From 3679e1e8d6049a150b7f55a71808df7b2aba4bd7 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Mon, 30 Jan 2017 15:02:19 -0800
Subject: [PATCH] DS IPC: Implement IPC read

---
 include/mgba/internal/ds/io.h |  2 ++
 src/ds/io.c                   | 20 ++++++++++++++++++++
 src/ds/ipc.c                  | 20 ++++++++++++++++++++
 src/ds/memory.c               |  4 ++--
 4 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/include/mgba/internal/ds/io.h b/include/mgba/internal/ds/io.h
index 047cfb603..c2be86de0 100644
--- a/include/mgba/internal/ds/io.h
+++ b/include/mgba/internal/ds/io.h
@@ -282,12 +282,14 @@ void DS7IOWrite(struct DS* ds, uint32_t address, uint16_t value);
 void DS7IOWrite8(struct DS* ds, uint32_t address, uint8_t value);
 void DS7IOWrite32(struct DS* ds, uint32_t address, uint32_t value);
 uint16_t DS7IORead(struct DS* ds, uint32_t address);
+uint32_t DS7IORead32(struct DS* ds, uint32_t address);
 
 void DS9IOInit(struct DS* ds);
 void DS9IOWrite(struct DS* ds, uint32_t address, uint16_t value);
 void DS9IOWrite8(struct DS* ds, uint32_t address, uint8_t value);
 void DS9IOWrite32(struct DS* ds, uint32_t address, uint32_t value);
 uint16_t DS9IORead(struct DS* ds, uint32_t address);
+uint32_t DS9IORead32(struct DS* ds, uint32_t address);
 
 CXX_GUARD_END
 
diff --git a/src/ds/io.c b/src/ds/io.c
index dc7c26933..4d75ae2b0 100644
--- a/src/ds/io.c
+++ b/src/ds/io.c
@@ -207,6 +207,7 @@ uint16_t DS7IORead(struct DS* ds, uint32_t address) {
 	case DS_REG_TM2CNT_HI:
 	case DS_REG_TM3CNT_HI:
 	case DS_REG_IPCSYNC:
+	case DS_REG_IPCFIFOCNT:
 	case DS_REG_IME:
 	case DS_REG_IE_LO:
 	case DS_REG_IE_HI:
@@ -223,6 +224,15 @@ uint16_t DS7IORead(struct DS* ds, uint32_t address) {
 	return 0;
 }
 
+uint32_t DS7IORead32(struct DS* ds, uint32_t address) {
+	switch (address) {
+	case DS_REG_IPCFIFORECV_LO:
+		return DSIPCReadFIFO(&ds->ds7);
+	default:
+		return DS7IORead(ds, address & 0x00FFFFFC) | (DS7IORead(ds, (address & 0x00FFFFFC) | 2) << 16);
+	}
+}
+
 void DS9IOInit(struct DS* ds) {
 	memset(ds->memory.io9, 0, sizeof(ds->memory.io9));
 }
@@ -328,6 +338,7 @@ uint16_t DS9IORead(struct DS* ds, uint32_t address) {
 	case DS_REG_TM2CNT_HI:
 	case DS_REG_TM3CNT_HI:
 	case DS_REG_IPCSYNC:
+	case DS_REG_IPCFIFOCNT:
 	case DS_REG_IME:
 	case DS_REG_IE_LO:
 	case DS_REG_IE_HI:
@@ -343,3 +354,12 @@ uint16_t DS9IORead(struct DS* ds, uint32_t address) {
 	}
 	return 0;
 }
+
+uint32_t DS9IORead32(struct DS* ds, uint32_t address) {
+	switch (address) {
+	case DS_REG_IPCFIFORECV_LO:
+		return DSIPCReadFIFO(&ds->ds9);
+	default:
+		return DS9IORead(ds, address & 0x00FFFFFC) | (DS9IORead(ds, (address & 0x00FFFFFC) | 2) << 16);
+	}
+}
diff --git a/src/ds/ipc.c b/src/ds/ipc.c
index 570fd4dc3..2ba387dda 100644
--- a/src/ds/ipc.c
+++ b/src/ds/ipc.c
@@ -48,3 +48,23 @@ void DSIPCWriteFIFO(struct DSCommon* dscore, int32_t value) {
 		dscore->ipc->memory.io[DS_REG_IPCFIFOCNT >> 1] = DSIPCFIFOCNTFillRecvFull(dscore->ipc->memory.io[DS_REG_IPCFIFOCNT >> 1]);
 	}
 }
+
+int32_t DSIPCReadFIFO(struct DSCommon* dscore) {
+	if (!DSIPCFIFOCNTIsEnable(dscore->memory.io[DS_REG_IPCFIFOCNT >> 1])) {
+		return 0;
+	}
+	int32_t value = ((int32_t*) dscore->ipc->memory.io)[DS_REG_IPCFIFOSEND_LO >> 2]; // TODO: actual last value
+	CircleBufferRead32(&dscore->fifo, &value);
+	size_t fullness = CircleBufferSize(&dscore->fifo);
+	dscore->memory.io[DS_REG_IPCFIFOCNT >> 1] = DSIPCFIFOCNTClearRecvFull(dscore->memory.io[DS_REG_IPCFIFOCNT >> 1]);
+	dscore->ipc->memory.io[DS_REG_IPCFIFOCNT >> 1] = DSIPCFIFOCNTClearSendFull(dscore->ipc->memory.io[DS_REG_IPCFIFOCNT >> 1]);
+	if (fullness == 0) {
+		dscore->memory.io[DS_REG_IPCFIFOCNT >> 1] = DSIPCFIFOCNTFillRecvEmpty(dscore->memory.io[DS_REG_IPCFIFOCNT >> 1]);
+		dscore->ipc->memory.io[DS_REG_IPCFIFOCNT >> 1] = DSIPCFIFOCNTFillSendEmpty(dscore->ipc->memory.io[DS_REG_IPCFIFOCNT >> 1]);
+		if (DSIPCFIFOCNTIsSendIRQ(dscore->ipc->memory.io[DS_REG_IPCFIFOCNT >> 1])) {
+			// TODO: Adaptive time slicing?
+			DSRaiseIRQ(dscore->ipc->cpu, dscore->ipc->memory.io, DS_IRQ_IPC_NOT_EMPTY);
+		}
+	}
+	return value;
+}
diff --git a/src/ds/memory.c b/src/ds/memory.c
index c778391a3..df5e0b246 100644
--- a/src/ds/memory.c
+++ b/src/ds/memory.c
@@ -237,7 +237,7 @@ uint32_t DS7Load32(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
 		mLOG(DS_MEM, STUB, "Unimplemented DS7 Load32: %08X", address);
 		break;
 	case DS_REGION_IO:
-		value = DS7IORead(ds, address & 0x00FFFFFC) | (DS7IORead(ds, (address & 0x00FFFFFC) | 2) << 16);
+		value = DS7IORead32(ds, address & 0x00FFFFFC);
 		break;
 	default:
 		mLOG(DS_MEM, STUB, "Unimplemented DS7 Load32: %08X", address);
@@ -681,7 +681,7 @@ uint32_t DS9Load32(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
 		mLOG(DS_MEM, STUB, "Unimplemented DS9 Load32: %08X", address);
 		break;
 	case DS_REGION_IO:
-		value = DS9IORead(ds, address & 0x00FFFFFC) | (DS9IORead(ds, (address & 0x00FFFFFC) | 2) << 16);
+		value = DS9IORead32(ds, address & 0x00FFFFFC);
 		break;
 	case DS9_REGION_BIOS:
 		// TODO: Fix undersized BIOS