrew" supported="no">
<software name="fatalrewa" cloneof="fatalrew" supported="yes">
<!-- Originally marked as Fatal Rewind, boots as The Killing Game Show -->
<description>The Killing Game Show (Europe)</description>
<year>1991</year>
<publisher>Electronic Arts</publisher>
<notes><![CDATA[
Crashes after EA logo, requires better [VDP] irq handling
]]></notes>
<part name="cart" interface="megadriv_cart">
<feature name="pcb" value="PWB SC40X1 REV B"/>
<feature name="u1" value="KILLING GAME SHOW KIL03"/> <!-- location not really marked on PCB, using u1 for consistency -->
Expand All @@ -3074,13 +3071,10 @@ Crashes after EA logo, requires better [VDP] irq handling


<!-- Only Euro is confirmed -->
<software name="fatalrew" supported="no">
<software name="fatalrew" supported="yes">
<description>Fatal Rewind (Europe, USA, rev. A)</description>
<year>1991</year>
<publisher>Electronic Arts</publisher>
<notes><![CDATA[
Crashes after EA logo, requires better [VDP] irq handling
]]></notes>
<part name="cart" interface="megadriv_cart">
<feature name="pcb" value="PWB SC40X1 REV B"/>
<feature name="u1" value="FATAL REWIND FAT04"/> <!-- location not really marked on PCB, using u1 for consistency -->
Expand Down Expand Up @@ -17742,12 +17736,12 @@ https://segaretro.org/Elitserien_96
</part>
</software>

<software name="killshow" cloneof="fatalrew" supported="no">
<software name="killshow" cloneof="fatalrew" supported="partial">
<description>The Killing Game Show (Japan)</description>
<year>1993</year>
<publisher>Electronic Arts Victor</publisher>
<notes><![CDATA[
Crashes after EA logo, requires better [VDP] irq handling
No sound in intro opening (verify)
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Can't find a reference for this specific version, may be related to MT09222 anyway.

]]></notes>
<info name="serial" value="EM20021"/>
<info name="release" value="19930820"/>
Expand Down Expand Up @@ -27237,13 +27231,10 @@ Throws "this game is [...] european megadrive system" even with megadriv system
</part>
</software>

<software name="sesame" supported="no">
<software name="sesame" supported="yes">
<description>Sesame Street Counting Cafe (USA)</description>
<year>1994</year>
<publisher>Electronic Arts</publisher>
<notes><![CDATA[
Black screen, requires better [VDP] irq handling
]]></notes>
<part name="cart" interface="megadriv_cart">
<dataarea name="rom" width="16" endianness="big" size="1048576">
<rom name="sesame street counting cafe (usa).bin" size="1048576" crc="0a4f48c3" sha1="d5ef2b50cf1a22e07401f6a14c7946df66d8b605"/>
Expand Down
46 changes: 26 additions & 20 deletions src/devices/video/315_5313.cpp
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Expand Up @@ -585,30 +585,37 @@ void sega315_5313_device::vdp_set_register(int regnum, u8 value)
{
//osd_printf_debug("setting reg 0, irq enable is now %d\n", MEGADRIVE_REG0_IRQ4_ENABLE);

// fatalrew and sesame are very fussy about pending interrupts.
// Former in particular will quickly enable both after the EA logo (cfr. killshow at PC=0x2267a),
// and irq 6 will jump to illegal addresses because the correlated routine isn't set in stack
// but delayed a bit.
// Note that irq 6 is masked for about 5 frames, leaving the assumption that it mustn't
// be left on during all this time.
if (m_irq4_pending)
// fatalrew/killshow and sesame are very fussy about pending interrupts.
// https://jsgroth.dev/blog/posts/emulator-bugs-fatal-rewind/
// https://gendev.spritesmind.net/forum/viewtopic.php?t=2202
// this gets 1 cycle delay on both HINT and VINT for gen_test_int_delay.bin
// TODO: first time around said test prints HINT=20, pressing start gives the correct value
if (m_irq4_pending && MEGADRIVE_REG0_IRQ4_ENABLE)
{
if (MEGADRIVE_REG0_IRQ4_ENABLE)
m_lv4irqline_callback(true);
else
m_lv4irqline_callback(false);
m_irq4_on_timer->adjust(attotime::from_ticks(16, clock() / 4));
// if (MEGADRIVE_REG0_IRQ4_ENABLE)
// m_lv4irqline_callback(true);
// else
// m_lv4irqline_callback(false);
}
else
m_lv4irqline_callback(false);

