From 780954f27b199f1bfbdcce44038c8eb957b16134 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 24 May 2022 15:14:20 -0400
Subject: [PATCH] Add TRAP, TRAPV.

---
 .../Implementation/68000Mk2Implementation.hpp | 32 +++++++++++++++----
 .../Implementation/68000Mk2Storage.hpp        |  2 +-
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
index 1350b2571..cacfbb2cd 100644
--- a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
+++ b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
@@ -17,13 +17,7 @@
 namespace CPU {
 namespace MC68000Mk2 {
 
-// TODO: BERR, interrupt inputs, etc; and obeying the trace flag.
-// Also, from Instruction.hpp:
-//
-//	TRAP, TRAPV
-//
-// Not provided by a 68000: Bccl, BSRl
-
+// TODO: obeyance of the trace flag, the address/bus error exception.
 
 /// States for the state machine which are named by
 /// me for their purpose rather than automatically by file position.
@@ -183,6 +177,8 @@ enum ExecutionState: int {
 	RESET,
 	NOP,
 	STOP,
+	TRAP,
+	TRAPV,
 };
 
 // MARK: - The state machine.
@@ -880,6 +876,9 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
 
 				SpecialCASE(STOP);
 
+				SpecialCASE(TRAP);
+				SpecialCASE(TRAPV);
+
 				default:
 					assert(false);
 			}
@@ -2274,6 +2273,25 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
 			Prefetch();
 		MoveToStateSpecific(Decode);
 
+		//
+		// TRAP, TRAPV
+		//
+
+		// TODO: which program counter is appropriate for TRAP? That of the TRAP,
+		// or that of the instruction after?
+		BeginState(TRAP):
+			IdleBus(2);
+			exception_vector_ = (opcode_ & 15) + InstructionSet::M68k::Exception::TrapBase;
+		MoveToStateSpecific(StandardException);
+
+		BeginState(TRAPV):
+			Prefetch();
+			if(!status_.overflow_flag) {
+				MoveToStateSpecific(Decode);
+			}
+			exception_vector_ = InstructionSet::M68k::Exception::TRAPV;
+		MoveToStateSpecific(StandardException);
+
 		//
 		// Various states TODO.
 		//
diff --git a/Processors/68000Mk2/Implementation/68000Mk2Storage.hpp b/Processors/68000Mk2/Implementation/68000Mk2Storage.hpp
index 09b27818d..25ad1e8bd 100644
--- a/Processors/68000Mk2/Implementation/68000Mk2Storage.hpp
+++ b/Processors/68000Mk2/Implementation/68000Mk2Storage.hpp
@@ -150,7 +150,6 @@ struct ProcessorBase: public InstructionSet::M68k::NullFlowController {
 	template <typename IntT> void complete_bcc(bool, IntT);
 	inline void complete_dbcc(bool, bool, int16_t);
 	inline void bsr(uint32_t);
-	inline void stop() {}							// TODO
 	inline void move_to_usp(uint32_t);
 	inline void move_from_usp(uint32_t &);
 	inline void tas(Preinstruction, uint32_t);
@@ -170,6 +169,7 @@ struct ProcessorBase: public InstructionSet::M68k::NullFlowController {
 	inline void rte() {}
 	inline void rts() {}
 	inline void reset() {}
+	inline void stop() {}
 
 	// Some microcycles that will be modified as required and used in the main loop;
 	// the semantics of a switch statement make in-place declarations awkward and