(MESS) nes: added support for Multi-Discrete PCB (aka Mapper 28) used

by Action 53 - Function 16 - Volume ONE - "Streemerz Bundle" homebrew
multicart. [Fabio Priuli]

.gitattributes

@@ -8126,6 +8126,8 @@ src/mess/machine/ne1000.h svneol=native#text/plain
 src/mess/machine/ne2000.c svneol=native#text/plain
 src/mess/machine/ne2000.h svneol=native#text/plain
 src/mess/machine/nes.c svneol=native#text/plain
+src/mess/machine/nes_act53.c svneol=native#text/plain
+src/mess/machine/nes_act53.h svneol=native#text/plain
 src/mess/machine/nes_ave.c svneol=native#text/plain
 src/mess/machine/nes_ave.h svneol=native#text/plain
 src/mess/machine/nes_bandai.c svneol=native#text/plain

src/mess/drivers/nes.c

@@ -1016,6 +1016,7 @@ SLOT_INTERFACE_START(nes_cart)
 	SLOT_INTERFACE_INTERNAL("bmc_830118c",      NES_BMC_830118C)
 	SLOT_INTERFACE_INTERNAL("pjoy84",           NES_PJOY84)
 	SLOT_INTERFACE_INTERNAL("nocash_nochr",     NES_NOCHR)
+	SLOT_INTERFACE_INTERNAL("nes_action53",     NES_ACTION53)
 // other unsupported...
 	SLOT_INTERFACE_INTERNAL("ninjaryu",         NES_NROM)    // mapper 111 - UNSUPPORTED
 	SLOT_INTERFACE_INTERNAL("unl_dance",        NES_NROM)    // UNSUPPORTED

src/mess/includes/nes.h

@@ -33,6 +33,7 @@
 #include "machine/nes_sunsoft_dcs.h"
 #include "machine/nes_taito.h"
 // unlicensed/bootleg/pirate PCBs
+#include "machine/nes_act53.h"
 #include "machine/nes_ave.h"
 #include "machine/nes_benshieng.h"
 #include "machine/nes_camerica.h"

