chore: reimplement alpha blending

window wrap now works (it's pretty slow though?)

README.md

@@ -28,45 +28,31 @@ Finally it's worth noting that ZBA uses a TOML config file it'll store in your O
 
 ## Tests
 
-GBA Tests | [jsmolka](https://github.com/jsmolka/)
---- | ---
-`arm.gba`,  `thumb.gba` | PASS
-`memory.gba`, `bios.gba` | PASS
-`flash64.gba`, `flash128.gba` | PASS
-`sram.gba` | PASS
-`none.gba` | PASS
-`hello.gba`, `shades.gba`, `stripes.gba` | PASS
-`nes.gba` | PASS
-
-GBARoms | [DenSinH](https://github.com/DenSinH/)
---- | ---
-`eeprom-test`, `flash-test` | PASS
-`midikey2freq` | PASS
-`swi-tests-random` | FAIL
-
-gba_tests | [destoer](https://github.com/destoer/)
---- | ---
-`cond_invalid.gba` | PASS
-`dma_priority.gba` | PASS
-`hello_world.gba` | PASS
-`if_ack.gba` | PASS
-`line_timing.gba` | FAIL
-`lyc_midline.gba` | FAIL
-`window_midframe.gba` | FAIL
-
-GBA Test Collection | [ladystarbreeze](https://github.com/ladystarbreeze)
---- | ---
-`retAddr.gba` | PASS
-`helloWorld.gba` | PASS
-`helloAudio.gba` | PASS
-
-FuzzARM | [DenSinH](https://github.com/DenSinH/)
---- | ---
-`main.gba` | PASS
-
-arm7wrestler GBA Fixed | [destoer](https://github.com/destoer)
---- | ---
-`armwrestler-gba-fixed.gba` | PASS
+- [x] [jsmolka's GBA Test Collection](https://github.com/jsmolka/gba-tests)
+  - [x] `arm.gba` and `thumb.gba`
+  - [x] `flash64.gba`, `flash128.gba`, `none.gba`, and `sram.gba`
+  - [x] `hello.gba`, `shades.gba`, and `stripes.gba`
+  - [x] `memory.gba`
+  - [x] `bios.gba`
+  - [x] `nes.gba`
+- [ ] [DenSinH's GBA ROMs](https://github.com/DenSinH/GBARoms)
+  - [x] `eeprom-test` and `flash-test`
+  - [x] `midikey2freq`
+  - [ ] `swi-tests-random`
+- [ ] [destoer's GBA Tests](https://github.com/destoer/gba_tests)
+  - [x] `cond_invalid.gba`
+  - [x] `dma_priority.gba`
+  - [x] `hello_world.gba`
+  - [x] `if_ack.gba`
+  - [ ] `line_timing.gba`
+  - [ ] `lyc_midline.gba`
+  - [ ] `window_midframe.gba`
+- [x] [ladystarbreeze's GBA Test Collection](https://github.com/ladystarbreeze/GBA-Test-Collection)
+  - [x] `retAddr.gba`
+  - [x] `helloWorld.gba`
+  - [x] `helloAudio.gba`
+- [x] [`armwrestler-gba-fixed.gba`](https://github.com/destoer/armwrestler-gba-fixed)
+- [x] [FuzzARM](https://github.com/DenSinH/FuzzARM)
 
 ## Resources
 
@@ -77,19 +63,19 @@ arm7wrestler GBA Fixed | [destoer](https://github.com/destoer)
 
 ## Compiling
 
-Most recently built on Zig [0.11.0-dev.368+1829b6eab](https://github.com/ziglang/zig/tree/1829b6eab)
+Most recently built on Zig [v0.11.0-dev.144+892fb0fc8](https://github.com/ziglang/zig/tree/892fb0fc8)
 
 ### Dependencies
 
-Dependency | Source
---- | ---
-SDL.zig | <https://github.com/MasterQ32/SDL.zig>
-zig-clap | <https://github.com/Hejsil/zig-clap>
-known-folders | <https://github.com/ziglibs/known-folders>
-zig-toml | <https://github.com/aeronavery/zig-toml>
-zig-datetime | <https://github.com/frmdstryr/zig-datetime>
-`bitfields.zig` | [https://github.com/FlorenceOS/Florence](https://github.com/FlorenceOS/Florence/blob/aaa5a9e568/lib/util/bitfields.zig)
-`gl.zig` | <https://github.com/MasterQ32/zig-opengl>
+- [SDL.zig](https://github.com/MasterQ32/SDL.zig)
+  - [SDL2](https://www.libsdl.org/download-2.0.php)
+- [zig-clap](https://github.com/Hejsil/zig-clap)
+- [known-folders](https://github.com/ziglibs/known-folders)
+- [zig-toml](https://github.com/aeronavery/zig-toml)
+- [zig-datetime](https://github.com/frmdstryr/zig-datetime)
+- [`bitfields.zig`](https://github.com/FlorenceOS/Florence/blob/aaa5a9e568/lib/util/bitfields.zig)
+
+`bitfields.zig` from [FlorenceOS](https://github.com/FlorenceOS) is included under `lib/util/bitfield.zig`.
 
 Use `git submodule update --init` from the project root to pull the git submodules `SDL.zig`, `zig-clap`, `known-folders`, `zig-toml` and `zig-datetime`
 

build.zig

@@ -1,15 +1,7 @@
 const std = @import("std");
-const builtin = @import("builtin");
 const Sdk = @import("lib/SDL.zig/Sdk.zig");
 
 pub fn build(b: *std.build.Builder) void {
-    // Minimum Zig Version
-    const min_ver = std.SemanticVersion.parse("0.11.0-dev.323+30eb2a175") catch return; // https://github.com/ziglang/zig/commit/30eb2a175
-    if (builtin.zig_version.order(min_ver).compare(.lt)) {
-        std.log.err("{s}", .{b.fmt("Zig v{} does not meet the minimum version requirement. (Zig v{})", .{ builtin.zig_version, min_ver })});
-        std.os.exit(1);
-    }
-
     // Standard target options allows the person running `zig build` to choose
     // what target to build for. Here we do not override the defaults, which
     // means any target is allowed, and the default is native. Other options

lib/SDL.zig

@@ -1 +1 @@
-Subproject commit 00b43568854f14e3bab340a4e062776ecb44a727
+Subproject commit 6a9e37687a4b9ae3c14c9ea148ec51d14e01c7db

lib/zig-clap

@@ -1 +1 @@
-Subproject commit a1b01ffeab452790790034b8a0e97aa30bbeb800
+Subproject commit 749c43f1f846adc950a5920ed61b40cbc3ec2c54

lib/zig-toml

@@ -1 +1 @@
-Subproject commit 016b8bcf98e50ae9408f6a9606bbec5a9bc6f677
+Subproject commit be26d500917b5b3af4708f62ce22b990032a0ad3

src/config.zig

@@ -58,10 +58,7 @@ pub fn load(allocator: Allocator, file_path: []const u8) !void {
     const contents = try config_file.readToEndAlloc(allocator, try config_file.getEndPos());
     defer allocator.free(contents);
 
