DS GX: Start implementing FIFO

include/mgba/internal/ds/gx.h

@@ -16,6 +16,20 @@ CXX_GUARD_START
 
 mLOG_DECLARE_CATEGORY(DS_GX);
 
+DECL_BITFIELD(DSRegGXSTAT, uint32_t);
+DECL_BIT(DSRegGXSTAT, TestBusy, 0);
+DECL_BIT(DSRegGXSTAT, BoxTestResult, 1);
+DECL_BITS(DSRegGXSTAT, PVMatrixStackLevel, 8, 5);
+DECL_BIT(DSRegGXSTAT, ProjMatrixStackLevel, 13);
+DECL_BIT(DSRegGXSTAT, MatrixStackBusy, 14);
+DECL_BIT(DSRegGXSTAT, MatrixStackError, 15);
+DECL_BITS(DSRegGXSTAT, FIFOEntries, 16, 9);
+DECL_BIT(DSRegGXSTAT, FIFOFull, 24);
+DECL_BIT(DSRegGXSTAT, FIFOLtHalf, 25);
+DECL_BIT(DSRegGXSTAT, FIFOEmpty, 26);
+DECL_BIT(DSRegGXSTAT, Busy, 27);
+DECL_BITS(DSRegGXSTAT, DoIRQ, 30, 2);
+
 enum DSGXCommand {
 	DS_GX_CMD_NOP = 0,
 	DS_GX_CMD_MTX_MODE = 0x10,
@@ -73,6 +87,8 @@ struct DSGX {
 	struct CircleBuffer fifo;
 
 	struct mTimingEvent fifoEvent;
+
+	bool swapBuffers;
 };
 
 void DSGXInit(struct DSGX*);
@@ -82,6 +98,9 @@ void DSGXReset(struct DSGX*);
 uint16_t DSGXWriteRegister(struct DSGX*, uint32_t address, uint16_t value);
 uint32_t DSGXWriteRegister32(struct DSGX*, uint32_t address, uint32_t value);
 
+void DSGXSwapBuffers(struct DSGX*);
+void DSGXUpdateGXSTAT(struct DSGX*);
+
 CXX_GUARD_END
 
 #endif

src/ds/gx.c

@@ -5,6 +5,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include <mgba/internal/ds/gx.h>
 
+#include <mgba/internal/ds/ds.h>
 #include <mgba/internal/ds/io.h>
 
 mLOG_DEFINE_CATEGORY(DS_GX, "DS GX");
@@ -52,8 +53,49 @@ static const int32_t _gxCommandCycleBase[DS_GX_CMD_MAX] = {
 	[DS_GX_CMD_VEC_TEST] = 10,
 };
 
+static void _fifoRun(struct mTiming* timing, void* context, uint32_t cyclesLate) {
+	struct DSGX* gx = context;
+	uint32_t cycles;
+	while (true) {
+		struct DSGXEntry entry = { 0 };
+		CircleBufferRead8(&gx->fifo, (int8_t*) &entry.command);
+		CircleBufferRead8(&gx->fifo, (int8_t*) &entry.params[0]);
+		CircleBufferRead8(&gx->fifo, (int8_t*) &entry.params[1]);
+		CircleBufferRead8(&gx->fifo, (int8_t*) &entry.params[2]);
+		CircleBufferRead8(&gx->fifo, (int8_t*) &entry.params[3]);
+		cycles = _gxCommandCycleBase[entry.command];
+
+		switch (entry.command) {
+		case DS_GX_CMD_SWAP_BUFFERS:
+			gx->swapBuffers = true;
+			break;
+		default:
+			mLOG(DS_GX, STUB, "Unimplemented GX command %02X:%02X %02X %02X %02X", entry.command, entry.params[0], entry.params[1], entry.params[2], entry.params[3]);
+			break;
+		}
+		if (CircleBufferSize(&gx->fifo)) {
+			if (cycles <= cyclesLate) {
+				cyclesLate -= cycles;
+			} else {
+				break;
+			}
+		} else {
+			cycles = 0;
+			break;
+		}
+	}
+	DSGXUpdateGXSTAT(gx);
+	if (cycles) {
+		mTimingSchedule(&gx->p->ds9.timing, &gx->fifoEvent, cycles);
+	}
+}
+
 void DSGXInit(struct DSGX* gx) {
 	CircleBufferInit(&gx->fifo, sizeof(struct DSGXEntry) * DS_GX_FIFO_SIZE);
+	gx->fifoEvent.name = "DS GX FIFO";
+	gx->fifoEvent.priority = 0xC;
+	gx->fifoEvent.context = gx;
+	gx->fifoEvent.callback = _fifoRun;
 }
 