}

if (regnum == 0x01)
{
if (m_irq6_pending)
if (m_irq6_pending && MEGADRIVE_REG01_IRQ6_ENABLE)
{
if (MEGADRIVE_REG01_IRQ6_ENABLE)
m_lv6irqline_callback(true);
else
m_lv6irqline_callback(false);
m_irq6_on_timer->adjust(attotime::from_ticks(16, clock() / 4));

// if (MEGADRIVE_REG01_IRQ6_ENABLE)
// m_lv6irqline_callback(true);
// else
// m_lv6irqline_callback(false);
}
else
m_lv6irqline_callback(false);
}

// if (regnum == 0x0a)
Expand Down Expand Up @@ -2254,7 +2261,7 @@ void sega315_5313_device::vdp_handle_scanline_callback(int scanline)
if (get_scanline_counter() == m_irq6_scanline)
{
// osd_printf_debug("x %d", get_scanline_counter());
m_irq6_on_timer->adjust(attotime::from_usec(6));
m_irq6_on_timer->adjust(attotime::from_ticks(16, clock() / 4));
m_irq6_pending = 1;
m_vblank_flag = 1;

Expand All @@ -2276,8 +2283,7 @@ void sega315_5313_device::vdp_handle_scanline_callback(int scanline)

if (MEGADRIVE_REG0_IRQ4_ENABLE)
{
// TODO: arbitrary timing
m_irq4_on_timer->adjust(attotime::from_usec(1));
m_irq4_on_timer->adjust(attotime::from_ticks(16, clock() / 4));
//osd_printf_debug("irq4 on scanline %d reload %d\n", get_scanline_counter(), MEGADRIVE_REG0A_HINT_VALUE);
}
else
Expand Down Expand Up @@ -2320,7 +2326,7 @@ void sega315_5313_device::vdp_handle_eof()

m_vblank_flag = 0;
// Not here, breaks warlock
//m_irq6_pending = 0;
// m_irq6_pending = 0;

/* Set it to -1 here, so it becomes 0 when the first timer kicks in */
if (!m_use_alt_timing) m_scanline_counter = -1;
Expand Down
19 changes: 15 additions & 4 deletions src/devices/video/315_5313.h
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Original file line number Diff line number Diff line change
Expand Up @@ -29,8 +29,8 @@ class sega315_5313_device : public sega315_5313_mode4_device, public device_gfx_
typedef device_delegate<void (int scanline)> md_32x_scanline_helper_delegate;

auto snd_irq() { return m_sndirqline_callback.bind(); }
auto lv6_irq() { return m_lv6irqline_callback.bind(); }
auto lv4_irq() { return m_lv4irqline_callback.bind(); }
auto vint_cb() { return m_lv6irqline_callback.bind(); }
auto hint_cb() { return m_lv4irqline_callback.bind(); }

void set_lcm_scaling(bool lcm_scaling) { m_lcm_scaling = lcm_scaling; }
void set_alt_timing(int use_alt_timing) { m_use_alt_timing = use_alt_timing; }
Expand Down Expand Up @@ -73,8 +73,19 @@ class sega315_5313_device : public sega315_5313_mode4_device, public device_gfx_
TIMER_CALLBACK_MEMBER(irq4_on_timer_callback);
void vdp_handle_eof();
void device_reset_old();
void vdp_clear_irq6_pending() { m_irq6_pending = 0; }
void vdp_clear_irq4_pending() { m_irq4_pending = 0; }
void irq_ack()
{
if (m_irq6_pending)
{
m_irq6_pending = 0;
m_lv6irqline_callback(false);
}
else if (m_irq4_pending)
{
m_irq4_pending = 0;
m_lv4irqline_callback(false);
}
}