-    var parser = try toml.parseFile(allocator, file_path);
-    defer parser.deinit();
-
-    const table = try parser.parse();
+    const table = try toml.parseContents(allocator, contents, null);
     defer table.deinit();
 
     // TODO: Report unknown config options

src/core/Bus.zig

@@ -311,7 +311,7 @@ pub fn read(self: *Self, comptime T: type, unaligned_address: u32) T {
     self.sched.tick += timings[@boolToInt(T == u32)][@truncate(u4, unaligned_address >> 24)];
 
     // We're doing some serious out-of-bounds open-bus reads
-    if (page >= table_len) return self.openBus(T, unaligned_address);
+    if (page > table_len) return self.openBus(T, unaligned_address);
 
     if (self.read_table[page]) |some_ptr| {
         // We have a pointer to a page, cast the pointer to it's underlying type
@@ -377,7 +377,7 @@ pub fn write(self: *Self, comptime T: type, unaligned_address: u32, value: T) vo
     self.sched.tick += timings[@boolToInt(T == u32)][@truncate(u4, unaligned_address >> 24)];
 
     // We're doing some serious out-of-bounds open-bus writes, they do nothing though
-    if (page >= table_len) return;
+    if (page > table_len) return;
 
     if (self.write_tables[@boolToInt(T == u8)][page]) |some_ptr| {
         // We have a pointer to a page, cast the pointer to it's underlying type

src/core/apu.zig

@@ -108,14 +108,8 @@ pub fn read(comptime T: type, apu: *const Apu, addr: u32) ?T {
 pub fn write(comptime T: type, apu: *Apu, addr: u32, value: T) void {
     const byte_addr = @truncate(u8, addr);
 
-    if (byte_addr <= 0x81 and !apu.cnt.apu_enable.read()) return;
-
     switch (T) {
-        u32 => {
-            // 0x80 and 0x81 handled in setSoundCnt
-            if (byte_addr < 0x80 and !apu.cnt.apu_enable.read()) return;
-
-            switch (byte_addr) {
+        u32 => switch (byte_addr) {
             0x60 => apu.ch1.setSound1Cnt(value),
             0x64 => apu.ch1.setSound1CntX(&apu.fs, @truncate(u16, value)),
 
@@ -137,12 +131,8 @@ pub fn write(comptime T: type, apu: *Apu, addr: u32, value: T) void {
             0xA0 => apu.chA.push(value), // FIFO_A
             0xA4 => apu.chB.push(value), // FIFO_B
             else => util.io.write.undef(log, "Tried to write 0x{X:0>8}{} to 0x{X:0>8}", .{ value, T, addr }),
-            }
         },
-        u16 => {
-            if (byte_addr <= 0x81 and !apu.cnt.apu_enable.read()) return;
-
-            switch (byte_addr) {
+        u16 => switch (byte_addr) {
             0x60 => apu.ch1.setSound1CntL(@truncate(u8, value)), // SOUND1CNT_L
             0x62 => apu.ch1.setSound1CntH(value),
             0x64 => apu.ch1.setSound1CntX(&apu.fs, value),
@@ -174,12 +164,8 @@ pub fn write(comptime T: type, apu: *Apu, addr: u32, value: T) void {
             0xA0, 0xA2 => log.err("Tried to write 0x{X:0>4}{} to FIFO_A", .{ value, T }),
             0xA4, 0xA6 => log.err("Tried to write 0x{X:0>4}{} to FIFO_B", .{ value, T }),
             else => util.io.write.undef(log, "Tried to write 0x{X:0>4}{} to 0x{X:0>8}", .{ value, T, addr }),
-            }
         },
-        u8 => {
-            if (byte_addr <= 0x81 and !apu.cnt.apu_enable.read()) return;
-
-            switch (byte_addr) {
+        u8 => switch (byte_addr) {
             0x60 => apu.ch1.setSound1CntL(value),
             0x61 => {},
             0x62 => apu.ch1.setNr11(value),
@@ -222,7 +208,6 @@ pub fn write(comptime T: type, apu: *Apu, addr: u32, value: T) void {
             0xA0...0xA3 => log.err("Tried to write 0x{X:0>2}{} to FIFO_A", .{ value, T }),
             0xA4...0xA7 => log.err("Tried to write 0x{X:0>2}{} to FIFO_B", .{ value, T }),
             else => util.io.write.undef(log, "Tried to write 0x{X:0>2}{} to 0x{X:0>8}", .{ value, T, addr }),
-            }
         },
         else => @compileError("APU: Unsupported write width"),
     }
@@ -290,20 +275,15 @@ pub const Apu = struct {
     }
 
     fn reset(self: *Self) void {
-        // All PSG Registers between 0x0400_0060..0x0400_0081 are zeroed
-        // 0x0400_0082 and 0x0400_0088 retain their values
         self.ch1.reset();
         self.ch2.reset();
         self.ch3.reset();
         self.ch4.reset();
-
-        // GBATEK says 4000060h..4000081h I take this to mean inclusive
-        self.psg_cnt.raw = 0x0000;
     }
 
     /// SOUNDCNT
     fn setSoundCnt(self: *Self, value: u32) void {
-        if (self.cnt.apu_enable.read()) self.setSoundCntL(@truncate(u16, value));
+        self.setSoundCntL(@truncate(u16, value));
         self.setSoundCntH(@truncate(u16, value >> 16));
     }
 
@@ -342,14 +322,11 @@ pub const Apu = struct {
             self.fs.step = 0; // Reset Frame Sequencer
 
             // Reset Square Wave Offsets
-            self.ch1.square.reset();
-            self.ch2.square.reset();
+            self.ch1.square.pos = 0;
+            self.ch2.square.pos = 0;
 
-            // Reset Wave
-            self.ch3.wave_dev.reset();
-
-            // Rest Noise
-            self.ch4.lfsr.reset();
+            // Reset Wave Device Offsets
+            self.ch3.wave_dev.offset = 0;
         } else {
             self.reset();
         }
@@ -418,8 +395,8 @@ pub const Apu = struct {
         right += if (self.dma_cnt.chB_right.read()) chB_sample else 0;
 