src/mess/machine/nes_act53.c

@@ -0,0 +1,207 @@
+/***********************************************************************************************************
+
+
+ NES/Famicom cartridge emulation for Action 53
+
+ Copyright MESS Team.
+ Visit http://mamedev.org for licensing and usage restrictions.
+
+
+ Here we emulate the Multi-Discrete PCB designed by Tepples for 
+ this homebew multicart [mapper 28]
+
+ ***********************************************************************************************************/
+
+
+#include "emu.h"
+#include "machine/nes_act53.h"
+
+
+#ifdef NES_PCB_DEBUG
+#define VERBOSE 1
+#else
+#define VERBOSE 0
+#endif
+
+#define LOG_MMC(x) do { if (VERBOSE) logerror x; } while (0)
+
+
+//-------------------------------------------------
+//  constructor
+//-------------------------------------------------
+
+const device_type NES_ACTION53 = &device_creator<nes_action53_device>;
+
+
+nes_action53_device::nes_action53_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+					: nes_nrom_device(mconfig, NES_ACTION53, "NES Cart Action 53 PCB", tag, owner, clock, "nes_action53", __FILE__)
+{
+}
+
+
+
+void nes_action53_device::device_start()
+{
+	common_start();
+	save_item(NAME(m_sel));
+	save_item(NAME(m_reg));
+	m_reg[0] = 0x00;
+	m_reg[1] = 0x0f;
+	m_reg[2] = 0x00;
+	m_reg[3] = 0x3f;
+}
+
+void nes_action53_device::pcb_reset()
+{
+	m_chr_source = m_vrom_chunks ? CHRROM : CHRRAM;
+	// register content is not touched by reset
+	update_prg();
+}
+
+
+/*-------------------------------------------------
+ mapper specific handlers
+ -------------------------------------------------*/
+
+/*-------------------------------------------------
+
+ Board ACTION 53
+
+ In MESS: *VERY* preliminary support. 
+ 
+ This board uses 4 registers (reg is selected by writes to 0x5xxx)
+ Info from nesdev wiki
+ 
+ R:$00:  [...M ..CC]
+     C = CHR Reg
+     M = Mirroring
+         This bit overwrites bit 0 of R:$80, but only if bit 1 of
+         R:$80 is clear
+ 
+ R:$01:  [...M PPPP]
+     P = PRG Reg
+     M = Mirroring
+         This bit overwrites bit 0 of R:$80, but only if bit 1 of
+         R:$80 is clear
+ 
+ R:$80:  [..GG PSMM]
+     G = Game Size (0=32K, 1=64K, 2=128K, 3=256K)
+     P = PRG Size (0=32k mode, 1=16k mode)
+     S = Slot select:
+         0 = $C000 swappable, $8000 fixed to bottom of 32K outer bank
+         1 = $8000 swappable, $C000 fixed to top of 32K outer bank
+         This bit is ignored when 'P' is clear (32k mode)
+     M = Mirroring control:
+         %00 = 1ScA
+         %01 = 1ScB
+         %10 = Vert
+         %11 = Horz
+
+ R:$81:  [..BB BBBB]
+     Outer PRG Reg
+
+
+ -------------------------------------------------*/
+
+void nes_action53_device::update_prg()
+{
+	UINT8 prg_lo = 0, prg_hi = 0, helper = 0;
+	UINT8 out = (m_reg[3] & 0x3f) << 1;		// Outer PRG reg
+	UINT8 size = (m_reg[2] & 0x30) >> 4;	// Game size
+	UINT8 mask = (1 << (size + 1)) - 1;		// Bits to be taken from PRG reg
+
+	if (!BIT(m_reg[2], 3))
+	{
+		helper = (out & ~mask) | ((m_reg[1] << 1) & mask);
+		//32K mode
+		prg_lo = (helper & 0xfe);
+		prg_hi = (helper | 0x01);
+	}
+	else
+	{
+		helper = (out & ~mask) | (m_reg[1] & mask);
+		if (BIT(m_reg[2], 2))
+		{
+			//16K mode with fixed HI
+			prg_lo = helper;
+			prg_hi = (out | 0x01);
+		}
+		else
+		{
+			//16K mode with fixed LO
+			prg_lo = (out & 0xfe);
+			prg_hi = helper;
+		}
+	}
+
+//	printf("banks : 0x%2X - 0x%2X\n", prg_lo, prg_hi);
+	prg16_89ab(prg_lo);
+	prg16_cdef(prg_hi);
+}
+
+void nes_action53_device::update_mirr()
+{
+	switch (m_reg[2] & 0x03)
+	{
+		case 0:
+			set_nt_mirroring(PPU_MIRROR_LOW);
+			break;
+		case 1:
+			set_nt_mirroring(PPU_MIRROR_HIGH);
+			break;
+		case 2:
+			set_nt_mirroring(PPU_MIRROR_VERT);
+			break;
+		case 3:
+			set_nt_mirroring(PPU_MIRROR_HORZ);
+			break;
+	}
+}
+
+WRITE8_MEMBER(nes_action53_device::write_l)
+{
+	LOG_MMC(("action 53 write_l, offset: %04x, data: %02x\n", offset, data));
+	offset += 0x100;
+	if (offset >= 0x1000)
+		m_sel = BIT(data, 0) | (BIT(data, 7) << 1);
+}
+
+
+WRITE8_MEMBER(nes_action53_device::write_h)
+{
+	LOG_MMC(("action 53 write_h, offset: %04x, data: %02x\n", offset, data));
+
+	if (m_reg[m_sel] != data)
+	{
+		m_reg[m_sel] = data;
+
+		switch (m_sel)
+		{
+			case 0:
+				if (!BIT(m_reg[2],1))
+				{
+					m_reg[2] &= 0xfe;
+					m_reg[2] |= BIT(data,4);
+					update_mirr();
+				}
+				chr8(m_reg[0] & 0x03, m_chr_source);
+				break;
+			case 1:
+				if (!BIT(m_reg[2],1))
+				{
+					m_reg[2] &= 0xfe;
+					m_reg[2] |= BIT(data,4);
+					update_mirr();
+				}
+				update_prg();
+				break;
+			case 2:
+				update_prg();
+				update_mirr();
+				break;
+			case 3:
+				update_prg();
+				break;
+		}
+	}
+}