 void DSGXDeinit(struct DSGX* gx) {
@@ -62,20 +104,86 @@ void DSGXDeinit(struct DSGX* gx) {
 
 void DSGXReset(struct DSGX* gx) {
 	CircleBufferClear(&gx->fifo);
+	gx->swapBuffers = false;
+}
+
+void DSGXUpdateGXSTAT(struct DSGX* gx) {
+	uint32_t value = gx->p->memory.io9[DS9_REG_GXSTAT_HI >> 1] << 16;
+	value = DSRegGXSTATIsDoIRQ(value);
+
+	size_t entries = CircleBufferSize(&gx->fifo) / sizeof(struct DSGXEntry);
+	// XXX
+	if (gx->swapBuffers) {
+		entries++;
+	}
+	value = DSRegGXSTATSetFIFOEntries(value, entries);
+	value = DSRegGXSTATSetFIFOLtHalf(value, entries < (DS_GX_FIFO_SIZE / 2));
+	value = DSRegGXSTATSetFIFOEmpty(value, entries == 0);
+
+	if ((DSRegGXSTATGetDoIRQ(value) == 1 && entries < (DS_GX_FIFO_SIZE / 2)) ||
+		(DSRegGXSTATGetDoIRQ(value) == 2 && entries == 0)) {
+		DSRaiseIRQ(gx->p->ds9.cpu, gx->p->ds9.memory.io, DS_IRQ_GEOM_FIFO);
+	}
+
+	value = DSRegGXSTATSetBusy(value, mTimingIsScheduled(&gx->p->ds9.timing, &gx->fifoEvent) || gx->swapBuffers);
+
+	gx->p->memory.io9[DS9_REG_GXSTAT_HI >> 1] = value >> 16;
+}
+
+static void DSGXWriteFIFO(struct DSGX* gx, struct DSGXEntry entry) {
+	uint32_t cycles = _gxCommandCycleBase[entry.command];
+	if (!cycles) {
+		return;
+	}
+	// TODO: Outstanding parameters
+	if (CircleBufferSize(&gx->fifo) < (DS_GX_FIFO_SIZE * sizeof(entry))) {
+		CircleBufferWrite8(&gx->fifo, entry.command);
+		CircleBufferWrite8(&gx->fifo, entry.params[0]);
+		CircleBufferWrite8(&gx->fifo, entry.params[1]);
+		CircleBufferWrite8(&gx->fifo, entry.params[2]);
+		CircleBufferWrite8(&gx->fifo, entry.params[3]);
+		if (!mTimingIsScheduled(&gx->p->ds9.timing, &gx->fifoEvent)) {
+			mTimingSchedule(&gx->p->ds9.timing, &gx->fifoEvent, 0);
+		}
+	} else {
+		mLOG(DS_GX, STUB, "Unimplemented GX full");
+	}
 }
 
