bus/nes: Improved support for BMC-64IN1NR boards. (#9586)

New working software list additions (nes.xml)
-----------------------------------
76 in 1 Y2K [superretrogamer2741]
Super HiK 42 in 1 (K-42001) [Consolethinks]

hash/nes.xml

@@ -84139,6 +84139,21 @@ be better to redump them properly. -->
 		</part>
 	</software>
 
+	<software name="mc_76y2k">
+		<description>76 in 1 Y2K</description>
+		<year>19??</year>
+		<publisher>&lt;pirate&gt;</publisher>
+		<part name="cart" interface="nes_cart">
+			<feature name="slot" value="bmc_64y2k" />
+			<dataarea name="prg" size="2097152">
+				<rom name="y2k 76-in-1.prg" size="2097152" crc="736dd9e1" sha1="d666c646342fd5c72630d989d3f633c53143ef33" />
+			</dataarea>
+			<!-- 8k VRAM on cartridge -->
+			<dataarea name="vram" size="8192">
+			</dataarea>
+		</part>
+	</software>
+
 	<software name="mc_77">
 		<description>77 in 1 (NT141)</description>
 		<year>19??</year>
@@ -85882,6 +85897,21 @@ be better to redump them properly. -->
 		</part>
 	</software>
 
+	<software name="mc_sh42">
+		<description>Super HiK 42 in 1 (K-42001)</description>
+		<year>1998</year>
+		<publisher>&lt;pirate&gt;</publisher>
+		<part name="cart" interface="nes_cart">
+			<feature name="slot" value="bmc_64y2k" />
+			<dataarea name="prg" size="1048576">
+				<rom name="super hik 42-in-1 (k-42001).prg" size="1048576" crc="ad97266b" sha1="a10bd03f1e125fa1d39b1c9db2b49b783de3dd45" />
+			</dataarea>
+			<!-- 8k VRAM on cartridge -->
+			<dataarea name="vram" size="8192">
+			</dataarea>
+		</part>
+	</software>
+
 	<software name="mc_sh6ek">
 		<description>1994 Super HIK 6 in 1 (EK-601)</description>
 		<year>19??</year>

src/devices/bus/nes/multigame.cpp

@@ -357,8 +357,8 @@ nes_bmc_22games_device::nes_bmc_22games_device(const machine_config &mconfig, co
 {
 }
 
-nes_bmc_64y2k_device::nes_bmc_64y2k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+nes_bmc_64y2k_device::nes_bmc_64y2k_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
-	: nes_nrom_device(mconfig, NES_BMC_64Y2K, tag, owner, clock)
+	: nes_nrom_device(mconfig, NES_BMC_64Y2K, tag, owner, clock), m_reg_mask(0)
 {
 }
 
@@ -986,14 +986,11 @@ void nes_bmc_64y2k_device::device_start()
 
 void nes_bmc_64y2k_device::pcb_reset()
 {
-	m_chr_source = m_vrom_chunks ? CHRROM : CHRRAM;
+	m_reg_mask = m_chr_source == CHRROM ? 0x03 : 0x01;
-	chr8(0, m_chr_source);
-
 	m_reg[0] = 0x80;
 	m_reg[1] = 0x43;
 	m_reg[2] = m_reg[3] = 0;
-	set_prg();
+	update_banks();
-	set_nt_mirroring(PPU_MIRROR_VERT);
 }
 
 void nes_bmc_420y2k_device::device_start()
@@ -2652,54 +2649,45 @@ void nes_bmc_22games_device::write_h(offs_t offset, u8 data)
 
  Games: 64-in-1 Y2K
 
- In MESS: Supported
+ NES 2.0: mapper 314
+
+ In MAME: Supported.
 
  -------------------------------------------------*/
 
-void nes_bmc_64y2k_device::set_prg()
+void nes_bmc_64y2k_device::update_banks()
 {
-	uint8_t helper1 = m_reg[1] & 0x1f;
+	if (BIT(m_reg[0] & m_reg[1], 7))
-	uint8_t helper2 = (helper1 << 1) | BIT(m_reg[1], 6);
+		prg32(m_reg[1]);
-
-	if (m_reg[0] & 0x80)
-	{
-		if (m_reg[1] & 0x80)
-			prg32(helper1);
-		else
-		{
-			prg16_89ab(helper2);
-			prg16_cdef(helper2);
-		}
-	}
 	else
-		prg16_cdef(helper2);
-}
-
-void nes_bmc_64y2k_device::write_l(offs_t offset, uint8_t data)
-{
-	LOG_MMC(("bmc64y2k write_l, offset: %04x, data: %02x\n", offset, data));
-	offset += 0x100;
-
-	switch (offset)
 	{
-		case 0x1000:
+		u8 bank = m_reg[1] << 1 | BIT(m_reg[1], 6);
-		case 0x1001:
+		prg16_89ab(bank);
-		case 0x1002:
+		prg16_cdef(bank | (BIT(m_reg[0], 7) ? 0 : 7));
-		case 0x1003:
-			m_reg[offset & 0x03] = data;
-			set_prg();
-			chr8(BIT(m_reg[0], 1, 2) | (m_reg[2] << 2), CHRROM);
-			break;
 	}
-	if (offset == 0x1000)   /* write to reg[0] also sets mirroring */
+
-		set_nt_mirroring(BIT(data, 5) ? PPU_MIRROR_HORZ : PPU_MIRROR_VERT);
+	chr8(BIT(m_reg[0], 1, 2) | (m_reg[2] << 2), m_chr_source);
+	set_nt_mirroring(BIT(m_reg[0], 5) ? PPU_MIRROR_HORZ : PPU_MIRROR_VERT);
 }
 
-void nes_bmc_64y2k_device::write_h(offs_t offset, uint8_t data)
+void nes_bmc_64y2k_device::write_l(offs_t offset, u8 data)
 {
-	LOG_MMC(("bmc64y2k write_h, offset: %04x, data: %02x\n", offset, data));
+	LOG_MMC(("bmc_64y2k write_l, offset: %04x, data: %02x\n", offset, data));
 
-	m_reg[3] = data;    // reg[3] is currently unused?!?
+	offset += 0x100;
+	if (offset >= 0x1000)
+	{
+		m_reg[offset & m_reg_mask] = data;
+		update_banks();
+	}
+}
+
+void nes_bmc_64y2k_device::write_h(offs_t offset, u8 data)
+{
+	LOG_MMC(("bmc_64y2k write_h, offset: %04x, data: %02x\n", offset, data));
+
+	if (!BIT(m_reg[0], 7))
+		prg16_89ab(((m_reg[1] << 1) & ~0x07) | (data & 0x07));
 }
 
 /*-------------------------------------------------

src/devices/bus/nes/multigame.h

@@ -798,10 +798,10 @@ class nes_bmc_64y2k_device : public nes_nrom_device
 {
 public:
 	// construction/destruction
-	nes_bmc_64y2k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+	nes_bmc_64y2k_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
 
-	virtual void write_l(offs_t offset, uint8_t data) override;
+	virtual void write_l(offs_t offset, u8 data) override;
-	virtual void write_h(offs_t offset, uint8_t data) override;
+	virtual void write_h(offs_t offset, u8 data) override;
 
 	virtual void pcb_reset() override;
 
@@ -810,8 +810,9 @@ protected:
 	virtual void device_start() override;
 
 private:
-	void set_prg();
+	void update_banks();
-	uint8_t m_reg[4];
+	u8 m_reg[4];
+	u8 m_reg_mask;
 };