From 7e5de27f43a680da74c4efc3b108e9cf3c4b2652 Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Wed, 10 Apr 2013 23:34:50 -0700
Subject: [PATCH] Add ability to run Thumb code

---
 src/arm.c       | 7 +++++++
 src/arm.h       | 2 ++
 src/isa-thumb.c | 9 +++++++++
 src/main.c      | 2 +-
 4 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/arm.c b/src/arm.c
index 2caf04cdb..f840dc7fb 100644
--- a/src/arm.c
+++ b/src/arm.c
@@ -106,3 +106,10 @@ void ARMReset(struct ARMCore* cpu) {
 	cpu->board->reset(cpu->board);
 }
 
+void ARMRun(struct ARMCore* cpu) {
+	if (cpu->executionMode) {
+		ThumbStep(cpu);
+	} else {
+		ARMStep(cpu);
+	}
+}
diff --git a/src/arm.h b/src/arm.h
index 6b9b5e25a..fa0046f8e 100644
--- a/src/arm.h
+++ b/src/arm.h
@@ -116,4 +116,6 @@ void ARMAssociateBoard(struct ARMCore* cpu, struct ARMBoard* board);
 void ARMReset(struct ARMCore* cpu);
 void ARMSetPrivilegeMode(struct ARMCore*, enum PrivilegeMode);
 
+void ARMRun(struct ARMCore* cpu);
+
 #endif
diff --git a/src/isa-thumb.c b/src/isa-thumb.c
index 70611e465..c9c7b5bb7 100644
--- a/src/isa-thumb.c
+++ b/src/isa-thumb.c
@@ -4,6 +4,15 @@
 
 static const ThumbInstruction _thumbTable[0x400];
 
+void ThumbStep(struct ARMCore* cpu) {
+	uint32_t address = cpu->gprs[ARM_PC];
+	cpu->gprs[ARM_PC] = address + WORD_SIZE_THUMB;
+	address -= WORD_SIZE_THUMB;
+	uint16_t opcode = ((uint16_t*) cpu->memory->activeRegion)[(address & cpu->memory->activeMask) >> 1];
+	ThumbInstruction instruction = _thumbTable[opcode >> 6];
+	instruction(cpu, opcode);
+}
+
 // Instruction definitions
 // Beware pre-processor insanity
 
diff --git a/src/main.c b/src/main.c
index dc5445e2d..c2ed2d217 100644
--- a/src/main.c
+++ b/src/main.c
@@ -15,7 +15,7 @@ int main(int argc, char** argv) {
 	gba.memory.d.setActiveRegion(&gba.memory.d, gba.cpu.gprs[ARM_PC]);
 	int i;
 	for (i = 0; i < 1024 * 1024 * 16; ++i) {
-		ARMStep(&gba.cpu);
+		ARMRun(&gba.cpu);
 	}
 	GBADeinit(&gba);
 	close(fd);