         // Add SOUNDBIAS
-        // FIXME: SOUNDBIAS is 10-bit but The waveform is centered around 0 if I treat it as 11-bit
-        const bias = @as(i16, self.bias.level.read()) << 2;
+        // FIXME: Is SOUNDBIAS 9-bit or 10-bit?
+        const bias = @as(i16, self.bias.level.read()) << 1;
         left += bias;
         right += bias;
 

src/core/apu/Noise.zig

@@ -49,13 +49,10 @@ pub fn init(sched: *Scheduler) Self {
 }
 
 pub fn reset(self: *Self) void {
-    self.len = 0; // NR41
-    self.envelope.raw = 0; // NR42
-    self.poly.raw = 0; // NR43
-    self.cnt.raw = 0; // NR44
-
-    self.len_dev.reset();
-    self.env_dev.reset();
+    self.len = 0;
+    self.envelope.raw = 0;
+    self.poly.raw = 0;
+    self.cnt.raw = 0;
 
     self.sample = 0;
     self.enabled = false;

src/core/apu/Tone.zig

@@ -43,12 +43,9 @@ pub fn init(sched: *Scheduler) Self {
 }
 
 pub fn reset(self: *Self) void {
-    self.duty.raw = 0; // NR21
-    self.envelope.raw = 0; // NR22
-    self.freq.raw = 0; // NR32, NR24
-
-    self.len_dev.reset();
-    self.env_dev.reset();
+    self.duty.raw = 0;
+    self.envelope.raw = 0;
+    self.freq.raw = 0;
 
     self.sample = 0;
     self.enabled = false;

src/core/apu/ToneSweep.zig

@@ -50,14 +50,12 @@ pub fn init(sched: *Scheduler) Self {
 }
 
 pub fn reset(self: *Self) void {
-    self.sweep.raw = 0; // NR10
-    self.duty.raw = 0; // NR11
-    self.envelope.raw = 0; // NR12
-    self.freq.raw = 0; // NR13, NR14
+    self.sweep.raw = 0;
+    self.sweep_dev.calc_performed = false;
 
-    self.len_dev.reset();
-    self.sweep_dev.reset();
-    self.env_dev.reset();
+    self.duty.raw = 0;
+    self.envelope.raw = 0;
+    self.freq.raw = 0;
 
     self.sample = 0;
     self.enabled = false;

src/core/apu/Wave.zig

@@ -42,13 +42,10 @@ pub fn init(sched: *Scheduler) Self {
 }
 
 pub fn reset(self: *Self) void {
-    self.select.raw = 0; // NR30
-    self.length = 0; // NR31
-    self.vol.raw = 0; // NR32
-    self.freq.raw = 0; // NR33, NR34
-
-    self.len_dev.reset();
-    self.wave_dev.reset();
+    self.select.raw = 0;
+    self.length = 0;
+    self.vol.raw = 0;
+    self.freq.raw = 0;
 
     self.sample = 0;
     self.enabled = false;

src/core/apu/device/Envelope.zig

@@ -11,11 +11,6 @@ pub fn create() Self {
     return .{ .timer = 0, .vol = 0 };
 }
 
-pub fn reset(self: *Self) void {
-    self.timer = 0;
-    self.vol = 0;
-}
-
 pub fn tick(self: *Self, nrx2: io.Envelope) void {
     if (nrx2.period.read() != 0) {
         if (self.timer != 0) self.timer -= 1;

src/core/apu/device/Length.zig

@@ -6,10 +6,6 @@ pub fn create() Self {
     return .{ .timer = 0 };
 }
 
-pub fn reset(self: *Self) void {
-    self.timer = 0;
-}
-
 pub fn tick(self: *Self, enabled: bool, ch_enable: *bool) void {
     if (enabled) {
         if (self.timer == 0) return;

src/core/apu/device/Sweep.zig

@@ -18,13 +18,6 @@ pub fn create() Self {
     };
 }
 
-pub fn reset(self: *Self) void {
-    self.timer = 0;
-    self.enabled = false;
-    self.shadow = 0;
-    self.calc_performed = false;
-}
-
 pub fn tick(self: *Self, ch1: *ToneSweep) void {
     if (self.timer != 0) self.timer -= 1;
 

src/core/apu/signal/Lfsr.zig

@@ -19,11 +19,6 @@ pub fn create(sched: *Scheduler) Self {
     };
 }
 
-pub fn reset(self: *Self) void {
-    self.shift = 0;
-    self.timer = 0;
-}
-
 pub fn sample(self: *const Self) i8 {
     return if ((~self.shift & 1) == 1) 1 else -1;
 }

src/core/apu/signal/Square.zig

@@ -20,11 +20,6 @@ pub fn init(sched: *Scheduler) Self {
     };
 }
 
-pub fn reset(self: *Self) void {
-    self.timer = 0;
-    self.pos = 0;
-}
-
 /// Scheduler Event Handler for Square Synth Timer Expire
 pub fn onSquareTimerExpire(self: *Self, comptime T: type, nrx34: io.Frequency, late: u64) void {
     comptime std.debug.assert(T == ToneSweep or T == Tone);

src/core/apu/signal/Wave.zig

@@ -38,13 +38,6 @@ pub fn init(sched: *Scheduler) Self {
     };
 }
 
-pub fn reset(self: *Self) void {
-    self.timer = 0;
-    self.offset = 0;
-
-    // sample buffer isn't reset because it's outside of the range of what NR52{7}'s effects
-}
-
 /// Reload internal Wave Timer
 pub fn reload(self: *Self, value: u11) void {
     self.sched.removeScheduledEvent(.{ .ApuChannel = 2 });

src/core/bus/dma.zig

@@ -5,7 +5,7 @@ const DmaControl = @import("io.zig").DmaControl;
 const Bus = @import("../Bus.zig");
 const Arm7tdmi = @import("../cpu.zig").Arm7tdmi;
 
-pub const DmaTuple = struct { DmaController(0), DmaController(1), DmaController(2), DmaController(3) };
+pub const DmaTuple = std.meta.Tuple(&[_]type{ DmaController(0), DmaController(1), DmaController(2), DmaController(3) });
 const log = std.log.scoped(.DmaTransfer);
 
 const getHalf = util.getHalf;
@@ -256,16 +256,11 @@ fn DmaController(comptime id: u2) type {
                 cpu.bus.write(u16, dad_addr, @truncate(u16, rotr(u32, self.data_latch, 8 * (dad_addr & 3))));
             }
 
-            switch (@truncate(u8, sad_addr >> 24)) {
-                // according to fleroviux, DMAs with a source address in ROM misbehave
-                // the resultant behaviour is that the source address will increment despite what DMAXCNT says
-                0x08...0x0D => self.sad_latch +%= offset, // obscure behaviour
-                else => switch (sad_adj) {
+            switch (sad_adj) {
                 .Increment => self.sad_latch +%= offset,
                 .Decrement => self.sad_latch -%= offset,
                 .IncrementReload => log.err("{} is a prohibited adjustment on SAD", .{sad_adj}),
                 .Fixed => {},
-                },
             }
 
             switch (dad_adj) {

src/core/bus/io.zig

@@ -24,14 +24,14 @@ pub const Io = struct {
     postflg: PostFlag,
     waitcnt: WaitControl,
     haltcnt: HaltControl,
-    keyinput: AtomicKeyInput,
+    keyinput: KeyInput,
 
     pub fn init() Self {
         return .{
             .ime = false,
             .ie = .{ .raw = 0x0000 },
             .irq = .{ .raw = 0x0000 },
-            .keyinput = AtomicKeyInput.init(.{ .raw = 0x03FF }),
+            .keyinput = .{ .raw = 0x03FF },
             .waitcnt = .{ .raw = 0x0000_0000 }, // Bit 15 == 0 for GBA
             .postflg = .FirstBoot,
             .haltcnt = .Execute,
@@ -92,7 +92,7 @@ pub fn read(bus: *const Bus, comptime T: type, address: u32) ?T {
             0x0400_0128 => util.io.read.todo(log, "Read {} from SIOCNT", .{T}),
 
