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GB: Revamp STAT register

This commit is contained in:
Jeffrey Pfau 2016-01-17 00:25:52 -08:00
parent b711432a5e
commit 31b509e033
3 changed files with 52 additions and 10 deletions
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3
src/gb/io.c
View File

@ -21,6 +21,9 @@ void GBIOWrite(struct GB* gb, unsigned address, uint8_t value) {
// TODO: handle GBC differences
GBVideoWriteLCDC(&gb->video, value);
break;
case REG_STAT:
GBVideoWriteSTAT(&gb->video, value);
break;
case REG_IE:
gb->memory.ie = value;
GBUpdateIRQs(gb);

51
src/gb/video.c
View File

@ -77,27 +77,52 @@ int32_t GBVideoProcessEvents(struct GBVideo* video, int32_t cycles) {
video->nextMode -= video->eventDiff;
}
if (video->nextMode <= 0) {
video->mode = (video->mode + 1) & 3;
switch (video->mode) {
case 0:
video->nextMode = GB_VIDEO_MODE_0_LENGTH;
break;
case 1:
video->nextMode = GB_VIDEO_MODE_1_LENGTH;
break;
case 2:
video->nextMode = GB_VIDEO_MODE_2_LENGTH;
++video->ly;
video->p->memory.io[REG_LY] = video->ly;
if (video->ly >= GB_VIDEO_VERTICAL_TOTAL_PIXELS) {
video->ly = 0;
++video->frameCounter;
video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
video->mode = 1;
if (GBRegisterSTATIsVblankIRQ(video->stat)) {
video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
}
video->p->memory.io[REG_IF] |= (1 << GB_IRQ_VBLANK);
GBUpdateIRQs(video->p);
} else {
video->nextMode = GB_VIDEO_MODE_2_LENGTH;
video->mode = 2;
if (GBRegisterSTATIsOAMIRQ(video->stat)) {
video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
GBUpdateIRQs(video->p);
}
}
video->p->memory.io[REG_LY] = video->ly;
break;
case 1:
video->nextMode = GB_VIDEO_MODE_2_LENGTH;
video->mode = 2;
if (GBRegisterSTATIsOAMIRQ(video->stat)) {
video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
GBUpdateIRQs(video->p);
}
break;
case 2:
video->nextMode = GB_VIDEO_MODE_3_LENGTH;
video->mode = 3;
break;
case 3:
video->nextMode = GB_VIDEO_MODE_3_LENGTH;
video->nextMode = GB_VIDEO_MODE_0_LENGTH;
video->mode = 0;
if (GBRegisterSTATIsHblankIRQ(video->stat)) {
video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
GBUpdateIRQs(video->p);
}
break;
}
video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
video->p->memory.io[REG_STAT] = video->stat;
}
video->nextEvent = video->nextMode;
@ -112,6 +137,8 @@ void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value) {
video->mode = 2;
video->nextMode = GB_VIDEO_MODE_2_LENGTH;
video->nextEvent = video->nextMode;
video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
video->p->memory.io[REG_STAT] = video->stat;
video->eventDiff = 0;
if (video->nextEvent < video->p->cpu->nextEvent) {
video->p->cpu->nextEvent = video->nextEvent;
@ -120,6 +147,10 @@ void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value) {
}
}
void GBVideoWriteSTAT(struct GBVideo* video, GBRegisterSTAT value) {
video->stat = (video->stat & 0x7) | (value & 0x78);
}
static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer) {
UNUSED(renderer);
// Nothing to do

8
src/gb/video.h
View File

@ -46,12 +46,20 @@ DECL_BITFIELD(GBRegisterLCDC, uint8_t);
DECL_BIT(GBRegisterLCDC, Enable, 7);
DECL_BITFIELD(GBRegisterSTAT, uint8_t);
DECL_BITS(GBRegisterSTAT, Mode, 0, 2);
DECL_BIT(GBRegisterSTAT, LYC, 2);
DECL_BIT(GBRegisterSTAT, HblankIRQ, 3);
DECL_BIT(GBRegisterSTAT, VblankIRQ, 4);
DECL_BIT(GBRegisterSTAT, OAMIRQ, 5);
DECL_BIT(GBRegisterSTAT, LYCIRQ, 6);
struct GBVideo {
struct GB* p;
struct GBVideoRenderer* renderer;
int ly;
GBRegisterSTAT stat;
int mode;
int32_t nextEvent;