src/mess/machine/nes_act53.h

@@ -0,0 +1,36 @@
+#ifndef __NES_ACTION53_H
+#define __NES_ACTION53_H
+
+#include "machine/nes_nxrom.h"
+
+
+// ======================> nes_racermate_device
+
+class nes_action53_device : public nes_nrom_device
+{
+public:
+	// construction/destruction
+	nes_action53_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
+
+	// device-level overrides
+	virtual void device_start();
+	virtual DECLARE_WRITE8_MEMBER(write_l);
+	virtual DECLARE_WRITE8_MEMBER(write_h);
+
+	virtual void pcb_reset();
+
+private:
+	void update_prg();
+	void update_mirr();
+	UINT8 m_sel;
+	UINT8 m_reg[4];
+};
+
+
+
+
+
+// device type definition
+extern const device_type NES_ACTION53;
+
+#endif

src/mess/machine/nes_ines.inc

@@ -57,7 +57,7 @@ static const nes_mmc mmc_list[] =
 	{ 25, KONAMI_VRC4 },
 	{ 26, KONAMI_VRC6 },
 	{ 27, UNL_WORLDHERO },	// 27 World Hero board - Unsupported
-	// 28 Unused
+	{ 28, BTL_ACTION53 },	// 28 - Multi-discrete PCB designed by Tepples for Action 53
 	// 29 Unused
 	// 30 Unused
 	// 31 Unused

src/mess/machine/nes_pcb.inc

@@ -300,6 +300,7 @@ static const nes_pcb pcb_list[] =
 	{ "tf1201",           UNL_TF1201 },
 	{ "unl_cfight",       UNL_CITYFIGHT },
 	{ "nocash_nochr",     NOCASH_NOCHR },
+	{ "nes_action53",     BTL_ACTION53 },
 	{ "ffe3",             FFE3_BOARD },
 	{ "ffe4",             FFE4_BOARD },
 	{ "ffe8",             FFE8_BOARD },

src/mess/machine/nes_slot.h

@@ -120,6 +120,7 @@ enum
 	KAY_BOARD, HOSENKAN_BOARD, NITRA_TDA, GOUDER_37017, NANJING_BOARD,
 	WHIRLWIND_2706,
 	NOCASH_NOCHR,	// homebrew PCB design which uses NTRAM for CHRRAM
+	BTL_ACTION53,	// homebrew PCB for homebrew multicarts
 	/* FFE boards, for mappers 6, 8, 17 */
 	FFE3_BOARD, FFE4_BOARD, FFE8_BOARD, TEST_BOARD,
 	/* Unsupported (for place-holder boards, with no working emulation) & no-board (at init) */

src/mess/mess.mak

@@ -1535,6 +1535,7 @@ $(MESSOBJ)/nintendo.a:          \
 	$(MESS_MACHINE)/nes_mmc3.o  \
 	$(MESS_MACHINE)/nes_mmc3_clones.o  \
 	$(MESS_MACHINE)/nes_mmc5.o  \
+	$(MESS_MACHINE)/nes_act53.o  \
 	$(MESS_MACHINE)/nes_ave.o  \
 	$(MESS_MACHINE)/nes_bandai.o  \
 	$(MESS_MACHINE)/nes_benshieng.o  \