From 9a264c7c06fb0edf81aa447e047d5c79c04ed5cc Mon Sep 17 00:00:00 2001
From: "Adrian.Conlon" <adrian.conlon@gmail.com>
Date: Sat, 22 Jul 2017 10:23:13 +0100
Subject: [PATCH] Bring the LR35902 and i8080 increment/decrement
 implementations in line with the Z80.

Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
---
 Intel8080/inc/Intel8080.h | 48 ++++++++++++++++++---------------------
 LR35902/inc/LR35902.h     |  4 ++--
 LR35902/src/LR35902.cpp   | 16 ++++++-------
 3 files changed, 32 insertions(+), 36 deletions(-)

diff --git a/Intel8080/inc/Intel8080.h b/Intel8080/inc/Intel8080.h
index 14ca744..5a78849 100644
--- a/Intel8080/inc/Intel8080.h
+++ b/Intel8080/inc/Intel8080.h
@@ -90,14 +90,14 @@ namespace EightBit {
 			clearFlag(f, AC, calculateHalfCarrySub(before, value, calculation));
 		}
 
-		static void postIncrement(uint8_t& f, uint8_t value) {
-			adjustSZP<Intel8080>(f, value);
-			clearFlag(f, AC, lowNibble(value));
+		static void increment(uint8_t& f, uint8_t& operand) {
+			adjustSZP<Intel8080>(f, ++operand);
+			clearFlag(f, AC, lowNibble(operand));
 		}
 
-		static void postDecrement(uint8_t& f, uint8_t value) {
-			adjustSZP<Intel8080>(f, value);
-			setFlag(f, AC, lowNibble(value) != Mask4);
+		static void decrement(uint8_t& f, uint8_t& operand) {
+			adjustSZP<Intel8080>(f, --operand);
+			setFlag(f, AC, lowNibble(operand) != Mask4);
 		}
 
 		static Instruction INS(instruction_t method, AddressingMode mode, std::string disassembly, int cycles);
@@ -420,34 +420,30 @@ namespace EightBit {
 
 		// increment and decrement
 
-		void inr_a() { postIncrement(F(), ++A()); }
-		void inr_b() { postIncrement(F(), ++B()); }
-		void inr_c() { postIncrement(F(), ++C()); }
-		void inr_d() { postIncrement(F(), ++D()); }
-		void inr_e() { postIncrement(F(), ++E()); }
-		void inr_h() { postIncrement(F(), ++H()); }
-		void inr_l() { postIncrement(F(), ++L()); }
+		void inr_a() { increment(F(), A()); }
+		void inr_b() { increment(F(), B()); }
+		void inr_c() { increment(F(), C()); }
+		void inr_d() { increment(F(), D()); }
+		void inr_e() { increment(F(), E()); }
+		void inr_h() { increment(F(), H()); }
+		void inr_l() { increment(F(), L()); }
 
 		void inr_m() {
 			m_memory.ADDRESS() = HL();
-			auto value = m_memory.reference();
-			postIncrement(F(), ++value);
-			m_memory.reference() = value;
+			increment(F(), m_memory.reference());
 		}
 
-		void dcr_a() { postDecrement(F(), --A()); }
-		void dcr_b() { postDecrement(F(), --B()); }
-		void dcr_c() { postDecrement(F(), --C()); }
-		void dcr_d() { postDecrement(F(), --D()); }
-		void dcr_e() { postDecrement(F(), --E()); }
-		void dcr_h() { postDecrement(F(), --H()); }
-		void dcr_l() { postDecrement(F(), --L()); }
+		void dcr_a() { decrement(F(), A()); }
+		void dcr_b() { decrement(F(), B()); }
+		void dcr_c() { decrement(F(), C()); }
+		void dcr_d() { decrement(F(), D()); }
+		void dcr_e() { decrement(F(), E()); }
+		void dcr_h() { decrement(F(), H()); }
+		void dcr_l() { decrement(F(), L()); }
 
 		void dcr_m() {
 			m_memory.ADDRESS() = HL();
-			auto value = m_memory.reference();
-			postDecrement(F(), --value);
-			m_memory.reference() = value;
+			decrement(F(), m_memory.reference());
 		}
 
 		void inx_b() { ++BC().word; }
diff --git a/LR35902/inc/LR35902.h b/LR35902/inc/LR35902.h
index d08640c..9352131 100644
--- a/LR35902/inc/LR35902.h
+++ b/LR35902/inc/LR35902.h
@@ -162,8 +162,8 @@ namespace EightBit {
 		void executeCB(int x, int y, int z, int p, int q);
 		void executeOther(int x, int y, int z, int p, int q);
 
-		static void postIncrement(uint8_t& f, uint8_t value);
-		static void postDecrement(uint8_t& f, uint8_t value);
+		static void increment(uint8_t& f, uint8_t& operand);
+		static void decrement(uint8_t& f, uint8_t& operand);
 
 		void reti();
 
diff --git a/LR35902/src/LR35902.cpp b/LR35902/src/LR35902.cpp
index 2222787..c3fc23c 100644
--- a/LR35902/src/LR35902.cpp
+++ b/LR35902/src/LR35902.cpp
@@ -51,16 +51,16 @@ int EightBit::LR35902::interrupt(uint8_t value) {
 
 #pragma region Flag manipulation helpers
 
-void EightBit::LR35902::postIncrement(uint8_t& f, uint8_t value) {
-	adjustZero<LR35902>(f, value);
+void EightBit::LR35902::increment(uint8_t& f, uint8_t& operand) {
 	clearFlag(f, NF);
-	clearFlag(f, HC, lowNibble(value));
+	adjustZero<LR35902>(f, ++operand);
+	clearFlag(f, HC, lowNibble(operand));
 }
 
-void EightBit::LR35902::postDecrement(uint8_t& f, uint8_t value) {
-	adjustZero<LR35902>(f, value);
+void EightBit::LR35902::decrement(uint8_t& f, uint8_t& operand) {
 	setFlag(f, NF);
-	clearFlag(f, HC, lowNibble(value + 1));
+	clearFlag(f, HC, lowNibble(operand));
+	adjustZero<LR35902>(f, --operand);
 }
 
 #pragma endregion Flag manipulation helpers
@@ -573,7 +573,7 @@ void EightBit::LR35902::executeOther(int x, int y, int z, int p, int q) {
 			cycles += 2;
 			break;
 		case 4:	// 8-bit INC
-			postIncrement(f, ++R(y, a));	// INC r
+			increment(f, R(y, a));	// INC r
 			cycles++;
 			if (y == 6) {
 				m_bus.fireWriteBusEvent();
@@ -581,7 +581,7 @@ void EightBit::LR35902::executeOther(int x, int y, int z, int p, int q) {
 			}
 			break;
 		case 5:	// 8-bit DEC
-			postDecrement(f, --R(y, a));	// DEC r
+			decrement(f, R(y, a));	// DEC r
 			cycles++;
 			if (y == 6) {
 				m_bus.fireWriteBusEvent();