// set some VDP variables at start (shall be moved to a device interface?)
void set_scanline_counter(int scanline) { m_scanline_counter = scanline; }
Expand Down
61 changes: 28 additions & 33 deletions src/mame/sega/calcune.cpp
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Expand Up @@ -52,10 +52,10 @@ class calcune_state : public driver_device
int m_vdp_state = 0;

void vdp_sndirqline_callback_genesis_z80(int state);
void vdp_lv6irqline_callback_genesis_68k(int state);
void vdp_lv4irqline_callback_genesis_68k(int state);
void vdp_vint_cb(int state);
void vdp_hint_cb(int state);

IRQ_CALLBACK_MEMBER(genesis_int_callback);
void cpu_space_map(address_map &map);

uint16_t cal_700000_r();
void cal_770000_w(uint16_t data);
Expand Down Expand Up @@ -206,42 +206,37 @@ void calcune_state::machine_reset()
m_vdp[1]->device_reset_old();
}


IRQ_CALLBACK_MEMBER(calcune_state::genesis_int_callback)
void calcune_state::cpu_space_map(address_map &map)
{
if (irqline==4)
{
m_vdp[0]->vdp_clear_irq4_pending();
}

if (irqline==6)
{
m_vdp[0]->vdp_clear_irq6_pending();
}

return (0x60+irqline*4)/4; // vector address
map(0xfffff3, 0xfffff3).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 25; }));
// IPL0, should be unused by Calcune
map(0xfffff5, 0xfffff5).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 26; }));
map(0xfffff7, 0xfffff7).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 27; }));
map(0xfffff9, 0xfffff9).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([this] () -> u8 {
m_vdp[0]->irq_ack();
return 28;
}));
map(0xfffffb, 0xfffffb).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 29; }));
map(0xfffffd, 0xfffffd).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([this] () -> u8 {
m_vdp[0]->irq_ack();
return 30;
}));
map(0xffffff, 0xffffff).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 31; }));
}

void calcune_state::vdp_sndirqline_callback_genesis_z80(int state)
{
}

void calcune_state::vdp_lv6irqline_callback_genesis_68k(int state)
// this looks odd but is the logic the Genesis code requires
void calcune_state::vdp_vint_cb(int state)
{
// this looks odd but is the logic the Genesis code requires
if (state == ASSERT_LINE)
m_maincpu->set_input_line(6, HOLD_LINE);
else
m_maincpu->set_input_line(6, CLEAR_LINE);
m_maincpu->set_input_line(6, state ? ASSERT_LINE : CLEAR_LINE);
}

void calcune_state::vdp_lv4irqline_callback_genesis_68k(int state)
void calcune_state::vdp_hint_cb(int state)
{
// this looks odd but is the logic the Genesis code requires
if (state == ASSERT_LINE)
m_maincpu->set_input_line(4, HOLD_LINE);
else
m_maincpu->set_input_line(4, CLEAR_LINE);
m_maincpu->set_input_line(4, state ? ASSERT_LINE : CLEAR_LINE);
}

void calcune_state::machine_start()
Expand All @@ -256,7 +251,7 @@ void calcune_state::calcune(machine_config &config)
{
M68000(config, m_maincpu, OSC1_CLOCK / 7); /* 7.67 MHz */
m_maincpu->set_addrmap(AS_PROGRAM, &calcune_state::calcune_map);
m_maincpu->set_irq_acknowledge_callback(FUNC(calcune_state::genesis_int_callback));
m_maincpu->set_addrmap(m68000_base_device::AS_CPU_SPACE, &calcune_state::cpu_space_map);

Z80(config, "z80", OSC1_CLOCK / 15).set_disable(); /* 3.58 MHz, no code is ever uploaded for the Z80, so it's unused here even if it is present on the PCB */