             // Keypad Input
-            0x0400_0130 => bus.io.keyinput.load(.Monotonic).raw,
+            0x0400_0130 => bus.io.keyinput.raw,
 
             // Serial Communication 2
             0x0400_0134 => util.io.read.todo(log, "Read {} from RCNT", .{T}),
@@ -376,31 +376,6 @@ const KeyInput = extern union {
     raw: u16,
 };
 
-const AtomicKeyInput = struct {
-    const Self = @This();
-    const Ordering = std.atomic.Ordering;
-
-    inner: KeyInput,
-
-    pub fn init(value: KeyInput) Self {
-        return .{ .inner = value };
-    }
-
-    pub inline fn load(self: *const Self, comptime ordering: Ordering) KeyInput {
-        return .{ .raw = switch (ordering) {
-            .AcqRel, .Release => @compileError("not supported for atomic loads"),
-            else => @atomicLoad(u16, &self.inner.raw, ordering),
-        } };
-    }
-
-    pub inline fn store(self: *Self, value: u16, comptime ordering: Ordering) void {
-        switch (ordering) {
-            .AcqRel, .Acquire => @compileError("not supported for atomic stores"),
-            else => @atomicStore(u16, &self.inner.raw, value, ordering),
-        }
-    }
-};
-
 // Read / Write
 pub const BackgroundControl = extern union {
     priority: Bitfield(u16, 0, 2),

src/core/bus/timer.zig

@@ -5,7 +5,7 @@ const TimerControl = @import("io.zig").TimerControl;
 const Scheduler = @import("../scheduler.zig").Scheduler;
 const Arm7tdmi = @import("../cpu.zig").Arm7tdmi;
 
-pub const TimerTuple = struct { Timer(0), Timer(1), Timer(2), Timer(3) };
+pub const TimerTuple = std.meta.Tuple(&[_]type{ Timer(0), Timer(1), Timer(2), Timer(3) });
 const log = std.log.scoped(.Timer);
 
 const getHalf = util.getHalf;
@@ -150,35 +150,20 @@ fn Timer(comptime id: u2) type {
         pub fn setTimcntH(self: *Self, halfword: u16) void {
             const new = TimerControl{ .raw = halfword };
 
-            if (self.cnt.enabled.read()) {
-                // timer was already enabled
-
-                // If enabled falling edge or cascade falling edge, timer is paused
-                if (!new.enabled.read() or (!self.cnt.cascade.read() and new.cascade.read())) {
+            // If Timer happens to be enabled, It will either be resheduled or disabled
             self.sched.removeScheduledEvent(.{ .TimerOverflow = id });
 
-                    // Counter should hold the value it stopped at meaning we have to calculate it now
+            if (self.cnt.enabled.read() and (new.cascade.read() or !new.enabled.read())) {
+                // Either through the cascade bit or the enable bit, the timer has effectively been disabled
+                // The Counter should hold whatever value it should have been at when it was disabled
                 self._counter +%= @truncate(u16, (self.sched.now() - self._start_timestamp) / self.frequency());
             }
 
-                // the timer has always been enabled, but the cascade bit which was blocking the timer has been unset
-                if (new.enabled.read() and (self.cnt.cascade.read() and !new.cascade.read())) {
-                    // we want to reschedule the timer event, however we won't reload the counter.
-                    // the invariant here is that self._counter holds the already calculated paused value
+            // The counter is only reloaded on the rising edge of the enable bit
+            if (!self.cnt.enabled.read() and new.enabled.read()) self._counter = self._reload;
 
-                    self.rescheduleTimerExpire(0);
-                }
-            } else {
-                // the timer was previously disabeld
-
-                if (new.enabled.read()) {
-                    // timer should start counting (with a reloaded counter value)
-                    self._counter = self._reload;
-
-                    // if cascade happens to be set, the timer doesn't actually do anything though
-                    if (!new.cascade.read()) self.rescheduleTimerExpire(0);
-                }
-            }
+            // If Timer is enabled and we're not cascading, we need to schedule an overflow event
+            if (new.enabled.read() and !new.cascade.read()) self.rescheduleTimerExpire(0);
 
             self.cnt.raw = halfword;
         }
@@ -217,8 +202,7 @@ fn Timer(comptime id: u2) type {
             }
 
             // Reschedule Timer if we're not cascading
-            // TIM0 cascade value is N/A
-            if (id == 0 or !self.cnt.cascade.read()) {
+            if (!self.cnt.cascade.read()) {
                 self._counter = self._reload;
                 self.rescheduleTimerExpire(late);
             }

src/core/cpu.zig

@@ -7,7 +7,6 @@ const Scheduler = @import("scheduler.zig").Scheduler;
 const Logger = @import("../util.zig").Logger;
 
 const File = std.fs.File;
-const log = std.log.scoped(.Arm7Tdmi);
 
 // ARM Instructions
 pub const arm = struct {
@@ -235,6 +234,8 @@ pub const thumb = struct {
     }
 };
 
+const log = std.log.scoped(.Arm7Tdmi);
+
 pub const Arm7tdmi = struct {
     const Self = @This();
 
@@ -245,36 +246,34 @@ pub const Arm7tdmi = struct {
     cpsr: PSR,
     spsr: PSR,
 
-    bank: Bank,
+    /// Storage  for R8_fiq -> R12_fiq and their normal counterparts
+    /// e.g [r[0 + 8], fiq_r[0 + 8], r[1 + 8], fiq_r[1 + 8]...]
+    banked_fiq: [2 * 5]u32,
+
+    /// Storage for r13_<mode>, r14_<mode>
+    /// e.g. [r13, r14, r13_svc, r14_svc]
+    banked_r: [2 * 6]u32,
+
+    banked_spsr: [5]PSR,
 
     logger: ?Logger,
 
-    /// Bank of Registers from other CPU Modes
-    const Bank = struct {
-        /// Storage for r13_<mode>, r14_<mode>
-        /// e.g. [r13, r14, r13_svc, r14_svc]
-        r: [2 * 6]u32,
-
-        /// Storage  for R8_fiq -> R12_fiq and their normal counterparts
-        /// e.g [r[0 + 8], fiq_r[0 + 8], r[1 + 8], fiq_r[1 + 8]...]
-        fiq: [2 * 5]u32,
-
-        spsr: [5]PSR,
-
-        const Kind = enum(u1) {
-            R13 = 0,
-            R14,
-        };
-
-        pub fn create() Bank {
-            return .{
-                .r = [_]u32{0x00} ** 12,
-                .fiq = [_]u32{0x00} ** 10,
-                .spsr = [_]PSR{.{ .raw = 0x0000_0000 }} ** 5,
+    pub fn init(sched: *Scheduler, bus: *Bus, log_file: ?std.fs.File) Self {
+        return Self{
+            .r = [_]u32{0x00} ** 16,
+            .pipe = Pipeline.init(),
+            .sched = sched,
+            .bus = bus,
+            .cpsr = .{ .raw = 0x0000_001F },
+            .spsr = .{ .raw = 0x0000_0000 },
+            .banked_fiq = [_]u32{0x00} ** 10,
+            .banked_r = [_]u32{0x00} ** 12,
+            .banked_spsr = [_]PSR{.{ .raw = 0x0000_0000 }} ** 5,
+            .logger = if (log_file) |file| Logger.init(file) else null,
         };
     }
 
