1#include "gba-video.h"
  2
  3#include "gba.h"
  4#include "gba-io.h"
  5
  6#include <limits.h>
  7
  8static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer);
  9static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer);
 10static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value);
 11static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y);
 12static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer);
 13
 14static struct GBAVideoRenderer dummyRenderer = {
 15	.init = GBAVideoDummyRendererInit,
 16	.deinit = GBAVideoDummyRendererDeinit,
 17	.writeVideoRegister = GBAVideoDummyRendererWriteVideoRegister,
 18	.drawScanline = GBAVideoDummyRendererDrawScanline,
 19	.finishFrame = GBAVideoDummyRendererFinishFrame
 20};
 21
 22void GBAVideoInit(struct GBAVideo* video) {
 23	video->renderer = &dummyRenderer;
 24
 25	video->inHblank = 0;
 26	video->inVblank = 0;
 27	video->vcounter = 0;
 28	video->vblankIRQ = 0;
 29	video->hblankIRQ = 0;
 30	video->vcounterIRQ = 0;
 31	video->vcountSetting = 0;
 32
 33	video->vcount = -1;
 34
 35	video->lastHblank = 0;
 36	video->nextHblank = VIDEO_HDRAW_LENGTH;
 37	video->nextEvent = video->nextHblank;
 38	video->eventDiff = video->nextEvent;
 39
 40	video->nextHblankIRQ = 0;
 41	video->nextVblankIRQ = 0;
 42	video->nextVcounterIRQ = 0;
 43}
 44
 45int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 46	video->nextEvent -= cycles;
 47	if (video->nextEvent <= 0) {
 48		video->lastHblank -= video->eventDiff;
 49		video->nextHblank -= video->eventDiff;
 50		video->nextHblankIRQ -= video->eventDiff;
 51		video->nextVcounterIRQ -= video->eventDiff;
 52
 53		if (video->inHblank) {
 54			// End Hblank
 55			video->inHblank = 0;
 56			video->nextEvent = video->nextHblank;
 57
 58			++video->vcount;
 59			video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
 60
 61			switch (video->vcount) {
 62			case VIDEO_VERTICAL_PIXELS:
 63				video->inVblank = 1;
 64				video->renderer->finishFrame(video->renderer);
 65				video->nextVblankIRQ = video->nextEvent + VIDEO_TOTAL_LENGTH;
 66				//video->cpu.mmu.runVblankDmas();
 67				if (video->vblankIRQ) {
 68					GBARaiseIRQ(video->p, IRQ_VBLANK);
 69				}
 70				//video->vblankCallback();
 71				break;
 72			case VIDEO_VERTICAL_TOTAL_PIXELS - 1:
 73				video->inVblank = 0;
 74				break;
 75			case VIDEO_VERTICAL_TOTAL_PIXELS:
 76				video->vcount = 0;
 77				//video->renderPath.startDraw();
 78				break;
 79			}
 80
 81			video->vcounter = video->vcount == video->vcountSetting;
 82			if (video->vcounter && video->vcounterIRQ) {
 83				GBARaiseIRQ(video->p, IRQ_VCOUNTER);
 84				video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
 85			}
 86
 87			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
 88				video->renderer->drawScanline(video->renderer, video->vcount);
 89			}
 90		} else {
 91			// Begin Hblank
 92			video->inHblank = 1;
 93			video->lastHblank = video->nextHblank;
 94			video->nextEvent = video->lastHblank + VIDEO_HBLANK_LENGTH;
 95			video->nextHblank = video->nextEvent + VIDEO_HDRAW_LENGTH;
 96			video->nextHblankIRQ = video->nextHblank;
 97
 98			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
 99				//video->cpu.mmu.runHblankDmas();
100			}
101			if (video->hblankIRQ) {
102				GBARaiseIRQ(video->p, IRQ_HBLANK);
103			}
104		}
105
106		video->eventDiff = video->nextEvent;
107	}
108	return video->nextEvent;
109}
110
111void GBAVideoWriteDISPSTAT(struct GBAVideo* video, uint16_t value) {
112	video->vblankIRQ = value & 0x0008;
113	video->hblankIRQ = value & 0x0010;
114	video->vcounterIRQ = value & 0x0020;
115	video->vcountSetting = (value & 0xFF00) >> 8;
116
117	if (video->vcounterIRQ) {
118		// FIXME: this can be too late if we're in the middle of an Hblank
119		video->nextVcounterIRQ = video->nextHblank + VIDEO_HBLANK_LENGTH + (video->vcountSetting - video->vcount) * VIDEO_HORIZONTAL_LENGTH;
120		if (video->nextVcounterIRQ < video->nextEvent) {
121			video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
122		}
123	}
124}
125
126uint16_t GBAVideoReadDISPSTAT(struct GBAVideo* video) {
127	return (video->inVblank) | (video->inHblank << 1) | (video->vcounter << 2);
128}
129
130static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer) {
131	(void)(renderer);
132	// Nothing to do
133}
134
135static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer) {
136	(void)(renderer);
137	// Nothing to do
138}
139static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value) {
140	(void)(renderer);
141	(void)(address);
142	return value;
143}
144
145static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y) {
146	(void)(renderer);
147	(void)(y);
148	// Nothing to do
149}
150
151static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer) {
152	(void)(renderer);
153	printf("Drawing a frame\n");
154	// Nothing to do
155}