From f4db841a2e70e0f4bf440b912de717c72d445a5f Mon Sep 17 00:00:00 2001
From: Olivier Galibert <galibert@pobox.com>
Date: Wed, 24 Aug 2016 23:07:14 +0200
Subject: [PATCH] dirom,okim6295: Add/fix banking support.  Better okim fix
 post-release [O. Galibert]

---
 src/devices/sound/okim6295.cpp | 16 +--------------
 src/emu/dirom.cpp              | 36 +++++++++++++++++++++++++++-------
 src/emu/dirom.h                |  6 ++++++
 3 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/src/devices/sound/okim6295.cpp b/src/devices/sound/okim6295.cpp
index f5b2490fb52..7926687b879 100644
--- a/src/devices/sound/okim6295.cpp
+++ b/src/devices/sound/okim6295.cpp
@@ -196,21 +196,7 @@ void okim6295_device::set_bank_base(offs_t base, bool bDontUpdateStream)
 	{
 		m_stream->update();
 	}
-
-	// if we are setting a non-zero base, and we have no bank, allocate one
-	if (!m_bank_installed && base != 0)
-	{
-		// override our memory map with a bank
-		space().install_read_bank(0x00000, 0x3ffff, tag());
-		m_bank_installed = true;
-	}
-
-	// if we have a bank number, set the base pointer
-	if (m_bank_installed)
-	{
-		m_bank_offs = base;
-		membank(tag())->set_base(m_region->base() + base);
-	}
+	set_rom_bank(base / 0x40000);
 }
 
 
diff --git a/src/emu/dirom.cpp b/src/emu/dirom.cpp
index 45a4dd2dc56..a055ce00539 100644
--- a/src/emu/dirom.cpp
+++ b/src/emu/dirom.cpp
@@ -16,17 +16,35 @@ const address_space_config *device_rom_interface::memory_space_config(address_sp
     return spacenum ? nullptr : &m_rom_config;
 }
 
+void device_rom_interface::set_rom_bank(int bank)
+{
+	if(!m_bank)
+		emu_fatalerror("%s: device_rom_interface::set_rom_bank called without banking setup", device().tag());
+
+	m_cur_bank = bank;
+	m_bank->set_entry(bank);
+}
+
+void device_rom_interface::reset_bank()
+{
+	if(m_bank)
+		m_bank->set_entry(m_cur_bank);
+}
+
 void device_rom_interface::set_rom(const void *base, UINT32 size)
 {
 	UINT32 mend = m_rom_config.addr_width() == 32 ? 0xffffffff : (1 << m_rom_config.addr_width()) - 1;
 	UINT32 rend = size-1;
-	if(rend > mend) {
-		device().logerror("Warning: The rom for device %s is %x bytes, while the chip addressing space is only %x bytes.\n", device().tag(), rend+1, mend+1);
-		rend = mend;
-	}
-	if(rend == mend)
-		space().install_rom(0, mend, const_cast<void *>(base));
-	else {
+	UINT32 banks = (rend+1) / (mend+1);
+	if(banks < 1)
+		banks = 1;
+
+	if(rend >= mend) {
+		space().install_read_bank(0, mend, device().tag());
+		m_bank = device().machine().memory().banks().find(device().tag())->second.get();
+		m_bank->configure_entries(0, banks, const_cast<void *>(base), mend+1);
+
+	} else {
 		// Round up to the nearest power-of-two-minus-one
 		UINT32 rmask = rend;
 		rmask |= rmask >> 1;
@@ -45,6 +63,10 @@ void device_rom_interface::set_rom(const void *base, UINT32 size)
 void device_rom_interface::interface_pre_start()
 {
 	m_rom_direct = &space().direct();
+	m_bank = nullptr;
+	m_cur_bank = -1;
+	device().save_item(NAME(m_cur_bank));
+	device().machine().save().register_postload(save_prepost_delegate(FUNC(device_rom_interface::reset_bank), this));
 
 	if(!has_configured_map(0)) {
 		memory_region *reg = device().memregion(DEVICE_SELF);
diff --git a/src/emu/dirom.h b/src/emu/dirom.h
index 900b5a09517..b09d32c502a 100644
--- a/src/emu/dirom.h
+++ b/src/emu/dirom.h
@@ -29,11 +29,15 @@ public:
 	inline UINT64 read_qword(offs_t byteaddress) { return m_rom_direct->read_qword(byteaddress); }
 
 	void set_rom(const void *base, UINT32 size);
+	void set_rom_bank(int bank);
 
 private:
 	const address_space_config m_rom_config;
 	direct_read_data *m_rom_direct;
 
+	memory_bank *m_bank;
+	int m_cur_bank;
+
 	virtual const address_space_config *memory_space_config(address_spacenum spacenum) const override;
 	virtual void interface_pre_start() override;
 
@@ -41,6 +45,8 @@ private:
 	DECLARE_READ16_MEMBER(z16_r);
 	DECLARE_READ32_MEMBER(z32_r);
 	DECLARE_READ64_MEMBER(z64_r);
+
+	void reset_bank();
 };
 
 #endif