Expand All @@ -271,8 +266,8 @@ void calcune_state::calcune(machine_config &config)
SEGA315_5313(config, m_vdp[0], OSC1_CLOCK, m_maincpu);
m_vdp[0]->set_is_pal(false);
m_vdp[0]->snd_irq().set(FUNC(calcune_state::vdp_sndirqline_callback_genesis_z80));
m_vdp[0]->lv6_irq().set(FUNC(calcune_state::vdp_lv6irqline_callback_genesis_68k));
m_vdp[0]->lv4_irq().set(FUNC(calcune_state::vdp_lv4irqline_callback_genesis_68k));
m_vdp[0]->vint_cb().set(FUNC(calcune_state::vdp_vint_cb));
m_vdp[0]->hint_cb().set(FUNC(calcune_state::vdp_hint_cb));
m_vdp[0]->set_alt_timing(1);
m_vdp[0]->add_route(ALL_OUTPUTS, "speaker", 0.25, 0);
m_vdp[0]->add_route(ALL_OUTPUTS, "speaker", 0.25, 1);
Expand All @@ -281,8 +276,8 @@ void calcune_state::calcune(machine_config &config)
m_vdp[1]->set_is_pal(false);
// are these not hooked up or should they OR with the other lines?
// m_vdp[1]->snd_irq().set(FUNC(calcune_state::vdp_sndirqline_callback_genesis_z80));
// m_vdp[1]->lv6_irq().set(FUNC(calcune_state::vdp_lv6irqline_callback_genesis_68k));
// m_vdp[1]->lv4_irq().set(FUNC(calcune_state::vdp_lv4irqline_callback_genesis_68k));
// m_vdp[1]->vint_cb().set(FUNC(calcune_state::vdp_vint_cb));
// m_vdp[1]->hint_cb().set(FUNC(calcune_state::vdp_hint_cb));
m_vdp[1]->set_alt_timing(1);
m_vdp[1]->add_route(ALL_OUTPUTS, "speaker", 0.25, 0);
m_vdp[1]->add_route(ALL_OUTPUTS, "speaker", 0.25, 1);
Expand Down
59 changes: 27 additions & 32 deletions src/mame/sega/megadriv.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -736,41 +736,36 @@ void md_base_state::vdp_sndirqline_callback_genesis_z80(int state)
}
}

// this comes from the vdp, and is connected to 68k irq level 6 (main vbl interrupt)
void md_core_state::vdp_lv6irqline_callback_genesis_68k(int state)
// this comes from the vdp, and is connected to 68k irq level 6 (IPL2, main vbl interrupt)
void md_core_state::vdp_vint_cb(int state)
{
if (state == ASSERT_LINE)
m_maincpu->set_input_line(6, HOLD_LINE);
else
m_maincpu->set_input_line(6, CLEAR_LINE);
m_maincpu->set_input_line(6, state ? ASSERT_LINE : CLEAR_LINE);
}

// this comes from the vdp, and is connected to 68k irq level 4 (raster interrupt)
void md_core_state::vdp_lv4irqline_callback_genesis_68k(int state)
// this comes from the vdp, and is connected to 68k irq level 4 (IPL1, raster interrupt)
void md_core_state::vdp_hint_cb(int state)
{
if (state == ASSERT_LINE)
m_maincpu->set_input_line(4, HOLD_LINE);
else
m_maincpu->set_input_line(4, CLEAR_LINE);
m_maincpu->set_input_line(4, state ? ASSERT_LINE : CLEAR_LINE);
}

