1#include "gba-video.h"
  2
  3#include "gba.h"
  4#include "gba-io.h"
  5#include "gba-serialize.h"
  6#include "gba-thread.h"
  7#include "memory.h"
  8
  9#include <limits.h>
 10#include <string.h>
 11
 12static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer);
 13static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer);
 14static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value);
 15static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y);
 16static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer);
 17
 18static struct GBAVideoRenderer dummyRenderer = {
 19	.init = GBAVideoDummyRendererInit,
 20	.deinit = GBAVideoDummyRendererDeinit,
 21	.writeVideoRegister = GBAVideoDummyRendererWriteVideoRegister,
 22	.drawScanline = GBAVideoDummyRendererDrawScanline,
 23	.finishFrame = GBAVideoDummyRendererFinishFrame
 24};
 25
 26void GBAVideoInit(struct GBAVideo* video) {
 27	video->renderer = &dummyRenderer;
 28
 29	video->inHblank = 0;
 30	video->inVblank = 0;
 31	video->vcounter = 0;
 32	video->vblankIRQ = 0;
 33	video->hblankIRQ = 0;
 34	video->vcounterIRQ = 0;
 35	video->vcountSetting = 0;
 36
 37	video->vcount = -1;
 38
 39	video->lastHblank = 0;
 40	video->nextHblank = VIDEO_HDRAW_LENGTH;
 41	video->nextEvent = video->nextHblank;
 42	video->eventDiff = video->nextEvent;
 43
 44	video->nextHblankIRQ = 0;
 45	video->nextVblankIRQ = 0;
 46	video->nextVcounterIRQ = 0;
 47
 48	video->vram = anonymousMemoryMap(SIZE_VRAM);
 49}
 50
 51void GBAVideoDeinit(struct GBAVideo* video) {
 52	GBAVideoAssociateRenderer(video, &dummyRenderer);
 53	mappedMemoryFree(video->vram, SIZE_VRAM);
 54}
 55
 56void GBAVideoAssociateRenderer(struct GBAVideo* video, struct GBAVideoRenderer* renderer) {
 57	video->renderer->deinit(video->renderer);
 58	video->renderer = renderer;
 59	renderer->palette = video->palette;
 60	renderer->vram = video->vram;
 61	renderer->oam = &video->oam;
 62	video->renderer->init(video->renderer);
 63}
 64
 65int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 66	video->nextEvent -= cycles;
 67	video->eventDiff += cycles;
 68	if (video->nextEvent <= 0) {
 69		video->lastHblank -= video->eventDiff;
 70		video->nextHblank -= video->eventDiff;
 71		video->nextHblankIRQ -= video->eventDiff;
 72		video->nextVcounterIRQ -= video->eventDiff;
 73
 74		if (video->inHblank) {
 75			// End Hblank
 76			video->inHblank = 0;
 77			video->nextEvent = video->nextHblank;
 78
 79			++video->vcount;
 80			video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
 81
 82			switch (video->vcount) {
 83			case VIDEO_VERTICAL_PIXELS:
 84				video->inVblank = 1;
 85				if (GBASyncDrawingFrame(video->p->sync)) {
 86					video->renderer->finishFrame(video->renderer);
 87				}
 88				video->nextVblankIRQ = video->nextEvent + VIDEO_TOTAL_LENGTH;
 89				GBAMemoryRunVblankDMAs(&video->p->memory);
 90				if (video->vblankIRQ) {
 91					GBARaiseIRQ(video->p, IRQ_VBLANK);
 92				}
 93				GBASyncPostFrame(video->p->sync);
 94				break;
 95			case VIDEO_VERTICAL_TOTAL_PIXELS - 1:
 96				video->inVblank = 0;
 97				break;
 98			case VIDEO_VERTICAL_TOTAL_PIXELS:
 99				video->vcount = 0;
100				video->p->memory.io[REG_VCOUNT >> 1] = 0;
101				break;
102			}
103
104			video->vcounter = video->vcount == video->vcountSetting;
105			if (video->vcounter && video->vcounterIRQ) {
106				GBARaiseIRQ(video->p, IRQ_VCOUNTER);
107				video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
108			}
109
110			if (video->vcount < VIDEO_VERTICAL_PIXELS && GBASyncDrawingFrame(video->p->sync)) {
111				video->renderer->drawScanline(video->renderer, video->vcount);
112			}
113		} else {
114			// Begin Hblank
115			video->inHblank = 1;
116			video->lastHblank = video->nextHblank;
117			video->nextEvent = video->lastHblank + VIDEO_HBLANK_LENGTH;
118			video->nextHblank = video->nextEvent + VIDEO_HDRAW_LENGTH;
119			video->nextHblankIRQ = video->nextHblank;
120
