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feat(ppu): implement vblank, hblank and coincidence interrupts

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This commit is contained in:
Rekai Nyangadzayi Musuka
2023-11-04 03:22:11 -05:00
parent bf08e93508
commit 37aff56c22
4 changed files with 63 additions and 28 deletions
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69
src/core/ppu.zig
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@@ -8,6 +8,8 @@ const Vram = @import("ppu/Vram.zig");
const EngineA = @import("ppu/engine.zig").EngineA;
const EngineB = @import("ppu/engine.zig").EngineB;
const handleInterrupt = @import("emu.zig").handleInterrupt;
pub const screen_width = 256;
pub const screen_height = 192;
const KiB = 0x400;
@@ -59,35 +61,49 @@ pub const Ppu = struct {
}
/// HDraw -> HBlank
pub fn onHdrawEnd(self: *@This(), scheduler: *Scheduler, late: u64) void {
std.debug.assert(self.io.nds9.dispstat.hblank.read() == false);
std.debug.assert(self.io.nds9.dispstat.vblank.read() == false);
pub fn onHdrawEnd(self: *@This(), system: System, scheduler: *Scheduler, late: u64) void {
if (self.io.nds9.dispstat.hblank_irq.read()) {
system.bus9.io.irq.hblank.set();
handleInterrupt(.nds9, system.arm946es);
}
if (self.io.nds7.dispstat.hblank_irq.read()) {
system.bus7.io.irq.hblank.set();
handleInterrupt(.nds7, system.arm7tdmi);
}
// TODO: Run DMAs on HBlank
self.io.nds9.dispstat.hblank.set();
self.io.nds7.dispstat.hblank.set();
// TODO: Signal HBlank IRQ
const dots_in_hblank = 99;
scheduler.push(.{ .nds9 = .hblank }, dots_in_hblank * cycles_per_dot -| late);
}
// VBlank -> HBlank (Still VBlank)
pub fn onVblankEnd(self: *@This(), scheduler: *Scheduler, late: u64) void {
std.debug.assert(!self.io.nds9.dispstat.hblank.read());
std.debug.assert(self.io.nds9.vcount.scanline.read() == 262 or self.io.nds9.dispstat.vblank.read());
/// VBlank -> HBlank (Still VBlank)
pub fn onVblankEnd(self: *@This(), system: System, scheduler: *Scheduler, late: u64) void {
if (self.io.nds9.dispstat.hblank_irq.read()) {
system.bus9.io.irq.hblank.set();
handleInterrupt(.nds9, system.arm946es);
}
if (self.io.nds7.dispstat.hblank_irq.read()) {
system.bus7.io.irq.hblank.set();
handleInterrupt(.nds7, system.arm7tdmi);
}
self.io.nds9.dispstat.hblank.set();
self.io.nds7.dispstat.hblank.set();
// TODO: Signal HBlank IRQ
// TODO: Run DMAs on HBlank
const dots_in_hblank = 99;
scheduler.push(.{ .nds9 = .hblank }, dots_in_hblank * cycles_per_dot -| late);
}
/// HBlank -> HDraw / VBlank
pub fn onHblankEnd(self: *@This(), scheduler: *Scheduler, late: u64) void {
pub fn onHblankEnd(self: *@This(), system: System, scheduler: *Scheduler, late: u64) void {
const scanline_total = 263; // 192 visible, 71 blanking
const prev_scanline = self.io.nds9.vcount.scanline.read();
@@ -102,18 +118,24 @@ pub const Ppu = struct {
{
const coincidence = scanline == self.io.nds9.dispstat.lyc.read();
self.io.nds9.dispstat.coincidence.write(coincidence);
if (coincidence and self.io.nds9.dispstat.vcount_irq.read()) {
system.bus9.io.irq.coincidence.set();
handleInterrupt(.nds9, system.arm946es);
}
}
{
const coincidence = scanline == self.io.nds7.dispstat.lyc.read();
self.io.nds7.dispstat.coincidence.write(coincidence);
if (coincidence and self.io.nds7.dispstat.vcount_irq.read()) {
system.bus7.io.irq.coincidence.set();
handleInterrupt(.nds7, system.arm7tdmi);
}
}
// TODO: LYC == LY IRQ
if (scanline < 192) {
std.debug.assert(self.io.nds9.dispstat.vblank.read() == false);
std.debug.assert(self.io.nds9.dispstat.hblank.read() == false);
// Draw Another Scanline
const dots_in_hdraw = 256;
return scheduler.push(.{ .nds9 = .draw }, dots_in_hdraw * cycles_per_dot -| late);
@@ -123,17 +145,26 @@ pub const Ppu = struct {
// Transition from Hblank to Vblank
self.fb.swap();
if (self.io.nds9.dispstat.vblank_irq.read()) {
system.bus9.io.irq.vblank.set();
handleInterrupt(.nds9, system.arm946es);
}
if (self.io.nds7.dispstat.vblank_irq.read()) {
system.bus7.io.irq.vblank.set();
handleInterrupt(.nds7, system.arm7tdmi);
}
self.io.nds9.dispstat.vblank.set();
self.io.nds7.dispstat.vblank.set();
// TODO: Signal VBlank IRQ
// TODO: Affine BG Latches
// TODO: VBlank DMA Transfers
}
if (scanline == 262) {
self.io.nds9.dispstat.vblank.unset();
self.io.nds7.dispstat.vblank.unset();
std.debug.assert(self.io.nds9.dispstat.vblank.read() == (scanline != 262));
}
const dots_in_vblank = 256;