SM83: Simplify register pair access on big endian

CHANGES

@@ -49,6 +49,7 @@ Other fixes:
  - Qt: Fix Italian RTC translation (fixes mgba.io/i/1798)
  - Qt: Add missing option for Wisdom Tree in overrides list
  - Util: Fix crash if PNG header fails to write
+ - SM83: Simplify register pair access on big endian
 Misc:
  - Debugger: Keep track of global cycle count
  - FFmpeg: Add looping option for GIF/APNG

include/mgba/internal/sm83/sm83.h

@@ -74,37 +74,42 @@ struct SM83InterruptHandler {
 	void (*hitIllegal)(struct SM83Core* cpu);
 };
 
+#ifdef __BIG_ENDIAN__
+#define SM83_REGISTER_PAIR(HIGH, LOW) union { \
+		struct { \
+			uint8_t HIGH; \
+			uint8_t LOW; \
+		}; \
+		uint16_t HIGH ## LOW; \
+	}
+#else
+#define SM83_REGISTER_PAIR(HIGH, LOW) union { \
+		struct { \
+			uint8_t LOW; \
+			uint8_t HIGH; \
+		}; \
+		uint16_t HIGH ## LOW; \
+	}
+#endif
+
 struct SM83Core {
 #pragma pack(push, 1)
 	union {
 		struct {
+#ifdef __BIG_ENDIAN__
+			uint8_t a;
+			union FlagRegister f;
+#else
 			union FlagRegister f;
 			uint8_t a;
+#endif
 		};
 		uint16_t af;
 	};
 #pragma pack(pop)
-	union {
-		struct {
-			uint8_t c;
-			uint8_t b;
-		};
-		uint16_t bc;
-	};
-	union {
-		struct {
-			uint8_t e;
-			uint8_t d;
-		};
-		uint16_t de;
-	};
-	union {
-		struct {
-			uint8_t l;
-			uint8_t h;
-		};
-		uint16_t hl;
-	};
+	SM83_REGISTER_PAIR(b, c);
+	SM83_REGISTER_PAIR(d, e);
+	SM83_REGISTER_PAIR(h, l);
 	uint16_t sp;
 	uint16_t pc;
 

src/sm83/isa-sm83.c

@@ -9,33 +9,27 @@
 #include <mgba/internal/sm83/sm83.h>
 
 static inline uint16_t SM83ReadHL(struct SM83Core* cpu) {
-	uint16_t hl;
-	LOAD_16LE(hl, 0, &cpu->hl);
-	return hl;
+	return cpu->hl;
 }
 
 static inline void SM83WriteHL(struct SM83Core* cpu, uint16_t hl) {
-	STORE_16LE(hl, 0, &cpu->hl);
+	cpu->hl = hl;
 }
 
 static inline uint16_t SM83ReadBC(struct SM83Core* cpu) {
-	uint16_t bc;
-	LOAD_16LE(bc, 0, &cpu->bc);
-	return bc;
+	return cpu->bc;
 }
 
 static inline void SM83WriteBC(struct SM83Core* cpu, uint16_t bc) {
-	STORE_16LE(bc, 0, &cpu->bc);
+	cpu->bc = bc;
 }
 
 static inline uint16_t SM83ReadDE(struct SM83Core* cpu) {
-	uint16_t de;
-	LOAD_16LE(de, 0, &cpu->de);
-	return de;
+	return cpu->de;
 }
 
 static inline void SM83WriteDE(struct SM83Core* cpu, uint16_t de) {
-	STORE_16LE(de, 0, &cpu->de);
+	cpu->de = de;
 }
 
 #define DEFINE_INSTRUCTION_SM83(NAME, BODY) \
@@ -77,7 +71,7 @@ DEFINE_INSTRUCTION_SM83(JPDelay,
 DEFINE_CONDITIONAL_INSTRUCTION_SM83(JP);
 
 DEFINE_INSTRUCTION_SM83(JPHL,
-	cpu->pc = SM83ReadHL(cpu);
+	cpu->pc = cpu->hl;
 	cpu->memory.setActiveRegion(cpu, cpu->pc);)
 
 DEFINE_INSTRUCTION_SM83(JRFinish,
@@ -226,7 +220,7 @@ DEFINE_CONDITIONAL_ONLY_INSTRUCTION_SM83(RET)
 #define DEFINE_LDHL__INSTRUCTION_SM83(NAME, OPERAND) \
 	DEFINE_INSTRUCTION_SM83(LDHL_ ## NAME, \
 		cpu->bus = OPERAND; \
-		cpu->index = SM83ReadHL(cpu); \
+		cpu->index = cpu->hl; \
 		cpu->executionState = SM83_CORE_MEMORY_STORE; \
 		cpu->instruction = _SM83InstructionNOP;)
 
@@ -244,7 +238,7 @@ DEFINE_CONDITIONAL_ONLY_INSTRUCTION_SM83(RET)
 	DEFINE_ ## NAME ## _INSTRUCTION_SM83(L, cpu->l);
 
 DEFINE_INSTRUCTION_SM83(LDHL_Bus, \
-	cpu->index = SM83ReadHL(cpu); \
+	cpu->index = cpu->hl; \
 	cpu->executionState = SM83_CORE_MEMORY_STORE; \
 	cpu->instruction = _SM83InstructionNOP;)
 