-        inline fn regIdx(mode: Mode, kind: Kind) usize {
+    inline fn bankedIdx(mode: Mode, kind: BankedKind) usize {
         const idx: usize = switch (mode) {
             .User, .System => 0,
             .Supervisor => 1,
@@ -287,7 +286,7 @@ pub const Arm7tdmi = struct {
         return (idx * 2) + if (kind == .R14) @as(usize, 1) else 0;
     }
 
-        inline fn spsrIdx(mode: Mode) usize {
+    inline fn bankedSpsrIndex(mode: Mode) usize {
         return switch (mode) {
             .Supervisor => 0,
             .Abort => 1,
@@ -298,23 +297,9 @@ pub const Arm7tdmi = struct {
         };
     }
 
-        inline fn fiqIdx(i: usize, mode: Mode) usize {
+    inline fn bankedFiqIdx(i: usize, mode: Mode) usize {
         return (i * 2) + if (mode == .Fiq) @as(usize, 1) else 0;
     }
-    };
-
-    pub fn init(sched: *Scheduler, bus: *Bus, log_file: ?std.fs.File) Self {
-        return Self{
-            .r = [_]u32{0x00} ** 16,
-            .pipe = Pipeline.init(),
-            .sched = sched,
-            .bus = bus,
-            .cpsr = .{ .raw = 0x0000_001F },
-            .spsr = .{ .raw = 0x0000_0000 },
-            .bank = Bank.create(),
-            .logger = if (log_file) |file| Logger.init(file) else null,
-        };
-    }
 
     pub inline fn hasSPSR(self: *const Self) bool {
         const mode = getModeChecked(self, self.cpsr.mode.read());
@@ -351,14 +336,14 @@ pub const Arm7tdmi = struct {
         switch (idx) {
             8...12 => {
                 if (current == .Fiq) {
-                    self.bank.fiq[Bank.fiqIdx(idx - 8, .User)] = value;
+                    self.banked_fiq[bankedFiqIdx(idx - 8, .User)] = value;
                 } else self.r[idx] = value;
             },
             13, 14 => switch (current) {
                 .User, .System => self.r[idx] = value,
                 else => {
-                    const kind = std.meta.intToEnum(Bank.Kind, idx - 13) catch unreachable;
-                    self.bank.r[Bank.regIdx(.User, kind)] = value;
+                    const kind = std.meta.intToEnum(BankedKind, idx - 13) catch unreachable;
+                    self.banked_r[bankedIdx(.User, kind)] = value;
                 },
             },
             else => self.r[idx] = value, // R0 -> R7  and R15
@@ -369,12 +354,12 @@ pub const Arm7tdmi = struct {
         const current = getModeChecked(self, self.cpsr.mode.read());
 
         return switch (idx) {
-            8...12 => if (current == .Fiq) self.bank.fiq[Bank.fiqIdx(idx - 8, .User)] else self.r[idx],
+            8...12 => if (current == .Fiq) self.banked_fiq[bankedFiqIdx(idx - 8, .User)] else self.r[idx],
             13, 14 => switch (current) {
                 .User, .System => self.r[idx],
                 else => blk: {
-                    const kind = std.meta.intToEnum(Bank.Kind, idx - 13) catch unreachable;
-                    break :blk self.bank.r[Bank.regIdx(.User, kind)];
+                    const kind = std.meta.intToEnum(BankedKind, idx - 13) catch unreachable;
+                    break :blk self.banked_r[bankedIdx(.User, kind)];
                 },
             },
             else => self.r[idx], // R0 -> R7  and R15
@@ -387,38 +372,38 @@ pub const Arm7tdmi = struct {
         // Bank R8 -> r12
         var i: usize = 0;
         while (i < 5) : (i += 1) {
-            self.bank.fiq[Bank.fiqIdx(i, now)] = self.r[8 + i];
+            self.banked_fiq[bankedFiqIdx(i, now)] = self.r[8 + i];
         }
 
         // Bank r13, r14, SPSR
         switch (now) {
             .User, .System => {
-                self.bank.r[Bank.regIdx(now, .R13)] = self.r[13];
-                self.bank.r[Bank.regIdx(now, .R14)] = self.r[14];
+                self.banked_r[bankedIdx(now, .R13)] = self.r[13];
+                self.banked_r[bankedIdx(now, .R14)] = self.r[14];
             },
             else => {
-                self.bank.r[Bank.regIdx(now, .R13)] = self.r[13];
-                self.bank.r[Bank.regIdx(now, .R14)] = self.r[14];
-                self.bank.spsr[Bank.spsrIdx(now)] = self.spsr;
+                self.banked_r[bankedIdx(now, .R13)] = self.r[13];
+                self.banked_r[bankedIdx(now, .R14)] = self.r[14];
+                self.banked_spsr[bankedSpsrIndex(now)] = self.spsr;
             },
         }
 
         // Grab R8 -> R12
         i = 0;
         while (i < 5) : (i += 1) {
-            self.r[8 + i] = self.bank.fiq[Bank.fiqIdx(i, next)];
+            self.r[8 + i] = self.banked_fiq[bankedFiqIdx(i, next)];
         }
 
         // Grab r13, r14, SPSR
         switch (next) {
             .User, .System => {
-                self.r[13] = self.bank.r[Bank.regIdx(next, .R13)];
-                self.r[14] = self.bank.r[Bank.regIdx(next, .R14)];
+                self.r[13] = self.banked_r[bankedIdx(next, .R13)];
+                self.r[14] = self.banked_r[bankedIdx(next, .R14)];
             },
             else => {
-                self.r[13] = self.bank.r[Bank.regIdx(next, .R13)];
-                self.r[14] = self.bank.r[Bank.regIdx(next, .R14)];
-                self.spsr = self.bank.spsr[Bank.spsrIdx(next)];
+                self.r[13] = self.banked_r[bankedIdx(next, .R13)];
+                self.r[14] = self.banked_r[bankedIdx(next, .R14)];
+                self.spsr = self.banked_spsr[bankedSpsrIndex(next)];
             },
         }
 
@@ -439,8 +424,8 @@ pub const Arm7tdmi = struct {
         self.r[13] = 0x0300_7F00;
         self.r[15] = 0x0800_0000;
 
