New machines marked as NOT_WORKING

----------------------------------
Acorn A500 Development System
Acorn M4
Acorn A680 UNIX Evaluation System

New clones marked as NOT_WORKING
--------------------------------
Acorn A500 Domesday Development System
Acorn R140
Acorn R225
Acorn R260

aa310.cpp:
- Added PC style IO devices (A5000/A4/A3010/A3020).
- Added IDE interface (A5000/A4/A3020).
- Added HD floppy drives (A5000/A4/A3010/A3020).
- RTFM and Vertical Twist joystick interfaces are slot devices.
- Acorn joystick interface (A3010).
- Added Battery Management Unit (A4).
- Partially implemented IOEB (A5000/A4/A3010/A3020).
- Replaced all 8 bit wide ROM images with actual dumps.
- Replaced all default CMOS with factory settings.
- Added printer port to all machines.
- Added serial port to all machines.
- Added podule slots to all machines.
- Added extension ROM socket (A5000/A4).
- Machines are individually configured for floppies and hard discs.
- Added support for Atari ST floppies.

src/devices/machine/acorn_ioc.cpp

@@ -241,7 +241,8 @@ uint32_t acorn_ioc_device::registers_r(offs_t offset, uint32_t mem_mask)
 		return data;
 
 	case KART:
-		change_interrupt(IRQ_STATUS_B, 0x80, CLEAR_LINE);
+		if (!machine().side_effects_disabled())
+			change_interrupt(IRQ_STATUS_B, 0x80, CLEAR_LINE);
 		return m_regs[KART];
 
 	case IRQ_STATUS_A:

src/devices/machine/acorn_memc.cpp

@@ -505,6 +505,15 @@ void acorn_memc_device::high_mem_w(offs_t offset, uint32_t data, uint32_t mem_ma
 		invalid_access(true, addr, data, mem_mask);
 	else if (addr < 0x1000000)   // DRAM
 		m_space->write_dword(dram_address(addr), data, mem_mask);
+	else if (addr < 0x1400000)   // Buffer enabled by IOC
+	{
+		if (ACCESSING_BITS_16_31)
+		{
+			data >>= 16;
+			mem_mask >>= 16;
+		}
+		m_space->write_dword(0x2000000 | addr, data, mem_mask);
+	}
 	else
 		m_space->write_dword(0x2000000 | addr, data, mem_mask);
 }

src/devices/machine/pcf8573.h

@@ -35,13 +35,6 @@
 #include "dirtc.h"
 
 
-/***************************************************************************
-CONSTANTS
-***************************************************************************/
-
-#define PCF8573_SLAVE_ADDRESS ( 0xd0 )
-
-
 //**************************************************************************
 //  TYPE DEFINITIONS
 //**************************************************************************
@@ -77,6 +70,8 @@ protected:
 	virtual void rtc_clock_updated(int year, int month, int day, int day_of_week, int hour, int minute, int second) override;
 
 private:
+	static constexpr uint8_t PCF8573_SLAVE_ADDRESS = 0xd0;
+
 	enum
 	{
 		REG_HOURS               = 0x00,

src/emu/xtal.cpp

@@ -467,6 +467,7 @@ const double XTAL::known_xtals[] = {
 	 80'000'000, /* 80_MHz_XTAL            ARM710 */
 	 87'183'360, /* 87.18336_MHz_XTAL      AT&T 630 MTG */
 	 92'940'500, /* 92.9405_MHz_XTAL       Sun cgthree */
+	 96'000'000, /* 96_MHz_XTAL            Acorn A680 */
 	 99'522'000, /* 99.522_MHz_XTAL        Radius Two Page Display */
 	100'000'000, /* 100_MHz_XTAL           PSX-based Namco System 12, Vegas, Sony ZN1-2-based */
 	101'491'200, /* 101.4912_MHz_XTAL      PSX-based Namco System 10 */

src/mame/mame.lst

@@ -287,14 +287,21 @@ a7800                           // Atari 7800 NTSC
 a7800p                          // Atari 7800 PAL
 
 @source:aa310.cpp
+aa500                           // 1986 Acorn A500
+aa500d                          // 1987 Acorn A500 Domesday
 aa305                           // 1987 Acorn Archimedes 305
 aa310                           // 1987 Acorn Archimedes 310
 aa440                           // 1987 Acorn Archimedes 440
+am4                             // 1987 Acorn M4
+aa680                           // 1988 Acorn A680
+ar140                           // 1988 Acorn R140
 aa3000                          // 1989 Acorn Archimedes 3000
 aa4101                          // 1989 Acorn Archimedes 410/1
 aa4201                          // 1989 Acorn Archimedes 420/1
 aa4401                          // 1989 Acorn Archimedes 440/1
 aa540                           // 1990 Acorn Archimedes 540
+ar225                           // 1990 Acorn R225
+ar260                           // 1990 Acorn R260
 aa5000                          // 1991 Acorn A5000
 aa4                             // 1992 Acorn A4
 aa3010                          // 1992 Acorn A3010