@@ -267,7 +261,7 @@ DEFINE_INSTRUCTION_SM83(LDHL_SP,
 	cpu->instruction = _SM83InstructionLDHL_SPDelay;)
 
 DEFINE_INSTRUCTION_SM83(LDSP_HL,
-	cpu->sp = SM83ReadHL(cpu);
+	cpu->sp = cpu->hl;
 	cpu->executionState = SM83_CORE_STALL;)
 
 #define DEFINE_ALU_INSTRUCTION_SM83_MEM(NAME, REG) \
@@ -378,7 +372,7 @@ DEFINE_INSTRUCTION_SM83(LDBC, \
 	cpu->instruction = _SM83InstructionLDBCDelay;)
 
 DEFINE_INSTRUCTION_SM83(LDBC_A, \
-	cpu->index = SM83ReadBC(cpu); \
+	cpu->index = cpu->bc; \
 	cpu->bus = cpu->a; \
 	cpu->executionState = SM83_CORE_MEMORY_STORE; \
 	cpu->instruction = _SM83InstructionNOP;)
@@ -393,7 +387,7 @@ DEFINE_INSTRUCTION_SM83(LDDE, \
 	cpu->instruction = _SM83InstructionLDDEDelay;)
 
 DEFINE_INSTRUCTION_SM83(LDDE_A, \
-	cpu->index = SM83ReadDE(cpu); \
+	cpu->index = cpu->de; \
 	cpu->bus = cpu->a; \
 	cpu->executionState = SM83_CORE_MEMORY_STORE; \
 	cpu->instruction = _SM83InstructionNOP;)
@@ -419,27 +413,27 @@ DEFINE_INSTRUCTION_SM83(LDSP, \
 	cpu->instruction = _SM83InstructionLDSPDelay;)
 
 DEFINE_INSTRUCTION_SM83(LDIHLA, \
-	cpu->index = SM83ReadHL(cpu); \
+	cpu->index = cpu->hl; \
 	SM83WriteHL(cpu, cpu->index + 1); \
 	cpu->bus = cpu->a; \
 	cpu->executionState = SM83_CORE_MEMORY_STORE; \
 	cpu->instruction = _SM83InstructionNOP;)
 
 DEFINE_INSTRUCTION_SM83(LDDHLA, \
-	cpu->index = SM83ReadHL(cpu); \
+	cpu->index = cpu->hl; \
 	SM83WriteHL(cpu, cpu->index - 1); \
 	cpu->bus = cpu->a; \
 	cpu->executionState = SM83_CORE_MEMORY_STORE; \
 	cpu->instruction = _SM83InstructionNOP;)
 
 DEFINE_INSTRUCTION_SM83(LDA_IHL, \
-	cpu->index = SM83ReadHL(cpu); \
+	cpu->index = cpu->hl; \
 	SM83WriteHL(cpu, cpu->index + 1); \
 	cpu->executionState = SM83_CORE_MEMORY_LOAD; \
 	cpu->instruction = _SM83InstructionLDA_Bus;)
 
 DEFINE_INSTRUCTION_SM83(LDA_DHL, \
-	cpu->index = SM83ReadHL(cpu); \
+	cpu->index = cpu->hl; \
 	SM83WriteHL(cpu, cpu->index - 1); \
 	cpu->executionState = SM83_CORE_MEMORY_LOAD; \
 	cpu->instruction = _SM83InstructionLDA_Bus;)
@@ -587,7 +581,7 @@ DEFINE_INSTRUCTION_SM83(INC_HLDelay,
 	cpu->executionState = SM83_CORE_MEMORY_STORE;)
 
 DEFINE_INSTRUCTION_SM83(INC_HL,
-	cpu->index = SM83ReadHL(cpu);
+	cpu->index = cpu->hl;
 	cpu->instruction = _SM83InstructionINC_HLDelay;
 	cpu->executionState = SM83_CORE_MEMORY_LOAD;)
 
@@ -601,7 +595,7 @@ DEFINE_INSTRUCTION_SM83(DEC_HLDelay,
 	cpu->executionState = SM83_CORE_MEMORY_STORE;)
 
 DEFINE_INSTRUCTION_SM83(DEC_HL,
-	cpu->index = SM83ReadHL(cpu);
+	cpu->index = cpu->hl;
 	cpu->instruction = _SM83InstructionDEC_HLDelay;
 	cpu->executionState = SM83_CORE_MEMORY_LOAD;)
 
@@ -699,7 +693,7 @@ DEFINE_POPPUSH_INSTRUCTION_SM83(AF, A, a, f.packed);
 		cpu->executionState = WB; \
 		cpu->instruction = _SM83InstructionNOP;) \
 	DEFINE_INSTRUCTION_SM83(NAME ## HL, \
-		cpu->index = SM83ReadHL(cpu); \
+		cpu->index = cpu->hl; \
 		cpu->executionState = SM83_CORE_MEMORY_LOAD; \
 		cpu->instruction = _SM83Instruction ## NAME ## HLDelay;) \
 	DEFINE_INSTRUCTION_SM83(NAME ## A, uint8_t reg = cpu->a; BODY; cpu->a = reg)