121			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
122				GBAMemoryRunHblankDMAs(&video->p->memory);
123			}
124			if (video->hblankIRQ) {
125				GBARaiseIRQ(video->p, IRQ_HBLANK);
126			}
127		}
128
129		video->eventDiff = 0;
130	}
131	return video->nextEvent;
132}
133
134void GBAVideoWriteDISPSTAT(struct GBAVideo* video, uint16_t value) {
135	union GBARegisterDISPSTAT dispstat;
136	dispstat.packed = value;
137	video->vblankIRQ = dispstat.vblankIRQ;
138	video->hblankIRQ = dispstat.hblankIRQ;
139	video->vcounterIRQ = dispstat.vcounterIRQ;
140	video->vcountSetting = dispstat.vcountSetting;
141
142	if (video->vcounterIRQ) {
143		// FIXME: this can be too late if we're in the middle of an Hblank
144		video->nextVcounterIRQ = video->nextHblank + VIDEO_HBLANK_LENGTH + (video->vcountSetting - video->vcount) * VIDEO_HORIZONTAL_LENGTH;
145		if (video->nextVcounterIRQ < video->nextEvent) {
146			video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
147		}
148	}
149}
150
151uint16_t GBAVideoReadDISPSTAT(struct GBAVideo* video) {
152	return (video->inVblank) | (video->inHblank << 1) | (video->vcounter << 2);
153}
154
155static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer) {
156	(void)(renderer);
157	// Nothing to do
158}
159
160static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer) {
161	(void)(renderer);
162	// Nothing to do
163}
164
165static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value) {
166	(void)(renderer);
167	(void)(address);
168	return value;
169}
170
171static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y) {
172	(void)(renderer);
173	(void)(y);
174	// Nothing to do
175}
176
177static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer) {
178	(void)(renderer);
179	// Nothing to do
180}
181
182void GBAVideoSerialize(struct GBAVideo* video, struct GBASerializedState* state) {
183	memcpy(state->vram, video->renderer->vram, SIZE_VRAM);
184	memcpy(state->oam, video->oam.raw, SIZE_OAM);
185	memcpy(state->pram, video->palette, SIZE_PALETTE_RAM);
186	union GBARegisterDISPSTAT dispstat;
187	dispstat.inVblank = video->inVblank;
188	dispstat.inHblank = video->inHblank;
189	dispstat.vcounter = video->vcounter;
190	dispstat.vblankIRQ = video->vblankIRQ;
191	dispstat.hblankIRQ = video->hblankIRQ;
192	dispstat.vcounterIRQ = video->vcounterIRQ;
193	dispstat.vcountSetting = video->vcountSetting;
194	state->io[REG_DISPSTAT >> 1] = dispstat.packed;
195	state->video.nextEvent = video->nextEvent;
196	state->video.eventDiff = video->eventDiff;
197	state->video.lastHblank = video->lastHblank;
198	state->video.nextHblank = video->nextHblank;
199	state->video.nextHblankIRQ = video->nextHblankIRQ;
200	state->video.nextVblankIRQ = video->nextVblankIRQ;
201	state->video.nextVcounterIRQ = video->nextVcounterIRQ;
202}
203
204void GBAVideoDeserialize(struct GBAVideo* video, struct GBASerializedState* state) {
205	memcpy(video->renderer->vram, state->vram, SIZE_VRAM);
206	memcpy(video->oam.raw, state->oam, SIZE_OAM);
207	int i;
208	for (i = 0; i < SIZE_PALETTE_RAM; i += 2) {
209		GBAStore16(&video->p->memory.d, BASE_PALETTE_RAM | i, state->pram[i >> 1], 0);
210	}
211	union GBARegisterDISPSTAT dispstat;
212	dispstat.packed = state->io[REG_DISPSTAT >> 1];
213	video->inVblank = dispstat.inVblank;
214	video->inHblank = dispstat.inHblank;
215	video->vcounter = dispstat.vcounter;
216	video->vblankIRQ = dispstat.vblankIRQ;
217	video->hblankIRQ = dispstat.hblankIRQ;
218	video->vcounterIRQ = dispstat.vcounterIRQ;
219	video->vcountSetting = dispstat.vcountSetting;
220	video->nextEvent = state->video.nextEvent;
221	video->eventDiff = state->video.eventDiff;
222	video->lastHblank = state->video.lastHblank;
223	video->nextHblank = state->video.nextHblank;
224	video->nextHblankIRQ = state->video.nextHblankIRQ;
225	video->nextVblankIRQ = state->video.nextVblankIRQ;
226	video->nextVcounterIRQ = state->video.nextVcounterIRQ;
227	video->vcount = state->io[REG_VCOUNT >> 1];
228}