From 1b0b540de6743d306e1e53583b1ed24215a25334 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 21 May 2024 23:24:06 -0700
Subject: [PATCH] GBA SIO: Move cycle estimation values into core

---
 include/mgba/internal/gba/sio.h |  4 ++--
 src/gba/extra/battlechip.c      |  7 +------
 src/gba/sio.c                   | 27 ++++++++++++++++++++++++++-
 src/gba/sio/lockstep.c          | 14 +++-----------
 4 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/include/mgba/internal/gba/sio.h b/include/mgba/internal/gba/sio.h
index a546017dc..2576dfffe 100644
--- a/include/mgba/internal/gba/sio.h
+++ b/include/mgba/internal/gba/sio.h
@@ -16,8 +16,6 @@ CXX_GUARD_START
 
 #define MAX_GBAS 4
 
-extern const int GBASIOCyclesPerTransfer[4][MAX_GBAS];
-
 mLOG_DECLARE_CATEGORY(GBA_SIO);
 
 enum {
@@ -85,6 +83,8 @@ void GBASIOWriteRCNT(struct GBASIO* sio, uint16_t value);
 void GBASIOWriteSIOCNT(struct GBASIO* sio, uint16_t value);
 uint16_t GBASIOWriteRegister(struct GBASIO* sio, uint32_t address, uint16_t value);
 
+int32_t GBASIOTransferCycles(struct GBASIO* sio);
+
 void GBASIOMultiplayerFinishTransfer(struct GBASIO* sio, uint16_t data[4], uint32_t cyclesLate);
 
 int GBASIOJOYSendCommand(struct GBASIODriver* sio, enum GBASIOJOYCommand command, uint8_t* data);
diff --git a/src/gba/extra/battlechip.c b/src/gba/extra/battlechip.c
index 12750f67b..3314ff02c 100644
--- a/src/gba/extra/battlechip.c
+++ b/src/gba/extra/battlechip.c
@@ -105,12 +105,7 @@ static int GBASIOBattlechipGateConnectedDevices(struct GBASIODriver* driver) {
 }
 
 void _battlechipTransfer(struct GBASIOBattlechipGate* gate) {
-	int32_t cycles;
-	if (gate->d.p->mode == GBA_SIO_NORMAL_32) {
-		cycles = GBA_ARM7TDMI_FREQUENCY / 0x40000;
-	} else {
-		cycles = GBASIOCyclesPerTransfer[GBASIOMultiplayerGetBaud(gate->d.p->siocnt)][1];
-	}
+	int32_t cycles = GBASIOTransferCycles(gate->d.p);
 	mTimingDeschedule(&gate->d.p->p->timing, &gate->event);
 	mTimingSchedule(&gate->d.p->p->timing, &gate->event, cycles);
 }
diff --git a/src/gba/sio.c b/src/gba/sio.c
index cdccf1ea3..76d2ea144 100644
--- a/src/gba/sio.c
+++ b/src/gba/sio.c
@@ -11,7 +11,7 @@
 
 mLOG_DEFINE_CATEGORY(GBA_SIO, "GBA Serial I/O", "gba.sio");
 
-const int GBASIOCyclesPerTransfer[4][MAX_GBAS] = {
+static const int GBASIOCyclesPerTransfer[4][MAX_GBAS] = {
 	{ 31976, 63427, 94884, 125829 },
 	{ 8378, 16241, 24104, 31457 },
 	{ 5750, 10998, 16241, 20972 },
@@ -318,6 +318,31 @@ uint16_t GBASIOWriteRegister(struct GBASIO* sio, uint32_t address, uint16_t valu
 	return value;
 }
 
+int32_t GBASIOTransferCycles(struct GBASIO* sio) {
+	int connected = 0;
+	if (sio->activeDriver) {
+		connected = sio->activeDriver->connectedDevices(sio->activeDriver);
+	}
+
+	if (connected < 0 || connected >= MAX_GBAS) {
+		mLOG(GBA_SIO, ERROR, "SIO driver returned invalid device count %i", connected);
+		return 0;
+	}
+
+	switch (sio->mode) {
+	case GBA_SIO_MULTI:
+		return GBASIOCyclesPerTransfer[GBASIOMultiplayerGetBaud(sio->siocnt)][connected];
+	case GBA_SIO_NORMAL_8:
+		return 8 * GBA_ARM7TDMI_FREQUENCY / ((GBASIONormalIsInternalSc(sio->siocnt) ? 2048 : 256) * 1024);
+	case GBA_SIO_NORMAL_32:
+		return 32 * GBA_ARM7TDMI_FREQUENCY / ((GBASIONormalIsInternalSc(sio->siocnt) ? 2048 : 256) * 1024);
+	default:
+		mLOG(GBA_SIO, STUB, "No cycle count implemented for mode %s", _modeName(sio->mode));
+		break;
+	}
+	return 0;
+}
+
 void GBASIOMultiplayerFinishTransfer(struct GBASIO* sio, uint16_t data[4], uint32_t cyclesLate) {
 	int id = 0;
 	if (sio->activeDriver && sio->activeDriver->deviceId) {
diff --git a/src/gba/sio/lockstep.c b/src/gba/sio/lockstep.c
index b7f5752b4..08c586ae5 100644
--- a/src/gba/sio/lockstep.c
+++ b/src/gba/sio/lockstep.c
@@ -250,7 +250,7 @@ static uint16_t GBASIOLockstepNodeMultiWriteRegister(struct GBASIODriver* driver
 			if (!node->id && attached > 1 && GBASIOMultiplayerIsReady(node->d.p->siocnt)) {
 				mLOG(GBA_SIO, DEBUG, "Lockstep %i: Transfer initiated", node->id);
 				ATOMIC_STORE(node->p->d.transferActive, TRANSFER_STARTING);
-				ATOMIC_STORE(node->p->d.transferCycles, GBASIOCyclesPerTransfer[GBASIOMultiplayerGetBaud(node->d.p->siocnt)][node->p->d.attached - 1]);
+				ATOMIC_STORE(node->p->d.transferCycles, GBASIOTransferCycles(node->d.p));
 
 				if (mTimingIsScheduled(&driver->p->p->timing, &node->event)) {
 					node->eventDiff -= node->event.when - mTimingCurrentTime(&driver->p->p->timing);
@@ -502,7 +502,7 @@ static void _GBASIOLockstepNodeProcessEvents(struct mTiming* timing, void* user,
 	if (node->p->d.attached < 2) {
 		switch (node->mode) {
 		case GBA_SIO_MULTI:
-			cycles = GBASIOCyclesPerTransfer[GBASIOMultiplayerGetBaud(node->d.p->siocnt)][0];
+			cycles = GBASIOTransferCycles(node->d.p);
 			break;
 		case GBA_SIO_NORMAL_8:
 		case GBA_SIO_NORMAL_32:
@@ -568,15 +568,7 @@ static uint16_t GBASIOLockstepNodeNormalWriteRegister(struct GBASIODriver* drive
 		if ((value & 0x0081) == 0x0081) {
 			if (!node->id) {
 				// Frequency
-				int32_t cycles;
-				if (value & 2) {
-					cycles = 8 * 8;
-				} else {
-					cycles = 64 * 8;
-				}
-				if (value & 0x1000) {
-					cycles *= 4;
-				}
+				int32_t cycles = GBASIOTransferCycles(node->d.p);
 
 				if (transferActive == TRANSFER_IDLE) {
 					mLOG(GBA_SIO, DEBUG, "Lockstep %i: Transfer initiated", node->id);