-        self.bank.r[Bank.regIdx(.Irq, .R13)] = 0x0300_7FA0;
-        self.bank.r[Bank.regIdx(.Supervisor, .R13)] = 0x0300_7FE0;
+        self.banked_r[bankedIdx(.Irq, .R13)] = 0x0300_7FA0;
+        self.banked_r[bankedIdx(.Supervisor, .R13)] = 0x0300_7FE0;
 
         // self.cpsr.raw = 0x6000001F;
         self.cpsr.raw = 0x0000_001F;
@@ -530,10 +515,10 @@ pub const Arm7tdmi = struct {
             std.debug.print("R{}: 0x{X:0>8}\tR{}: 0x{X:0>8}\tR{}: 0x{X:0>8}\tR{}: 0x{X:0>8}\n", .{ i, self.r[i], i_1, self.r[i_1], i_2, self.r[i_2], i_3, self.r[i_3] });
         }
         std.debug.print("cpsr: 0x{X:0>8} ", .{self.cpsr.raw});
-        self.cpsr.toString();
+        prettyPrintPsr(&self.cpsr);
 
         std.debug.print("spsr: 0x{X:0>8} ", .{self.spsr.raw});
-        self.spsr.toString();
+        prettyPrintPsr(&self.spsr);
 
         std.debug.print("pipeline: {??X:0>8}\n", .{self.pipe.stage});
 
@@ -551,6 +536,76 @@ pub const Arm7tdmi = struct {
 
         std.debug.panic(format, args);
     }
+
+    fn prettyPrintPsr(psr: *const PSR) void {
+        std.debug.print("[", .{});
+
+        if (psr.n.read()) std.debug.print("N", .{}) else std.debug.print("-", .{});
+        if (psr.z.read()) std.debug.print("Z", .{}) else std.debug.print("-", .{});
+        if (psr.c.read()) std.debug.print("C", .{}) else std.debug.print("-", .{});
+        if (psr.v.read()) std.debug.print("V", .{}) else std.debug.print("-", .{});
+        if (psr.i.read()) std.debug.print("I", .{}) else std.debug.print("-", .{});
+        if (psr.f.read()) std.debug.print("F", .{}) else std.debug.print("-", .{});
+        if (psr.t.read()) std.debug.print("T", .{}) else std.debug.print("-", .{});
+        std.debug.print("|", .{});
+        if (getMode(psr.mode.read())) |mode| std.debug.print("{s}", .{modeString(mode)}) else std.debug.print("---", .{});
+
+        std.debug.print("]\n", .{});
+    }
+
+    fn modeString(mode: Mode) []const u8 {
+        return switch (mode) {
+            .User => "usr",
+            .Fiq => "fiq",
+            .Irq => "irq",
+            .Supervisor => "svc",
+            .Abort => "abt",
+            .Undefined => "und",
+            .System => "sys",
+        };
+    }
+
+    fn mgbaLog(self: *const Self, file: *const File, opcode: u32) !void {
+        const thumb_fmt = "{X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} cpsr: {X:0>8} | {X:0>4}:\n";
+        const arm_fmt = "{X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} {X:0>8} cpsr: {X:0>8} | {X:0>8}:\n";
+        var buf: [0x100]u8 = [_]u8{0x00} ** 0x100; // this is larger than it needs to be
+
+        const r0 = self.r[0];
+        const r1 = self.r[1];
+        const r2 = self.r[2];
+        const r3 = self.r[3];
+        const r4 = self.r[4];
+        const r5 = self.r[5];
+        const r6 = self.r[6];
+        const r7 = self.r[7];
+        const r8 = self.r[8];
+        const r9 = self.r[9];
+        const r10 = self.r[10];
+        const r11 = self.r[11];
+        const r12 = self.r[12];
+        const r13 = self.r[13];
+        const r14 = self.r[14];
+        const r15 = self.r[15] -| if (self.cpsr.t.read()) 2 else @as(u32, 4);
+
+        const c_psr = self.cpsr.raw;
+
+        var log_str: []u8 = undefined;
+        if (self.cpsr.t.read()) {
+            if (opcode >> 11 == 0x1E) {
+                // Instruction 1 of a BL Opcode, print in ARM mode
+                const other_half = self.bus.debugRead(u16, self.r[15] - 2);
+                const bl_opcode = @as(u32, opcode) << 16 | other_half;
+
+                log_str = try std.fmt.bufPrint(&buf, arm_fmt, .{ r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, c_psr, bl_opcode });
+            } else {
+                log_str = try std.fmt.bufPrint(&buf, thumb_fmt, .{ r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, c_psr, opcode });
+            }
+        } else {
+            log_str = try std.fmt.bufPrint(&buf, arm_fmt, .{ r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, c_psr, opcode });
+        }
+
+        _ = try file.writeAll(log_str);
+    }
 };
 
 const condition_lut = [_]u16{
@@ -629,22 +684,6 @@ pub const PSR = extern union {
     z: Bit(u32, 30),
     n: Bit(u32, 31),
     raw: u32,
-
-    fn toString(self: PSR) void {
-        std.debug.print("[", .{});
-
-        if (self.n.read()) std.debug.print("N", .{}) else std.debug.print("-", .{});
-        if (self.z.read()) std.debug.print("Z", .{}) else std.debug.print("-", .{});
-        if (self.c.read()) std.debug.print("C", .{}) else std.debug.print("-", .{});
-        if (self.v.read()) std.debug.print("V", .{}) else std.debug.print("-", .{});
-        if (self.i.read()) std.debug.print("I", .{}) else std.debug.print("-", .{});
-        if (self.f.read()) std.debug.print("F", .{}) else std.debug.print("-", .{});
-        if (self.t.read()) std.debug.print("T", .{}) else std.debug.print("-", .{});
-        std.debug.print("|", .{});
-        if (getMode(self.mode.read())) |m| std.debug.print("{s}", .{m.toString()}) else std.debug.print("---", .{});
-
-        std.debug.print("]\n", .{});
-    }
 };
 
 const Mode = enum(u5) {
@@ -655,18 +694,11 @@ const Mode = enum(u5) {
     Abort = 0b10111,
     Undefined = 0b11011,
     System = 0b11111,
+};
 
-    fn toString(self: Mode) []const u8 {
-        return switch (self) {
-            .User => "usr",
-            .Fiq => "fiq",
-            .Irq => "irq",
-            .Supervisor => "svc",
-            .Abort => "abt",
-            .Undefined => "und",
-            .System => "sys",
-        };
-    }
+const BankedKind = enum(u1) {
+    R13 = 0,
+    R14,
 };
 
 fn getMode(bits: u5) ?Mode {

src/core/emu.zig

@@ -56,7 +56,7 @@ fn inner(comptime kind: RunKind, audio_sync: bool, quit: *Atomic(bool), schedule
         .Unlimited, .UnlimitedFPS => {
             log.info("Emulation w/out video sync", .{});
 
-            while (!quit.load(.Monotonic)) {
+            while (!quit.load(.SeqCst)) {
                 runFrame(scheduler, cpu);
                 audioSync(audio_sync, cpu.bus.apu.stream, &cpu.bus.apu.is_buffer_full);
 