 uint16_t DSGXWriteRegister(struct DSGX* gx, uint32_t address, uint16_t value) {
+	uint16_t oldValue = gx->p->memory.io9[address >> 1];
 	switch (address) {
 	case DS9_REG_DISP3DCNT:
-	case DS9_REG_GXSTAT_LO:
-	case DS9_REG_GXSTAT_HI:
 		mLOG(DS_GX, STUB, "Unimplemented GX write %03X:%04X", address, value);
 		break;
+	case DS9_REG_GXSTAT_LO:
+		value = DSRegGXSTATIsMatrixStackError(value);
+		if (value) {
+			oldValue = DSRegGXSTATClearMatrixStackError(oldValue);
+			oldValue = DSRegGXSTATClearProjMatrixStackLevel(oldValue);
+		}
+		value = oldValue;
+		break;
+	case DS9_REG_GXSTAT_HI:
+		value = DSRegGXSTATIsDoIRQ(value << 16) >> 16;
+		gx->p->memory.io9[address >> 1] = value;
+		DSGXUpdateGXSTAT(gx);
+		value = gx->p->memory.io9[address >> 1];
+		break;
 	default:
 		if (address < DS9_REG_GXFIFO_00) {
 			mLOG(DS_GX, STUB, "Unimplemented GX write %03X:%04X", address, value);
 		} else if (address < DS9_REG_GXSTAT_LO) {
-			mLOG(DS_GX, STUB, "Unimplemented FIFO write %03X:%04X", address, value);
+			struct DSGXEntry entry = {
+				.command = (address & 0x1FC) >> 2,
+				.params = {
+					value,
+					value >> 8,
+				}
+			};
+			if (entry.command < 0x80) {
+				DSGXWriteFIFO(gx, entry);
+			}
 		} else {
 			mLOG(DS_GX, STUB, "Unimplemented GX write %03X:%04X", address, value);
 		}
@@ -87,14 +195,26 @@ uint16_t DSGXWriteRegister(struct DSGX* gx, uint32_t address, uint16_t value) {
 uint32_t DSGXWriteRegister32(struct DSGX* gx, uint32_t address, uint32_t value) {
 	switch (address) {
 	case DS9_REG_DISP3DCNT:
-	case DS9_REG_GXSTAT_LO:
 		mLOG(DS_GX, STUB, "Unimplemented GX write %03X:%04X", address, value);
 		break;
+	case DS9_REG_GXSTAT_LO:
+		value = (value & 0xFFFF0000) | DSGXWriteRegister(gx, DS9_REG_GXSTAT_LO, value);
+		value = (value & 0x0000FFFF) | (DSGXWriteRegister(gx, DS9_REG_GXSTAT_HI, value >> 16) << 16);
+		break;
 	default:
 		if (address < DS9_REG_GXFIFO_00) {
 			mLOG(DS_GX, STUB, "Unimplemented GX write %03X:%04X", address, value);
 		} else if (address < DS9_REG_GXSTAT_LO) {
-			mLOG(DS_GX, STUB, "Unimplemented FIFO write %03X:%04X", address, value);
+			struct DSGXEntry entry = {
+				.command = (address & 0x1FC) >> 2l,
+				.params = {
+					value,
+					value >> 8,
+					value >> 16,
+					value >> 24
+				}
+			};
+			DSGXWriteFIFO(gx, entry);
 		} else {
 			mLOG(DS_GX, STUB, "Unimplemented GX write %03X:%04X", address, value);
 		}
@@ -102,3 +222,14 @@ uint32_t DSGXWriteRegister32(struct DSGX* gx, uint32_t address, uint32_t value)
 	}
 	return value;
 }
+
+void DSGXSwapBuffers(struct DSGX* gx) {
+	mLOG(DS_GX, STUB, "Unimplemented GX swap buffers");
+	gx->swapBuffers = false;
+
+	// TODO
+	DSGXUpdateGXSTAT(gx);
+	if (CircleBufferSize(&gx->fifo)) {
+		mTimingSchedule(&gx->p->ds9.timing, &gx->fifoEvent, 0);
+	}
+}

src/ds/io.c

@@ -157,6 +157,7 @@ static uint32_t DSIOWrite(struct DSCommon* dscore, uint32_t address, uint16_t va
 	case DS_REG_IF_LO:
 	case DS_REG_IF_HI:
 		value = dscore->memory.io[address >> 1] & ~value;
+		DSGXUpdateGXSTAT(&dscore->p->gx);
 		break;
 	default:
 		return 0;

src/ds/video.c

@@ -289,6 +289,9 @@ void _startHdraw9(struct mTiming* timing, void* context, uint32_t cyclesLate) {
 		video->p->ds9.memory.io[DS_REG_DISPSTAT >> 1] = GBARegisterDISPSTATFillInVblank(dispstat);
 		if (video->frameskipCounter <= 0) {
 			video->renderer->finishFrame(video->renderer);
+			if (video->p->gx.swapBuffers) {
+				DSGXSwapBuffers(&video->p->gx);
+			}
 		}
 		if (GBARegisterDISPSTATIsVblankIRQ(dispstat)) {
 			DSRaiseIRQ(video->p->ds9.cpu, video->p->ds9.memory.io, DS_IRQ_VBLANK);