/* Callback when the 68k takes an IRQ */
IRQ_CALLBACK_MEMBER(md_core_state::genesis_int_callback)
void md_core_state::cpu_space_map(address_map &map)
{
if (irqline==4)
{
m_vdp->vdp_clear_irq4_pending();
}

if (irqline==6)
{
m_vdp->vdp_clear_irq6_pending();
}

return (0x60+irqline*4)/4; // vector address
map(0xfffff3, 0xfffff3).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 25; }));
// TODO: IPL0 (external irq tied to VDP IE2)
map(0xfffff5, 0xfffff5).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 26; }));
map(0xfffff7, 0xfffff7).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 27; }));
map(0xfffff9, 0xfffff9).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([this] () -> u8 {
m_vdp->irq_ack();
return 28;
}));
map(0xfffffb, 0xfffffb).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 29; }));
map(0xfffffd, 0xfffffd).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([this] () -> u8 {
m_vdp->irq_ack();
return 30;
}));
map(0xffffff, 0xffffff).before_time(m_maincpu, FUNC(m68000_device::vpa_sync)).after_delay(m_maincpu, FUNC(m68000_device::vpa_after)).lr8(NAME([] () -> u8 { return 31; }));
}


void md_core_state::megadriv_timers(machine_config &config)
{
TIMER(config, m_scan_timer).configure_generic(m_vdp, FUNC(sega315_5313_device::megadriv_scanline_timer_callback));
Expand All @@ -779,15 +774,15 @@ void md_core_state::megadriv_timers(machine_config &config)
void md_core_state::md_core_ntsc(machine_config &config)
{
M68000(config, m_maincpu, MASTER_CLOCK_NTSC / 7); // 7.67 MHz
m_maincpu->set_irq_acknowledge_callback(FUNC(md_core_state::genesis_int_callback));
m_maincpu->set_addrmap(m68000_base_device::AS_CPU_SPACE, &md_core_state::cpu_space_map);
// IRQs are handled via the timers

megadriv_timers(config);

SEGA315_5313(config, m_vdp, MASTER_CLOCK_NTSC, m_maincpu);
m_vdp->set_is_pal(false);
m_vdp->lv6_irq().set(FUNC(md_core_state::vdp_lv6irqline_callback_genesis_68k));
m_vdp->lv4_irq().set(FUNC(md_core_state::vdp_lv4irqline_callback_genesis_68k));
m_vdp->vint_cb().set(FUNC(md_core_state::vdp_vint_cb));
m_vdp->hint_cb().set(FUNC(md_core_state::vdp_hint_cb));
m_vdp->set_screen("megadriv");

SCREEN(config, m_screen, SCREEN_TYPE_RASTER);
Expand All @@ -803,15 +798,15 @@ void md_core_state::md_core_ntsc(machine_config &config)
void md_core_state::md_core_pal(machine_config &config)
{
M68000(config, m_maincpu, MASTER_CLOCK_PAL / 7); // 7.67 MHz
m_maincpu->set_irq_acknowledge_callback(FUNC(md_core_state::genesis_int_callback));
m_maincpu->set_addrmap(m68000_base_device::AS_CPU_SPACE, &md_core_state::cpu_space_map);
// IRQs are handled via the timers

megadriv_timers(config);

SEGA315_5313(config, m_vdp, MASTER_CLOCK_PAL, m_maincpu);
m_vdp->set_is_pal(true);
m_vdp->lv6_irq().set(FUNC(md_core_state::vdp_lv6irqline_callback_genesis_68k));
m_vdp->lv4_irq().set(FUNC(md_core_state::vdp_lv4irqline_callback_genesis_68k));
m_vdp->vint_cb().set(FUNC(md_core_state::vdp_vint_cb));
m_vdp->hint_cb().set(FUNC(md_core_state::vdp_hint_cb));
m_vdp->set_screen("megadriv");

SCREEN(config, m_screen, SCREEN_TYPE_RASTER);
Expand Down
7 changes: 4 additions & 3 deletions src/mame/sega/megadriv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -54,10 +54,11 @@ class md_core_state : public driver_device
optional_ioport m_io_reset;

private:
IRQ_CALLBACK_MEMBER(genesis_int_callback);
// IRQ_CALLBACK_MEMBER(genesis_int_callback);
void cpu_space_map(address_map &map);

void vdp_lv6irqline_callback_genesis_68k(int state);
void vdp_lv4irqline_callback_genesis_68k(int state);
void vdp_vint_cb(int state);
void vdp_hint_cb(int state);

void megadriv_timers(machine_config &config);
};
Expand Down
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