From 4b1324de7756f3b823b4be4ae16b21c4f4819385 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sun, 28 Apr 2019 15:52:58 -0400
Subject: [PATCH] Takes a run at TRAPV.

... to leave 1466 as the unimplemented count.
---
 .../68000/Implementation/68000Implementation.hpp       | 10 ++++++++++
 Processors/68000/Implementation/68000Storage.cpp       |  8 ++++++++
 Processors/68000/Implementation/68000Storage.hpp       |  2 +-
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/Processors/68000/Implementation/68000Implementation.hpp b/Processors/68000/Implementation/68000Implementation.hpp
index 2b73a16e1..af467a1aa 100644
--- a/Processors/68000/Implementation/68000Implementation.hpp
+++ b/Processors/68000/Implementation/68000Implementation.hpp
@@ -953,6 +953,16 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 									program_counter_.full -= 2;
 								} break;
 
+								case Operation::TRAPV: {
+									if(overflow_flag_) {
+										// Select the trap steps as next; the initial microcycle should be 4 cycles long.
+										bus_program = trap_steps_;
+										bus_program->microcycle.length = HalfCycles(0);
+										populate_trap_steps(7, get_status());
+										program_counter_.full -= 4;
+									}
+								} break;
+
 								case Operation::CHK: {
 									const bool is_under = int16_t(active_program_->destination->halves.low.full) < 0;
 									const bool is_over = int16_t(active_program_->destination->halves.low.full) > int16_t(active_program_->source->halves.low.full);
diff --git a/Processors/68000/Implementation/68000Storage.cpp b/Processors/68000/Implementation/68000Storage.cpp
index 314d1924e..1f5cf2ddc 100644
--- a/Processors/68000/Implementation/68000Storage.cpp
+++ b/Processors/68000/Implementation/68000Storage.cpp
@@ -447,6 +447,7 @@ struct ProcessorStorageConstructor {
 			MOVEUSP,					// Maps a direction and register to a MOVE [to/from] USP.
 
 			TRAP,						// Maps to a TRAP.
+			TRAPV,						// Maps to a TRAPV.
 			CHK,						// Maps to a CHK.
 
 			NOP,						// Maps to a NOP.
@@ -665,6 +666,7 @@ struct ProcessorStorageConstructor {
 			{0xfff0, 0x4e60, Operation::MOVEAl, Decoder::MOVEUSP},				// 6-21 (p475)
 
 			{0xfff0, 0x4e40, Operation::TRAP, Decoder::TRAP},					// 4-188 (p292)
+			{0xffff, 0x4e76, Operation::TRAPV, Decoder::TRAPV},					// 4-191 (p295)
 			{0xf1c0, 0x4180, Operation::CHK, Decoder::CHK},						// 4-69 (p173)
 
 			{0xffff, 0x4e77, Operation::RTE_RTR, Decoder::RTE_RTR},				// 4-168 (p272) [RTR]
@@ -3213,6 +3215,12 @@ struct ProcessorStorageConstructor {
 							op();
 						} break;
 
+						case Decoder::TRAPV: {
+							op(Action::None, seq("np"));
+							op(Action::PerformOperation);
+							op();
+						} break;
+
 						case Decoder::CHK: {
 							storage_.instructions[instruction].set_destination(storage_, Dn, data_register);
 							storage_.instructions[instruction].set_source(storage_, ea_mode, ea_register);
diff --git a/Processors/68000/Implementation/68000Storage.hpp b/Processors/68000/Implementation/68000Storage.hpp
index 62e8d7945..76760f4b5 100644
--- a/Processors/68000/Implementation/68000Storage.hpp
+++ b/Processors/68000/Implementation/68000Storage.hpp
@@ -104,7 +104,7 @@ class ProcessorStorage {
 
 			RTE_RTR,
 
-			TRAP,
+			TRAP,	TRAPV,
 			CHK,
 
 			EXG,	SWAP,