Rename Table.h; LogSin -> LogSign and make it a bit more typer.

Components/OPL2/Implementation/Channel.cpp

@@ -7,7 +7,6 @@
 //
 
 #include "Channel.hpp"
-#include "Tables.h"
 
 using namespace Yamaha::OPL;
 

Components/OPL2/Implementation/Operator.cpp

@@ -9,12 +9,11 @@
 #include "Operator.hpp"
 
 #include <algorithm>
-#include "Tables.h"
 
 using namespace Yamaha::OPL;
 
 int OperatorState::level() {
-	return power_two(attenuation.logsin) * attenuation.sign;
+	return power_two(attenuation);
 }
 
 void Operator::set_attack_decay(uint8_t value) {
@@ -179,10 +178,10 @@ void Operator::update(OperatorState &state, bool key_on, int channel_period, int
 		// Overrides here represent per-channel volume on an OPLL. The bits are defined to represent
 		// attenuations of 24db to 3db; the main envelope generator is stated to have a resolution of
 		// 0.325db (which I've assumed is supposed to say 0.375db).
-		state.attenuation.logsin += state.adsr_attenuation_ + (overrides->attenuation << 4);
+		state.attenuation.log += state.adsr_attenuation_ + (overrides->attenuation << 4);
 	} else {
 		// Overrides here represent per-channel volume on an OPLL. The bits are defined to represent
 		// attenuations of 24db to 0.75db.
-		state.attenuation.logsin += (state.adsr_attenuation_ << 3) + (attenuation_ << 5);
+		state.attenuation.log += (state.adsr_attenuation_ << 3) + (attenuation_ << 5);
 	}
 }

Components/OPL2/Implementation/Operator.hpp

@@ -10,7 +10,7 @@
 #define Operator_hpp
 
 #include <cstdint>
-#include "Tables.h"
+#include "Tables.hpp"
 
 namespace Yamaha {
 namespace OPL {
@@ -24,7 +24,7 @@ struct OperatorState {
 		int level();
 
 	private:
-		LogSin attenuation;
+		LogSign attenuation;
 		int raw_phase_ = 0;
 
 		enum class ADSRPhase {

Components/OPL2/Implementation/Tables.hpp

@@ -1,13 +1,13 @@
 //
-//  Tables.h
+//  Tables.hpp
 //  Clock Signal
 //
 //  Created by Thomas Harte on 15/04/2020.
 //  Copyright © 2020 Thomas Harte. All rights reserved.
 //
 
-#ifndef Tables_h
+#ifndef Tables_hpp
-#define Tables_h
+#define Tables_hpp
 
 namespace Yamaha {
 namespace OPL {
@@ -21,14 +21,14 @@ namespace OPL {
 */
 
 
-struct LogSin {
+struct LogSign {
-	int logsin;
+	int log;
 	int sign;
 };
 /*!
 	@returns Negative log sin of x, assuming a 1024-unit circle.
 */
-constexpr LogSin negative_log_sin(int x) {
+constexpr LogSign negative_log_sin(int x) {
 	/// Defines the first quadrant of 1024-unit negative log to the base two of  sine (that conveniently misses sin(0)).
 	///
 	/// Expected branchless usage for a full 1024 unit output:
@@ -77,7 +77,7 @@ constexpr LogSin negative_log_sin(int x) {
 	constexpr int16_t mask[] = { 0, 255 };
 
 	return {
-		.logsin = log_sin[x & 255] ^ mask[(x >> 8) & 1],
+		.log = log_sin[x & 255] ^ mask[(x >> 8) & 1],
 		.sign = sign[(x >> 9) & 1]
 	};
 }
@@ -85,7 +85,7 @@ constexpr LogSin negative_log_sin(int x) {
 /*!
 	@returns 2 ^ -x/256 in 0.10 fixed-point form.
 */
-constexpr int power_two(int x) {
+constexpr int power_two(LogSign ls) {
 	/// A derivative of the exponent table in a real OPL2; mapped_exp[x] = (source[c ^ 0xff] << 1) | 0x800.
 	///
 	/// The ahead-of-time transformation represents fixed work the OPL2 does when reading its table
@@ -102,7 +102,7 @@ constexpr int power_two(int x) {
 	/// be achieved more easily. Specifically, to convert a logarithmic attenuation to a linear one, just perform:
 	///
 	///	result = mapped_exp[x & 0xff] >> (x >> 8)
-	constexpr int mapped_exp[] = {
+	constexpr int16_t mapped_exp[] = {
 		4084,	4074,	4062,	4052,	4040,	4030,	4020,	4008,
 		3998,	3986,	3976,	3966,	3954,	3944,	3932,	3922,
 		3912,	3902,	3890,	3880,	3870,	3860,	3848,	3838,
@@ -137,7 +137,7 @@ constexpr int power_two(int x) {
 		2088,	2082,	2076,	2070,	2064,	2060,	2054,	2048,
 	};
 
-	return mapped_exp[x & 0xff] >> (x >> 8);
+	return (mapped_exp[ls.log & 0xff] >> (ls.log >> 8)) * ls.sign;
 }
 
 /*
@@ -195,4 +195,4 @@ constexpr uint8_t percussion_patch_set[] = {
 }
 }
 
-#endif /* Tables_h */
+#endif /* Tables_hpp */

Components/OPL2/OPL2.cpp

@@ -11,8 +11,6 @@
 #include <cassert>
 #include <cmath>
 
-#include "Implementation/Tables.h"
-
 using namespace Yamaha::OPL;
 
 template <typename Child>

OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj

@@ -1660,7 +1660,7 @@
 		4BC0CB312447EC7C00A79DBB /* Operator.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Operator.hpp; sourceTree = "<group>"; };
 		4BC0CB352447EC9A00A79DBB /* Channel.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = Channel.cpp; sourceTree = "<group>"; };
 		4BC0CB362447EC9A00A79DBB /* Channel.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Channel.hpp; sourceTree = "<group>"; };
-		4BC0CB3A2447ECAE00A79DBB /* Tables.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = Tables.h; sourceTree = "<group>"; };
+		4BC0CB3A2447ECAE00A79DBB /* Tables.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Tables.hpp; sourceTree = "<group>"; };
 		4BC1316D2346DE5000E4FF3D /* StaticAnalyser.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = StaticAnalyser.hpp; sourceTree = "<group>"; };
 		4BC1316E2346DE5000E4FF3D /* Target.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Target.hpp; sourceTree = "<group>"; };
 		4BC1316F2346DE5000E4FF3D /* StaticAnalyser.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = StaticAnalyser.cpp; sourceTree = "<group>"; };
@@ -3514,7 +3514,7 @@
 				4BC0CB312447EC7C00A79DBB /* Operator.hpp */,
 				4BC0CB352447EC9A00A79DBB /* Channel.cpp */,
 				4BC0CB362447EC9A00A79DBB /* Channel.hpp */,
-				4BC0CB3A2447ECAE00A79DBB /* Tables.h */,
+				4BC0CB3A2447ECAE00A79DBB /* Tables.hpp */,
 			);
 			path = Implementation;
 			sourceTree = "<group>";