From f3f23f90a3432ea6847515b36df0a62ea7f6f703 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 11 Oct 2022 11:22:34 -0400
Subject: [PATCH] Consolidate repetition in CLR.

---
 .../Implementation/PerformImplementation.hpp  | 27 +++++++++----------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/InstructionSets/M68k/Implementation/PerformImplementation.hpp b/InstructionSets/M68k/Implementation/PerformImplementation.hpp
index 2de88e6ee..fd9b968be 100644
--- a/InstructionSets/M68k/Implementation/PerformImplementation.hpp
+++ b/InstructionSets/M68k/Implementation/PerformImplementation.hpp
@@ -88,10 +88,14 @@ static void add_sub(IntT source, IntT &destination, Status &status) {
 	destination = result;
 }
 
+/// @returns the name of the bit to be used as a mask for BCLR, BCHG, BSET or BTST for
+/// @c instruction given @c source.
 inline uint32_t mask_bit(const Preinstruction &instruction, uint32_t source) {
 	return source & (instruction.mode<1>() == AddressingMode::DataRegisterDirect ? 31 : 7);
 }
 
+/// Performs a BCLR, BCHG or BSET as specified by @c operation and described by @c instruction, @c source and @c destination, updating @c destination and @c status.
+/// Also makes an appropriate notification to the @c flow_controller.
 template <Operation operation, typename FlowController>
 void bit_manipulate(const Preinstruction &instruction, uint32_t source, uint32_t &destination, Status &status, FlowController &flow_controller) {
 	static_assert(operation == Operation::BCLR || operation == Operation::BCHG || operation == Operation::BSET);
@@ -106,6 +110,12 @@ void bit_manipulate(const Preinstruction &instruction, uint32_t source, uint32_t
 	flow_controller.did_bit_op(int(bit));
 }
 
+/// Sets @c destination to 0, clears the overflow, carry and negative flags, sets the zero flag.
+template <typename IntT> void clear(IntT &destination, Status &status) {
+	destination = 0;
+	status.negative_flag = status.overflow_flag = status.carry_flag = status.zero_result = 0;
+}
+
 }
 
 template <
@@ -229,20 +239,9 @@ template <
 			CLRs: store 0 to the destination, set the zero flag, and clear
 			negative, overflow and carry.
 		*/
-		case Operation::CLRb:
-			src.b = 0;
-			status.negative_flag = status.overflow_flag = status.carry_flag = status.zero_result = 0;
-		break;
-
-		case Operation::CLRw:
-			src.w = 0;
-			status.negative_flag = status.overflow_flag = status.carry_flag = status.zero_result = 0;
-		break;
-
-		case Operation::CLRl:
-			src.l = 0;
-			status.negative_flag = status.overflow_flag = status.carry_flag = status.zero_result = 0;
-		break;
+		case Operation::CLRb:	Primitive::clear(src.b, status);	break;
+		case Operation::CLRw:	Primitive::clear(src.w, status);	break;
+		case Operation::CLRl:	Primitive::clear(src.l, status);	break;
 
 		/*
 			CMP.b, CMP.l and CMP.w: sets the condition flags (other than extend) based on a subtraction