@@ -68,7 +68,7 @@ fn inner(comptime kind: RunKind, audio_sync: bool, quit: *Atomic(bool), schedule
             var timer = Timer.start() catch @panic("failed to initalize std.timer.Timer");
             var wake_time: u64 = frame_period;
 
-            while (!quit.load(.Monotonic)) {
+            while (!quit.load(.SeqCst)) {
                 runFrame(scheduler, cpu);
                 const new_wake_time = videoSync(&timer, wake_time);
 

src/main.zig

@@ -87,7 +87,7 @@ pub fn main() void {
         cpu.fastBoot();
     }
 
-    var gui = Gui.init(&bus.pak.title, &bus.apu, width, height) catch |e| exitln("failed to init gui: {}", .{e});
+    var gui = Gui.init(&bus.pak.title, &bus.apu, width, height);
     defer gui.deinit();
 
     gui.run(&cpu, &scheduler) catch |e| exitln("failed to run gui thread: {}", .{e});

src/platform.zig

@@ -15,7 +15,7 @@ const gba_height = @import("core/ppu.zig").height;
 pub const sample_rate = 1 << 15;
 pub const sample_format = SDL.AUDIO_U16;
 
-const default_title = "ZBA";
+const default_title: []const u8 = "ZBA";
 
 pub const Gui = struct {
     const Self = @This();
@@ -44,7 +44,7 @@ pub const Gui = struct {
 
     program_id: gl.GLuint,
 
-    pub fn init(title: *const [12]u8, apu: *Apu, width: i32, height: i32) !Self {
+    pub fn init(title: *const [12]u8, apu: *Apu, width: i32, height: i32) Self {
         if (SDL.SDL_Init(SDL.SDL_INIT_VIDEO | SDL.SDL_INIT_EVENTS | SDL.SDL_INIT_AUDIO) < 0) panic();
         if (SDL.SDL_GL_SetAttribute(SDL.SDL_GL_CONTEXT_PROFILE_MASK, SDL.SDL_GL_CONTEXT_PROFILE_CORE) < 0) panic();
         if (SDL.SDL_GL_SetAttribute(SDL.SDL_GL_CONTEXT_MAJOR_VERSION, 3) < 0) panic();
@@ -53,7 +53,7 @@ pub const Gui = struct {
         const win_scale = @intCast(c_int, config.config().host.win_scale);
 
         const window = SDL.SDL_CreateWindow(
-            default_title,
+            default_title.ptr,
             SDL.SDL_WINDOWPOS_CENTERED,
             SDL.SDL_WINDOWPOS_CENTERED,
             @as(c_int, width * win_scale),
@@ -64,10 +64,10 @@ pub const Gui = struct {
         const ctx = SDL.SDL_GL_CreateContext(window) orelse panic();
         if (SDL.SDL_GL_MakeCurrent(window, ctx) < 0) panic();
 
-        try gl.load(ctx, Self.glGetProcAddress);
+        gl.load(ctx, Self.glGetProcAddress) catch @panic("gl.load failed");
         if (SDL.SDL_GL_SetSwapInterval(@boolToInt(config.config().host.vsync)) < 0) panic();
 
-        const program_id = try compileShaders();
+        const program_id = compileShaders();
 
         return Self{
             .window = window,
@@ -78,7 +78,7 @@ pub const Gui = struct {
         };
     }
 
-    fn compileShaders() !gl.GLuint {
+    fn compileShaders() gl.GLuint {
         // TODO: Panic on Shader Compiler Failure + Error Message
         const vert_shader = @embedFile("shader/pixelbuf.vert");
         const frag_shader = @embedFile("shader/pixelbuf.frag");
@@ -89,16 +89,12 @@ pub const Gui = struct {
         gl.shaderSource(vs, 1, &[_][*c]const u8{vert_shader}, 0);
         gl.compileShader(vs);
 
-        if (!shader.didCompile(vs)) return error.VertexCompileError;
-
         const fs = gl.createShader(gl.FRAGMENT_SHADER);
         defer gl.deleteShader(fs);
 
         gl.shaderSource(fs, 1, &[_][*c]const u8{frag_shader}, 0);
         gl.compileShader(fs);
 
-        if (!shader.didCompile(fs)) return error.FragmentCompileError;
-
         const program = gl.createProgram();
         gl.attachShader(program, vs);
         gl.attachShader(program, fs);
@@ -108,7 +104,7 @@ pub const Gui = struct {
     }
 
     // Returns the VAO ID since it's used in run()
-    fn generateBuffers() struct { c_uint, c_uint, c_uint } {
+    fn generateBuffers() [3]c_uint {
         var vao_id: c_uint = undefined;
         var vbo_id: c_uint = undefined;
         var ebo_id: c_uint = undefined;
@@ -158,21 +154,13 @@ pub const Gui = struct {
         var quit = std.atomic.Atomic(bool).init(false);
         var tracker = FpsTracker.init();
 
-        var buffer_ids = Self.generateBuffers();
-        defer {
-            gl.deleteBuffers(1, &buffer_ids[2]); // EBO
-            gl.deleteBuffers(1, &buffer_ids[1]); // VBO
-            gl.deleteVertexArrays(1, &buffer_ids[0]); // VAO
-        }
-        const vao_id = buffer_ids[0];
-
-        const tex_id = Self.generateTexture(cpu.bus.ppu.framebuf.get(.Renderer));
-        defer gl.deleteTextures(1, &tex_id);
-
         const thread = try std.Thread.spawn(.{}, emu.run, .{ &quit, scheduler, cpu, &tracker });
         defer thread.join();
 
-        var title_buf: [0x100]u8 = undefined;
+        var title_buf: [0x100]u8 = [_]u8{0} ** 0x100;
+
+        const vao_id = Self.generateBuffers()[0];
+        _ = Self.generateTexture(cpu.bus.ppu.framebuf.get(.Renderer));
 
         emu_loop: while (true) {
             var event: SDL.SDL_Event = undefined;
@@ -180,50 +168,54 @@ pub const Gui = struct {
                 switch (event.type) {
                     SDL.SDL_QUIT => break :emu_loop,
                     SDL.SDL_KEYDOWN => {
+                        const io = &cpu.bus.io;
                         const key_code = event.key.keysym.sym;
-                        var keyinput = cpu.bus.io.keyinput.load(.Monotonic);
 
