From 3b74b61862da06b71d6cb256754f48feec409f7f Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Sun, 3 Nov 2013 23:25:57 -0800
Subject: [PATCH] Move halting code out from below the ARM emulator

---
 src/gba/gba.c | 85 +++++++++++++++++++++++----------------------------
 src/gba/gba.h |  4 +--
 2 files changed, 40 insertions(+), 49 deletions(-)

diff --git a/src/gba/gba.c b/src/gba/gba.c
index 0bc5af8f4..f7ddfa25b 100644
--- a/src/gba/gba.c
+++ b/src/gba/gba.c
@@ -152,37 +152,47 @@ void GBABoardReset(struct ARMBoard* board) {
 
 static void GBAProcessEvents(struct ARMBoard* board) {
 	struct GBABoard* gbaBoard = (struct GBABoard*) board;
-	int32_t cycles = board->cpu->cycles;
-	int32_t nextEvent = INT_MAX;
-	int32_t testEvent;
+	do {
+		int32_t cycles = board->cpu->cycles;
+		int32_t nextEvent = INT_MAX;
+		int32_t testEvent;
 
-	if (gbaBoard->p->springIRQ) {
-		ARMRaiseIRQ(&gbaBoard->p->cpu);
-		gbaBoard->p->springIRQ = 0;
-	}
+		if (gbaBoard->p->springIRQ) {
+			ARMRaiseIRQ(&gbaBoard->p->cpu);
+			gbaBoard->p->springIRQ = 0;
+		}
 
-	testEvent = GBAVideoProcessEvents(&gbaBoard->p->video, cycles);
-	if (testEvent < nextEvent) {
-		nextEvent = testEvent;
-	}
+		testEvent = GBAVideoProcessEvents(&gbaBoard->p->video, cycles);
+		if (testEvent < nextEvent) {
+			nextEvent = testEvent;
+		}
 
-	testEvent = GBAAudioProcessEvents(&gbaBoard->p->audio, cycles);
-	if (testEvent < nextEvent) {
-		nextEvent = testEvent;
-	}
+		testEvent = GBAAudioProcessEvents(&gbaBoard->p->audio, cycles);
+		if (testEvent < nextEvent) {
+			nextEvent = testEvent;
+		}
 
-	testEvent = GBAMemoryProcessEvents(&gbaBoard->p->memory, cycles);
-	if (testEvent < nextEvent) {
-		nextEvent = testEvent;
-	}
+		testEvent = GBAMemoryProcessEvents(&gbaBoard->p->memory, cycles);
+		if (testEvent < nextEvent) {
+			nextEvent = testEvent;
+		}
 
-	testEvent = GBATimersProcessEvents(gbaBoard->p, cycles);
-	if (testEvent < nextEvent) {
-		nextEvent = testEvent;
-	}
+		testEvent = GBATimersProcessEvents(gbaBoard->p, cycles);
+		if (testEvent < nextEvent) {
+			nextEvent = testEvent;
+		}
 
-	board->cpu->cycles = 0;
-	board->cpu->nextEvent = nextEvent;
+		board->cpu->cycles = 0;
+		board->cpu->nextEvent = nextEvent;
+
+		if (gbaBoard->p->halted) {
+			gbaBoard->p->halted = !(gbaBoard->p->memory.io[REG_IF >> 1] & gbaBoard->p->memory.io[REG_IE >> 1]);
+			board->cpu->cycles = nextEvent;
+			if (nextEvent == INT_MAX) {
+				break;
+			}
+		}
+	} while (gbaBoard->p->halted);
 }
 
 static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
@@ -456,28 +466,9 @@ void GBATestIRQ(struct ARMBoard* board) {
 	}
 }
 
-int GBAWaitForIRQ(struct GBA* gba) {
-	int irqs = gba->memory.io[REG_IF >> 1];
-	int newIRQs = 0;
-	gba->memory.io[REG_IF >> 1] = 0;
-	while (1) {
-		if (gba->cpu.nextEvent == INT_MAX) {
-			break;
-		} else {
-			gba->cpu.cycles = gba->cpu.nextEvent;
-			GBAProcessEvents(&gba->board.d);
-			if (gba->memory.io[REG_IF >> 1]) {
-				newIRQs = gba->memory.io[REG_IF >> 1];
-				break;
-			}
-		}
-	}
-	gba->memory.io[REG_IF >> 1] = newIRQs | irqs;
-	return newIRQs;
-}
-
-int GBAHalt(struct GBA* gba) {
-	return GBAWaitForIRQ(gba);
+void GBAHalt(struct GBA* gba) {
+	gba->cpu.cycles = gba->cpu.nextEvent;
+	gba->halted = 1;
 }
 
 void GBALog(struct GBA* gba, enum GBALogLevel level, const char* format, ...) {
diff --git a/src/gba/gba.h b/src/gba/gba.h
index bc3561be5..100f01766 100644
--- a/src/gba/gba.h
+++ b/src/gba/gba.h
@@ -85,6 +85,7 @@ struct GBA {
 		unsigned enable : 1;
 	} timers[4];
 
+	int halted;
 	int springIRQ;
 	int* keySource;
 	struct GBARotationSource* rotationSource;
@@ -127,8 +128,7 @@ void GBAWriteIE(struct GBA* gba, uint16_t value);
 void GBAWriteIME(struct GBA* gba, uint16_t value);
 void GBARaiseIRQ(struct GBA* gba, enum GBAIRQ irq);
 void GBATestIRQ(struct ARMBoard* board);
-int GBAWaitForIRQ(struct GBA* gba);
-int GBAHalt(struct GBA* gba);
+void GBAHalt(struct GBA* gba);
 
 void GBAAttachDebugger(struct GBA* gba, struct ARMDebugger* debugger);