From 933c779ab69c5b71a9d552640c980f8dd90e64bd Mon Sep 17 00:00:00 2001
From: kazblox <kazbloxmc@gmail.com>
Date: Sun, 25 Oct 2015 12:09:19 -0400
Subject: [PATCH 1/2] i86 - implement 0xF1 alias for 0xF0 (LOCK)

opcode tested on reenigne's IBM XT bus sniffer.
---
 src/devices/cpu/i86/i86.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/devices/cpu/i86/i86.c b/src/devices/cpu/i86/i86.c
index 9c8d5a75465..5921ce3e052 100644
--- a/src/devices/cpu/i86/i86.c
+++ b/src/devices/cpu/i86/i86.c
@@ -1147,9 +1147,10 @@ bool i8086_common_cpu_device::common_op(UINT8 op)
 			CLK(POP_R16);
 			break;
 
-// 8086 'invalid opcodes', as documented at http://www.os2museum.com/wp/?p=2147
-// - 0x60 - 0x6f are an alias to 0x70 - 0x7f.
+// 8086 'invalid opcodes', as documented at http://www.os2museum.com/wp/?p=2147 and tested on real hardware
+// - 0x60 - 0x6f are aliases to 0x70 - 0x7f.
 // - 0xc0,  0xc1, 0xc8, 0xc9 are also aliases where the CPU ignores BIT 1 (*).
+// - 0xf1 is an alias to 0xf0.
 //
 //      Instructions are used in the boot sector for some versions of
 //      MS-DOS  (e.g. the DEC Rainbow-100 version of DOS 2.x)
@@ -1692,7 +1693,7 @@ bool i8086_common_cpu_device::common_op(UINT8 op)
 			}
 			break;
 
-		case 0xc1: //  0xc1 is 0xc3 - see (*)
+		case 0xc1: // 0xc1 is 0xc3 - see (*)
 		case 0xc3: // i_ret
 			m_ip = POP();
 			CLK(RET_NEAR);
@@ -1724,7 +1725,7 @@ bool i8086_common_cpu_device::common_op(UINT8 op)
 			CLKM(MOV_RI16,MOV_MI16);
 			break;
 
-		case 0xc8:  // 0xc8 = 0xca - see (*)
+		case 0xc8: // 0xc8 = 0xca - see (*)
 		case 0xca: // i_retf_d16
 			{
 				UINT32 count = fetch_word();
@@ -1735,7 +1736,7 @@ bool i8086_common_cpu_device::common_op(UINT8 op)
 			}
 			break;
 
-		case 0xc9:  // 0xc9 = 0xcb  - see (*)
+		case 0xc9: // 0xc9 = 0xcb  - see (*)
 		case 0xcb: // i_retf
 			m_ip = POP();
 			m_sregs[CS] = POP();
@@ -2017,6 +2018,7 @@ bool i8086_common_cpu_device::common_op(UINT8 op)
 
 
 		case 0xf0: // i_lock
+		case 0xf1: // 0xf1 is 0xf0; verified on custom hardware
 			logerror("%s: %06x: Warning - BUSLOCK\n", tag(), pc());
 			m_lock = true;
 			m_no_interrupt = 1;

From f6f13202fe28bd31dda4140d9617e721ca8d6204 Mon Sep 17 00:00:00 2001
From: kazblox <kazbloxmc@gmail.com>
Date: Sun, 25 Oct 2015 12:14:48 -0400
Subject: [PATCH 2/2] cosmic.c - correct magspot clock

verified via schematics
---
 src/mame/drivers/cosmic.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/mame/drivers/cosmic.c b/src/mame/drivers/cosmic.c
index 5468258b1a6..5cc6b4be15d 100644
--- a/src/mame/drivers/cosmic.c
+++ b/src/mame/drivers/cosmic.c
@@ -978,7 +978,7 @@ MACHINE_RESET_MEMBER(cosmic_state,cosmicg)
 static MACHINE_CONFIG_START( cosmic, cosmic_state )
 
 	/* basic machine hardware */
-	MCFG_CPU_ADD("maincpu", Z80,Z80_MASTER_CLOCK/6) /* 1.8026 MHz*/
+	MCFG_CPU_ADD("maincpu", Z80,Z80_MASTER_CLOCK/6) /* 1.8026 MHz */
 
 	MCFG_MACHINE_START_OVERRIDE(cosmic_state,cosmic)
 	MCFG_MACHINE_RESET_OVERRIDE(cosmic_state,cosmic)
@@ -1099,7 +1099,7 @@ MACHINE_CONFIG_END
 static MACHINE_CONFIG_DERIVED( magspot, cosmic )
 
 	/* basic machine hardware */
-	MCFG_CPU_MODIFY("maincpu")
+	MCFG_CPU_REPLACE("maincpu", Z80, Z80_MASTER_CLOCK/4) /* 2.704 MHz, verified via schematics */
 	MCFG_CPU_PROGRAM_MAP(magspot_map)
 
 	/* video hardware */