                         switch (key_code) {
-                            SDL.SDLK_UP => keyinput.up.unset(),
-                            SDL.SDLK_DOWN => keyinput.down.unset(),
-                            SDL.SDLK_LEFT => keyinput.left.unset(),
-                            SDL.SDLK_RIGHT => keyinput.right.unset(),
-                            SDL.SDLK_x => keyinput.a.unset(),
-                            SDL.SDLK_z => keyinput.b.unset(),
-                            SDL.SDLK_a => keyinput.shoulder_l.unset(),
-                            SDL.SDLK_s => keyinput.shoulder_r.unset(),
-                            SDL.SDLK_RETURN => keyinput.start.unset(),
-                            SDL.SDLK_RSHIFT => keyinput.select.unset(),
+                            SDL.SDLK_UP => io.keyinput.up.unset(),
+                            SDL.SDLK_DOWN => io.keyinput.down.unset(),
+                            SDL.SDLK_LEFT => io.keyinput.left.unset(),
+                            SDL.SDLK_RIGHT => io.keyinput.right.unset(),
+                            SDL.SDLK_x => io.keyinput.a.unset(),
+                            SDL.SDLK_z => io.keyinput.b.unset(),
+                            SDL.SDLK_a => io.keyinput.shoulder_l.unset(),
+                            SDL.SDLK_s => io.keyinput.shoulder_r.unset(),
+                            SDL.SDLK_RETURN => io.keyinput.start.unset(),
+                            SDL.SDLK_RSHIFT => io.keyinput.select.unset(),
                             else => {},
                         }
-
-                        cpu.bus.io.keyinput.store(keyinput.raw, .Monotonic);
                     },
                     SDL.SDL_KEYUP => {
+                        const io = &cpu.bus.io;
                         const key_code = event.key.keysym.sym;
-                        var keyinput = cpu.bus.io.keyinput.load(.Monotonic);
 
                         switch (key_code) {
-                            SDL.SDLK_UP => keyinput.up.set(),
-                            SDL.SDLK_DOWN => keyinput.down.set(),
-                            SDL.SDLK_LEFT => keyinput.left.set(),
-                            SDL.SDLK_RIGHT => keyinput.right.set(),
-                            SDL.SDLK_x => keyinput.a.set(),
-                            SDL.SDLK_z => keyinput.b.set(),
-                            SDL.SDLK_a => keyinput.shoulder_l.set(),
-                            SDL.SDLK_s => keyinput.shoulder_r.set(),
-                            SDL.SDLK_RETURN => keyinput.start.set(),
-                            SDL.SDLK_RSHIFT => keyinput.select.set(),
+                            SDL.SDLK_UP => io.keyinput.up.set(),
+                            SDL.SDLK_DOWN => io.keyinput.down.set(),
+                            SDL.SDLK_LEFT => io.keyinput.left.set(),
+                            SDL.SDLK_RIGHT => io.keyinput.right.set(),
+                            SDL.SDLK_x => io.keyinput.a.set(),
+                            SDL.SDLK_z => io.keyinput.b.set(),
+                            SDL.SDLK_a => io.keyinput.shoulder_l.set(),
+                            SDL.SDLK_s => io.keyinput.shoulder_r.set(),
+                            SDL.SDLK_RETURN => io.keyinput.start.set(),
+                            SDL.SDLK_RSHIFT => io.keyinput.select.set(),
                             SDL.SDLK_i => {
                                 comptime std.debug.assert(sample_format == SDL.AUDIO_U16);
                                 log.err("Sample Count: {}", .{@intCast(u32, SDL.SDL_AudioStreamAvailable(cpu.bus.apu.stream)) / (2 * @sizeOf(u16))});
                             },
-                            // SDL.SDLK_j => log.err("Scheduler Capacity: {} | Scheduler Event Count: {}", .{ scheduler.queue.capacity(), scheduler.queue.count() }),
-                            SDL.SDLK_k => {},
+                            SDL.SDLK_j => log.err("Scheduler Capacity: {} | Scheduler Event Count: {}", .{ scheduler.queue.capacity(), scheduler.queue.count() }),
+                            SDL.SDLK_k => {
+                                // Dump IWRAM to file
+                                log.info("PC: 0x{X:0>8}", .{cpu.r[15]});
+                                log.info("LR: 0x{X:0>8}", .{cpu.r[14]});
+                                // const iwram_file = try std.fs.cwd().createFile("iwram.bin", .{});
+                                // defer iwram_file.close();
+
+                                // try iwram_file.writeAll(cpu.bus.iwram.buf);
+                            },
                             else => {},
                         }
-
-                        cpu.bus.io.keyinput.store(keyinput.raw, .Monotonic);
                     },
                     else => {},
                 }
@@ -238,15 +230,16 @@ pub const Gui = struct {
             gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_INT, null);
             SDL.SDL_GL_SwapWindow(self.window);
 
-            const dyn_title = std.fmt.bufPrintZ(&title_buf, "ZBA | {s} [Emu: {}fps] ", .{ self.title, tracker.value() }) catch unreachable;
+            const dyn_title = std.fmt.bufPrint(&title_buf, "ZBA | {s} [Emu: {}fps] ", .{ self.title, tracker.value() }) catch unreachable;
             SDL.SDL_SetWindowTitle(self.window, dyn_title.ptr);
         }
 
-        quit.store(true, .Monotonic); // Terminate Emulator Thread
+        quit.store(true, .SeqCst); // Terminate Emulator Thread
     }
 
     pub fn deinit(self: *Self) void {
         self.audio.deinit();
+        // TODO: Buffer deletions
         gl.deleteProgram(self.program_id);
         SDL.SDL_GL_DeleteContext(self.ctx);
         SDL.SDL_DestroyWindow(self.window);
@@ -303,28 +296,6 @@ const Audio = struct {
     }
 };
 
-const shader = struct {
-    const Kind = enum { vertex, fragment };
-    const log = std.log.scoped(.Shader);
-
-    fn didCompile(id: gl.GLuint) bool {
-        var success: gl.GLint = undefined;
-        gl.getShaderiv(id, gl.COMPILE_STATUS, &success);
-
-        if (success == 0) err(id);
-
-        return success == 1;
-    }
-
-    fn err(id: gl.GLuint) void {
-        const buf_len = 512;
-        var error_msg: [buf_len]u8 = undefined;
-
-        gl.getShaderInfoLog(id, buf_len, 0, &error_msg);
-        log.err("{s}", .{std.mem.sliceTo(&error_msg, 0)});
-    }
-};
-
 fn panic() noreturn {
     const str = @as(?[*:0]const u8, SDL.SDL_GetError()) orelse "unknown error";
     @panic(std.mem.sliceTo(str, 0));

src/util.zig

@@ -49,7 +49,7 @@ pub const FpsTracker = struct {
 
     pub fn value(self: *Self) u32 {
         if (self.timer.read() >= std.time.ns_per_s) {
-            self.fps = self.count.swap(0, .Monotonic);
+            self.fps = self.count.swap(0, .SeqCst);
             self.timer.reset();
         }
 
@@ -148,7 +148,7 @@ pub const Logger = struct {
         if (cpu.cpsr.t.read()) {
             if (opcode >> 11 == 0x1E) {
                 // Instruction 1 of a BL Opcode, print in ARM mode
-                const low = cpu.bus.dbgRead(u16, cpu.r[15] - 2);
+                const low = cpu.bus.dbgRead(u16, cpu.r[15]);
                 const bl_opcode = @as(u32, opcode) << 16 | low;
 
                 self.print(arm_fmt, Self.fmtArgs(cpu, bl_opcode)) catch @panic("failed to write to log file");