From 7445c617bcfa13e3eb7adaabf81ee2926d1625e7 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 9 May 2022 20:32:02 -0400
Subject: [PATCH] Start removing 68000-specific timing calculations.

---
 InstructionSets/M68k/Executor.hpp             |  5 ++-
 .../Implementation/ExecutorImplementation.hpp |  3 +-
 .../Implementation/PerformImplementation.hpp  | 31 ++++++-------------
 InstructionSets/M68k/Instruction.hpp          |  3 +-
 4 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/InstructionSets/M68k/Executor.hpp b/InstructionSets/M68k/Executor.hpp
index 25f83a0c8..2b52b5956 100644
--- a/InstructionSets/M68k/Executor.hpp
+++ b/InstructionSets/M68k/Executor.hpp
@@ -49,8 +49,11 @@ template <Model model, typename BusHandler> class Executor {
 		// Flow control.
 		void consume_cycles(int) {}
 
-		void raise_exception(int, bool use_current_instruction_pc = true);
+		template <bool use_current_instruction_pc = true> void raise_exception(int);
+
 		void did_update_status();
+		template <typename IntT> void did_mulu(IntT) {}
+		template <typename IntT> void did_muls(IntT) {}
 
 		template <typename IntT> void complete_bcc(bool matched_condition, IntT offset);
 		void complete_dbcc(bool matched_condition, bool overflowed, int16_t offset);
diff --git a/InstructionSets/M68k/Implementation/ExecutorImplementation.hpp b/InstructionSets/M68k/Implementation/ExecutorImplementation.hpp
index 6676c1beb..bcf61c4d1 100644
--- a/InstructionSets/M68k/Implementation/ExecutorImplementation.hpp
+++ b/InstructionSets/M68k/Implementation/ExecutorImplementation.hpp
@@ -332,7 +332,8 @@ void Executor<model, BusHandler>::set_state(const Registers &state) {
 // MARK: - Flow Control.
 
 template <Model model, typename BusHandler>
-void Executor<model, BusHandler>::raise_exception(int index, bool use_current_instruction_pc) {
+template <bool use_current_instruction_pc>
+void Executor<model, BusHandler>::raise_exception(int index) {
 	const uint32_t address = index << 2;
 
 	// Grab the status to store, then switch into supervisor mode.
diff --git a/InstructionSets/M68k/Implementation/PerformImplementation.hpp b/InstructionSets/M68k/Implementation/PerformImplementation.hpp
index 352887772..5286eb3c8 100644
--- a/InstructionSets/M68k/Implementation/PerformImplementation.hpp
+++ b/InstructionSets/M68k/Implementation/PerformImplementation.hpp
@@ -492,35 +492,22 @@ template <
 			Multiplications.
 		*/
 
-		case Operation::MULU: {
+		case Operation::MULU:
 			dest.l = dest.w * src.w;
 			status.carry_flag_ = status.overflow_flag_ = 0;
 			status.zero_result_ = dest.l;
 			status.negative_flag_ = status.zero_result_ & 0x80000000;
+			flow_controller.did_mulu(src.w);
+		break;
 
-			int number_of_ones = src.w;
-			convert_to_bit_count_16(number_of_ones);
-
-			// Time taken = 38 cycles + 2 cycles for every 1 in the source.
-			flow_controller.consume_cycles(2 * number_of_ones + 34);
-		} break;
-
-		case Operation::MULS: {
+		case Operation::MULS:
 			dest.l =
 				u_extend16(dest.w) * u_extend16(src.w);
 			status.carry_flag_ = status.overflow_flag_ = 0;
 			status.zero_result_ = dest.l;
 			status.negative_flag_ = status.zero_result_ & 0x80000000;
-
-			// Find the number of 01 or 10 pairs in the 17-bit number
-			// formed by the source value with a 0 suffix.
-			int number_of_pairs = src.w;
-			number_of_pairs = (number_of_pairs ^ (number_of_pairs << 1)) & 0xffff;
-			convert_to_bit_count_16(number_of_pairs);
-
-			// Time taken = 38 cycles + 2 cycles per 1 in the source.
-			flow_controller.consume_cycles(2 * number_of_pairs + 34);
-		} break;
+			flow_controller.did_muls(src.w);
+		break;
 
 		/*
 			Divisions.
@@ -651,12 +638,12 @@ template <
 
 		// TRAP, which is a nicer form of ILLEGAL.
 		case Operation::TRAP:
-			flow_controller.raise_exception(src.l + 32, false);
+			flow_controller.template raise_exception<false>(src.l + 32);
 		break;
 
 		case Operation::TRAPV: {
 			if(status.overflow_flag_) {
-				flow_controller.raise_exception(7, false);
+				flow_controller.template raise_exception<false>(7);
 			}
 		} break;
 
@@ -682,7 +669,7 @@ template <
 				} else {
 					flow_controller.consume_cycles(12);
 				}
-				flow_controller.raise_exception(6, false);
+				flow_controller.template raise_exception<false>(6);
 			}
 		} break;
 
diff --git a/InstructionSets/M68k/Instruction.hpp b/InstructionSets/M68k/Instruction.hpp
index 5753a483c..77e0ffed2 100644
--- a/InstructionSets/M68k/Instruction.hpp
+++ b/InstructionSets/M68k/Instruction.hpp
@@ -157,7 +157,8 @@ static constexpr uint8_t StoreOp2	= (1 << 3);
 
 /*!
 	Provides a bitfield with a value in the range 0–15 indicating which of the provided operation's
-	operands are accessed via standard fetch and store cycles.
+	operands are accessed via standard fetch and store cycles; the bitfield is composted of
+	[Fetch/Store]Op[1/2] as defined above.
 
 	Unusual bus sequences, such as TAS or MOVEM, are not described here.
 */