From a970b50ed1f122c9ea60054fb9602db858b589d2 Mon Sep 17 00:00:00 2001
From: Olivier Galibert <galibert@pobox.com>
Date: Fri, 3 Mar 2017 08:14:18 +0100
Subject: [PATCH] atm: Remove direct update handler.  Still not working, but
 less badly [O. Galibert]

---
 src/mame/drivers/atm.cpp | 88 ++++++++++++++++++----------------------
 1 file changed, 39 insertions(+), 49 deletions(-)

diff --git a/src/mame/drivers/atm.cpp b/src/mame/drivers/atm.cpp
index 90742ae87fb..b06e3e5eaeb 100644
--- a/src/mame/drivers/atm.cpp
+++ b/src/mame/drivers/atm.cpp
@@ -6,9 +6,6 @@ MicroART ATM (clone of Spectrum)
 
 Not working because of banking issues.
 
-The direct_update_handler needs rewriting, because removing it allows the
-computer to boot up (with keyboard problems).
-
 *******************************************************************************************/
 
 #include "emu.h"
@@ -33,7 +30,9 @@ public:
 	{ }
 
 	DECLARE_WRITE8_MEMBER(atm_port_7ffd_w);
-	DIRECT_UPDATE_MEMBER(atm_direct);
+	DECLARE_READ8_MEMBER(beta_neutral_r);
+	DECLARE_READ8_MEMBER(beta_enable_r);
+	DECLARE_READ8_MEMBER(beta_disable_r);
 	DECLARE_MACHINE_RESET(atm);
 
 protected:
@@ -44,48 +43,11 @@ protected:
 	required_device<beta_disk_device> m_beta;
 
 private:
+	address_space *m_program;
 	uint8_t *m_p_ram;
 	void atm_update_memory();
 };
 
-
-DIRECT_UPDATE_MEMBER(atm_state::atm_direct)
-{
-	uint16_t pc = m_maincpu->state_int(STATE_GENPCBASE);
-
-	if (m_beta->started() && m_beta->is_active())
-	{
-		if (pc >= 0x4000)
-		{
-			m_ROMSelection = BIT(m_port_7ffd_data, 4);
-			m_beta->disable();
-			m_bank1->set_base(&m_p_ram[0x10000 + (m_ROMSelection<<14)]);
-		}
-	}
-	else if (((pc & 0xff00) == 0x3d00) && (m_ROMSelection==1))
-	{
-		m_ROMSelection = 3;
-		if (m_beta->started())
-			m_beta->enable();
-
-	}
-	if(address<=0x3fff)
-	{
-		if (m_ROMSelection == 3)
-		{
-			direct.explicit_configure(0x0000, 0x3fff, 0x3fff, &m_p_ram[0x18000]);
-			m_bank1->set_base(&m_p_ram[0x18000]);
-		}
-		else
-		{
-			direct.explicit_configure(0x0000, 0x3fff, 0x3fff, &m_p_ram[0x10000 + (m_ROMSelection<<14)]);
-			m_bank1->set_base(&m_p_ram[0x10000 + (m_ROMSelection<<14)]);
-		}
-		return ~0;
-	}
-	return address;
-}
-
 void atm_state::atm_update_memory()
 {
 	uint8_t *messram = m_ram->pointer();
@@ -117,6 +79,33 @@ WRITE8_MEMBER(atm_state::atm_port_7ffd_w)
 	atm_update_memory();
 }
 
+READ8_MEMBER(atm_state::beta_neutral_r)
+{
+	return m_program->read_byte(offset);
+}
+
+READ8_MEMBER(atm_state::beta_enable_r)
+{
+	if(m_ROMSelection == 1) {
+		m_ROMSelection = 3;
+		if (m_beta->started()) {
+			m_beta->enable();
+			m_bank1->set_base(&m_p_ram[0x18000]);
+		}
+	}
+	return m_program->read_byte(offset + 0x3d00);
+}
+
+READ8_MEMBER(atm_state::beta_disable_r)
+{
+	if (m_beta->started() && m_beta->is_active()) {
+		m_ROMSelection = BIT(m_port_7ffd_data, 4);
+		m_beta->disable();
+		m_bank1->set_base(&m_p_ram[0x10000 + (m_ROMSelection<<14)]);
+	}
+	return m_program->read_byte(offset + 0x4000);
+}
+
 static ADDRESS_MAP_START (atm_io, AS_IO, 8, atm_state )
 	ADDRESS_MAP_UNMAP_HIGH
 	AM_RANGE(0x001f, 0x001f) AM_DEVREADWRITE(BETA_DISK_TAG, beta_disk_device, status_r, command_w) AM_MIRROR(0xff00)
@@ -130,20 +119,20 @@ static ADDRESS_MAP_START (atm_io, AS_IO, 8, atm_state )
 	AM_RANGE(0xc000, 0xc000) AM_DEVREADWRITE("ay8912", ay8910_device, data_r, address_w) AM_MIRROR(0x3ffd)
 ADDRESS_MAP_END
 
+static ADDRESS_MAP_START (atm_switch, AS_DECRYPTED_OPCODES, 8, atm_state)
+	AM_RANGE(0x3d00, 0x3dff) AM_READ(beta_enable_r)
+	AM_RANGE(0x0000, 0x3fff) AM_READ(beta_neutral_r) // Overlap with previous because we want real addresses on the 3e00-3fff range
+	AM_RANGE(0x4000, 0xffff) AM_READ(beta_disable_r)
+ADDRESS_MAP_END
+
 MACHINE_RESET_MEMBER(atm_state,atm)
 {
 	uint8_t *messram = m_ram->pointer();
-	address_space &space = m_maincpu->space(AS_PROGRAM);
+	m_program = &m_maincpu->space(AS_PROGRAM);
 	m_p_ram = memregion("maincpu")->base();
 
-	space.install_read_bank(0x0000, 0x3fff, "bank1");
-	space.unmap_write(0x0000, 0x3fff);
-
 	if (m_beta->started())
-	{
 		m_beta->enable();
-	}
-	space.set_direct_update_handler(direct_update_delegate(&atm_state::atm_direct, this));
 
 	memset(messram,0,128*1024);
 
@@ -185,6 +174,7 @@ GFXDECODE_END
 static MACHINE_CONFIG_DERIVED_CLASS( atm, spectrum_128, atm_state )
 	MCFG_CPU_MODIFY("maincpu")
 	MCFG_CPU_IO_MAP(atm_io)
+	MCFG_CPU_DECRYPTED_OPCODES_MAP(atm_switch)
 	MCFG_MACHINE_RESET_OVERRIDE(atm_state, atm )
 
 	MCFG_BETA_DISK_ADD(BETA_DISK_TAG)